digiplexer fmx410 user manuel - radikal elektronik · 2008. 6. 23. · the operational blocks of...

Audemat-Aztec SA – Audemat-Aztec INC WEB: www.audemat-aztec.com - e-mail: [email protected]

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DIGIPLEXER FMX410

USER MANUEL

Issue : 08/07

Language : English

AUDEMAT-AZTEC ® and Navigator ® are registered trademarks of AUDEMAT-AZTEC Company.


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SUMMARY

BEFORE STARTING...................................................................................................................................... 5

INTRODUCTION............................................................................................................................................ 6 WHY "DIGIPLEXER" ? .................................................................................................................................. 6 YOU HAVE JUST ACQUIRED AN FMX410 OR FMX440 DIGIPLEXER ........................................................... 6 FMX410 DIGIPLEXER GENERAL SPECIFICATIONS........................................................................................... 10

PHYSICAL COMPONENTS AND INTERFACES .................................................................................... 13 THE DIGIPLEXER CASE ................................................................................................................................... 13 REAR PANEL................................................................................................................................................... 13 FRONT PANEL ................................................................................................................................................. 16 INTERNAL COMPOSITION OF THE DIGIPLEXER................................................................................................. 17 FMX410 PCB : JUMPERS, POINTS OF ADJUSTMENT........................................................................................ 18 SCHEMATIC .................................................................................................................................................... 19

ABOUT THE COMPOSITE MULTIPLEX SIGNAL................................................................................ 19

ABOUT THE COMPOSITE MULTIPLEX SIGNAL................................................................................ 20 MULTIPLEX SIGNAL COMPOSITION ................................................................................................................. 20 LEVELS AND UNITS USED TO DESCRIBE THE MULTIPLEX SIGNAL .................................................................... 21 PRINCIPLES OF DIGITAL SYNTHESIS OF THE MULTIPLEX COMPOSITE SIGNAL .................................................. 23 ADVANTAGES OF GLOBAL DIGITAL SYNTHESIS OF THE MULTIPLEX SIGNAL ................................................... 24 INSTANTANEOUS DEVIATION AND POWER RELATED TO MODULATION ............................................................ 25 THE "MULTIPLEX LIMITER " OR " MULTIPLEX CLIPPER " FUNCTION .............................................................. 25 AGC FUNCTION.............................................................................................................................................. 26 "ADDPWR" FUNCTION.................................................................................................................................. 26 THE MPX LIMITER POWER FUNCTION ................................................................................................. 27

Description of the new commands................................................................................................... 27 Activation of the MPX Power Limiter ............................................................................................... 27 Example of procedure for using the FMX410 limiter ..................................................................... 28

SUB-CARRIER DEVIATION ............................................................................................................................... 28 EFFECT OF THE SUB-CARRIER DEVIATION ON THE GLOBAL DEVIATION........................................................... 29 THE IMPORTANCE OF SUB-CARRIER SYNCHRONISATION ................................................................................. 30

DIGIPLEXER INSTALLATION AND USER’S GUIDE .......................................................................... 31 POWER SUPPLY............................................................................................................................................... 31 GENERAL INSTALLATION LAYOUT OF THE EQUIPMENT ................................................................................... 31 WHERE TO CONNECT THE INCOMING AUDIO SIGNAL, LEFT, RIGHT ? .............................................................. 32 WHERE TO CONNECT THE MPX OUTPUT OF THE DIGIPLEXER......................................................................... 33 UNDERSTANDING AND CHOOSING THE « BYPASS » FUNCTION ....................................................................... 33 INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL RDS ENCODER........................................................ 34 INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL STEREOPHONIC ENCODER ....................................... 35 INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL COMPOSITE LIMITER................................................ 36 INSTALLATION OF THE DIGIPLEXER AS AN EMERGENCY BACKUP TO EXISTING EQUIPMENT ............................ 36 TO CONNECT EMERGENCY BACKUP EQUIPMENT TO THE DIGIPLEXER ............................................................. 37 TO USE THE MPX INPUT FOR THE INSERTION OF AN SCA OR ADDITIONAL SIGNAL......................................... 37 TO SYNCHRONISE THE DIGIPLEXER BY AN EXTERNAL CLOCK (19 KHZ) ......................................................... 37 TO RECOVER THE DIGIPLEXER CLOCK REFERENCE (19KHZ)........................................................................... 38


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TO ADJUST THE NOMINAL SENSITIVITY OF THE DIGIPLEXER AUDIO INPUTS .................................................... 39 TO ADJUST THE NOMINAL OUTPUT LEVEL (LVLO) OF THE DIGIPLEXER ......................................................... 40 REMINDERS ON THE PRE-EMPHASIS FUNCTION ............................................................................................... 41 MONOPHONIC TRANSMISSION ........................................................................................................................ 41 STEREOPHONIC TRANSMISSION ...................................................................................................................... 42 TO TRANSMIT THE TEST SIGNALS.................................................................................................................... 42 MULTIPLEX PROCESSOR OPERATION (AGC, CLIP, ADDPWR, SEFFECT)................................................... 44 TO MODIFY THE CUT OFF FREQUENCIES ON THE AUDIO TRACKS (L+R) ET (L-R) ............................................ 45 TO SAVE THE CURRENT CONFIGURATION IN USER MEMORY............................................................................ 45 TO USE THE CONFIGURATION IN USER MEMORY FOR TRANSMISSION .............................................................. 45 TO RESTRICT ACCESS TO THE DIGIPLEXER PARAMETERS ................................................................................ 46 TO PERSONALISE THE WELCOME MESSAGE OF THE DIGIPLEXER (FRONT PANEL) ............................................ 46 TO USE THE DIGIPLEXER WITH A MODEM....................................................................................................... 46 TO DISPLAY THE COMPOSITE MULTIPLEX OUTPUT LEVEL................................................................................ 47 TO DISPLAY THE PREDICTED DEVIATION (MULTIPLEX SIGNAL) ON PC ........................................................... 48 TO DISPLAY THE PREDICTED POWER (MULTIPLEX SIGNAL) ON PC.................................................................. 49 TO DISPLAY THE ACTION OF THE AGC FUNCTION........................................................................................... 49 AUTOMATICAL PROCEDURE FOR THE ANALOGUE INPUTS CALIBRATION ......................................................... 50

TO USE THE FRONT PANEL..................................................................................................................... 51 TO USE THE DISPLAY AND THE "SEL" AND "OK" BUTTONS............................................................................ 51 WELCOME MESSAGES ON THE FRONT PANEL.................................................................................................. 52 TO DISPLAY THE PARAMETERS ON FRONT PANEL ........................................................................................... 52 MENUS ALLOWING THE MODIFICATION OF THE PARAMETERS......................................................................... 52 MENUS ALLOWING THE MODIFICATION OF THE PARAMETERS......................................................................... 53

MENU ALLOWING THE ADJUSTMENT OF THE PROCESS...................................................................... 53 MENU ALLOWING THE ADJUSTMENT OF THE PROCESS................................................................................. 54 MENUS ALLOWING THE EXECUTION OF ACTIONS ............................................................................................ 54

TO USE THE DIGIPLEXER VIA THE ASCII PROTOCOL AND COM0............................................ 55 TO CONNECT A PC TO THE COM0 PORT ......................................................................................................... 55 CHOOSING A "TERMINAL" APPLICATION AND PRINCIPLES OF THE ASCII DIALOGUE....................................... 55 THE ASCII INSTRUCTION SET RELATIVE TO THE HARDWARE CONFIGURATION OF THE FMX410 DIGIPLEXER 58

TO USE THE DIGIPLEXER WITH THE PC SOFTWARE SUPPLIED ............................................... 63 TO USE THE « DIGIPLEX » SOFTWARE TO CONFIGURE THE DIGIPLEXER HARDWARE.................................... 64 DIGIPLEX SOFTWARE : GENERAL SET UP SCREEN (F2)................................................................................ 64 DIGIPLEX SOFTWARE : GENERAL SET UP SCREEN (F2)................................................................................ 65 PARAMETER CONFIGURATION SCREEN RELATED TO THE SIGNALS USED OR GENERATED BY THE DIGIPLEXER

(F3) ................................................................................................................................................................... 65 PARAMETER CONFIGURATION SCREEN RELATED TO THE SIGNALS USED OR GENERATED BY THE DIGIPLEXER

(F3) ................................................................................................................................................................... 66 LOGICIEL DIGIPLEX : GENERATING SIGNAL TEST......................................................................................... 66 LOGICIEL DIGIPLEX : GENERATING SIGNAL TEST......................................................................................... 67 DIGIPLEX SOFTWARE : DIGITAL MULTIPLEX SIGNAL DISPLAY..................................................................... 67 TO CONFIGURE THE RDS PARAMETERS WITH THE "FMB10CFG" SOFTWARE (WINDOWS©).......................... 67 TO CONFIGURE THE RDS PARAMETERS WITH THE "FMB10CFG" SOFTWARE (WINDOWS©).......................... 68

TO USE RDS WITH THE FMX410 DIGIPLEXER .................................................................................. 69 A FEW WORDS ABOUT RDS ............................................................................................................................ 69 ASCII INSTRUCTION SET FOR THE CONFIGURATION OF RDS DATA : FMX410 ............................................... 70 TO SET UP THE LIST OF AUTOMATIC FREQUENCIES TO BE TRANSMITTED........................................................ 77 TO SET UP THE PI AND PS CODES FOR THE FMX410 DIGIPLEXER .................................................................. 77


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TO CREATE A PS KNOWN AS "REVOLVING" OR "SCROLLING" (FMX410)....................................................... 78 TO SET UP THE DI, PTY, MS CODES OF THE FMX410 DIGIPLEXER................................................................ 78 TO SET UP THE TP CODE (FMX410) ............................................................................................................... 78 WHAT IS THE TA CODE USED FOR, HOW DOES IT WORK ? SWITCHING THE TA. (FMX410) ........................... 79 RADIO TEXT TRANSMISSION........................................................................................................................... 79 TO BROADCAST DYNAMIC DATA..................................................................................................................... 80 TO USE THE AUDEMAT-AZTEC "RDS-MCS" SOFTWARE TO ADDRESS THE RDS SECTION........................ 80 ASCII AND UECP (UER-SPB490) PROTOCOLS ............................................................................................ 82 THE SWITCHING OF THE UECP (UER-SPB490) PROTOCOL............................................................................ 82 LAYER 2 COMMUNICATION PROTOCOL AND TIMINGS REQUIREMENTS ............................................................ 83 RDS CONTROL DIFFERENCES BETWEEN THE FMX410 DIGIPLEXER AND THE FMB10 ENCODER ................... 84

EXTENDED RDS : THE FMX440 DIGIPLEXER.................................................................................... 85

FREQUENTLY ASKED QUESTIONS (FAQ) ........................................................................................... 86 WHAT IS THE RELATIONSHIP BETWEEN THE ACTUAL RDS LEVEL AND THAT DEFINED IN THE UECP (UER-

SPB490) PROTOCOL ? ........................................................................................................................................ 86 WHAT IS THE RELATIONSHIP BETWEEN THE ACTUAL RDS PHASE AND THAT DEFINED IN THE UECP (UER-

SPB490) PROTOCOL .......................................................................................................................................... 86 WHY DOESN’T THE LVLO LEVEL REACT ON THE BAR GRAPH DISPLAY ?........................................................ 86 DOES THE DIGIPLEXER ALLOW DC COMPONENTS TO PASS ? .......................................................................... 87 THE FIRST CHARACTER OF THE DISPLAYED PS FLUCTUATES ON CERTAIN CAR RADIO RECEIVERS .................. 87


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Before starting...

☞ Have you read this manual?

If the response to this question is NO, AUDEMAT-AZTEC invites you to spend a little time to

read it. In addition to the information on the FMX410 Digiplexer product, you will find precious

information concerning the principles of frequency modulation (FM) and of the RDS system in

radiobroadcasting.

We wish you good reading. If you have any comments concerning this documentation, please contact the AUDEMAT-AZTEC product manager.


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Introduction

Why "DIGIPLEXER" ? ...

Since 1990, AUDEMAT-AZTEC have worked in the RDS field. In doing so, we have been

closely interested in the composite multiplexed signal which carries not only the RDS, but also

the sound of the Radio Station that you are preparing to "DIGIPLEX ".

Of course, from the beginning we have thought of proposing a Stereophonic encoder

combined with an RDS encoder. This would have been simple, if we had, without technical

innovation, integrated an analogue synthesis or "falsely digital" stereophonic encoder into our

RDS encoder.

Such a combination would have married 2 technologies and 2 performance levels without any

relation. That’s why AUDEMAT-AZTEC decided to create a new concept in FM : That is to

synthesise globally and digitally the Multiplex signal : "Digiplex ", as in Digi(tal)-(Multi)plex.

You have just acquired an FMX410 or FMX440 DIGIPLEXER ...

These products contain high technology developments incorporating the most sophisticated

signal processing techniques.

In practice, these are DSP (Digital Signal Processor) which by software, assure all the

synthesis functions of the different composite multiplexed signal components delivered by the

Digiplexer.

Owing to it’s technological progress in RDS (Radio Data System), AUDEMAT-AZTEC SA has

invested technologically in the stereophonic encoding and multiplex processing (clipping,

power enhancement, AGC of the FMX410 Digiplexer.

The FMX410 Digiplexer ensures RDS and RBDS functions (For USA).


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DIGIPLEXER : 10 key points...

① Price reduction of the functions due to their integration in a single unit.

② Reduction in space taken in central control rooms and transmission sites

③ Flexibility of AUDIO, STEREO, RDS parameters and multiplex processing

④ Simplicity and repeatability of the digital configuration

⑤ Elimination of drift owing to a DSP based digital architecture

⑥ Extremely simple to operate owing to it’s PC configuration software

⑦ A digital multiplex limiter which processes the multiplex signal at it’s source

⑧ A product designed to accept the DDJ and NHK systems

⑨ A system and sampling frequency of adjoining signals of 500 kHz

⑩ The complete remote control of parameters, via modem


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The block diagram above shows in a synthetic manner the operational blocks of the FMX410 Digiplexer.

The Technology in the Digiplexer... ① Digital audio input (AES/EBU S-PDIF)

② Number of DSPs : 5, DSP operating frequency = approximately 60 MHz

③ Sampling frequency > 400 kHz

④ Variable Gain Bypass function

⑤ Multiplex calculations and encoding performed in 24 bit, Fech > 400 kHz

⑥ Digital adjustment of the analogue input level on a large dynamic range

⑦ Direct expression of the Multiplex signal level in kHz.

⑧ Optional digital output of the Multiplex signal (requires 3 additional connectors)

⑨ A complete synchronisation unit for synchronous FM applications

Digital RDS encoder

Digital Stereo

Encoder

Digital Summation

Σ

Digital Multiplex Limiter

Audio Interface

AES/EBU Analogue or Digital

RS232/RS422 interface RDS data ASCII or

EBU-SPB490 Protocol

RDS data

Audio (L, R)

Composite Multiplex Digital or Analogue

S T U D I O

F M

P I L O T

DIGIPLEXER BLOCK DIAGRAM

System sampling frequency Fech>400kHz. SYNCHRO


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In the majority of cases, the Digiplexer ("Digital-Multiplex") replaces several pieces of

equipment installed on the transmission site and/or in the studio. You probably find yourself

partially or completely in the set up shown below (left), which describes in a general and

schematic manner your actual transmission chain, and that which it will become, once the

Digiplexer is installed:

Stereo Encoder

Multiplex Limiter (Clipper+Optimiser)

AES-EBU digital/ analogue converter D

A DIGIPLEXER FMX410

Digital or analogue audio signal coming from the studio by line,

satellite or beam. Before the AZTEC Digiplexer

After the AZTEC Digiplexer

Pilot transmitter 87,6 - 107,9 MHz 10 to 50 Watts

Power amplifier 100W to 10kW

A composite multiplexed signal is applied to the transmitter pilot. Frequency band 0 to 100 kHz

Transmission antenna

Audio (BF) Left, Right

RDS Encoder


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FMX410 Digiplexer general specifications

Audio inputs outputs: Digital audio input : XLR connector, galvanic insulation, symmetrical format. Auto-adaptation to the AES/EBU data formats applied. Compatible with the digital audio formats : AES/EBU, IEC958, S/PDIF, EIAJ CP-340 Adjustable level from 0dBfs to -10dBfs Emergency back-up : In case of synchronisation failure on the digital audio frames, automatic switching and capturing of sound signal on the analogue audio input. Analogue audio input : 1 connector XLR per channel Symmetrical format Impedance : 600 ohms (easily changed) Adjustable nominal level : -18dBu to +18dbu. Nominal reserve : 6dB Multiplex input : BNC, asymmetrical format. Adjustable nominal level : -18dBu to +18dBu. « Bypass and adder » function : configurable retransmission gain : -60dB to +20dB. Extraction of a 19000 Hz pilot signal contained in the MPX signal applied for the phasing of the Digiplexer clock. Digital Multiplex Output (option) : Sampling : Fech>400kHz, 16 bit serial bus CLK, SYNC and DATA compatible DSP. Applications: driving of DDS transmitters (Direct Digital synthesisers). Driving of Digital beams. Analogue multiplex output : BNC, Asymmetrical format. Nominal adjustable level : -18 dBu to +18 dBu. Recommended load impedance : 600 ohms. Nominal deviation : 75 kHz Maximum deviation : 150 kHz

Stereophonic encoding : Harmonic distortion : < 0.03% (1kHz) Separation : Better than 60 dB : (1kHz sinusoidal) 38kHz suppression : Better than 70 dB. Audio pass band : Configurable by the DIGIPLEX.EXE software (delivered with the Digiplexer) between 20 Hz and 18500 Hz. Low pass filter for each audio channel : Better than -86 dB attenuation at 16.7kHz, configured to 15kHz for a low pass filter (parameter configured at the delivery) Linear phase. High pass filter for each audio channel : Configurable from 0 to 15kHz with the DIGIPLEX set up software. Pass band ripple : Less than 0.1 dB Pilot frequency deviation : Adjustable in kHz, in steps of 0.1kHz (via front panel, RS232 or DIGIPLEX set up software) Driver frequency stability : 0.5Hz 0°C to 50°C Test signals : Predefined : 593.75Hz, 1187.5Hz, 14843Hz sinusoidal. Channel combinations : Left only, Right only, Left = Right, Left = -(Right).


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RDS encoding: Out of band rejection : Conforms to the standard CENELEC EN50067 (Less than -96dB, CENELEC specified conditions). 57kHz suppression : better than 70dB Deviation : adjustable in kHz (unit of deviation), steps of 0.1kHz RDS application examples on FMX410 : PS, PI, AF, RADIO TEXT, dGPS, PTYN, FBT, RBDS. Compatibility with the FMB10 RDS encoder. Free format groups. Options : Upgrading the FMX410 into a FMX440 : RDS40 extension board : refer to the technical manual RDS40 (ref : RDS1930.DOC) Multiplex signal processing : Clipper : predicting Algorithm ( AUDEMAT-AZTEC property). Possibility to activate or desactivate from the front panel AGC : dynamic control of the analogue audio input with adjustment of ATTACK and DECAY time and GATE threshold Power enhancement : adjustable from 0 to 5 dB (1dB step). Action on L-R : increasing or decreasing of the stereo effect Communication port(s): FMX410 : COM0 on front panel RS232 (1200 to 9600 bits/s). Protocols : ASCII. Configurable Modem initialisation sequence. UECP protocol (UER-SPB490) accepted for RDS and manufacturer commands.

Parametric display: Display : High luminosity LED alphanumeric display. Shows the digital values of the parameters related to stereophonic encoding, at input, intermediate and measured output levels. Bar-graph display of actual deviation 11 green LEDS, 1 yellow LED, 3 red LEDS, zoom mode, peak value of actual deviation. Configuration: ➫ Via COM0 (RS232): ASCII commands with a user friendly protocol can be used with a « terminal » type application. ➫ Via the « DIGIPLEX.EXE » PC software : Configuration software delivered with the product for Windows© which permits the Stereo Encoding sections, limiter, and RDS data to be set up. The DIGIPLEX software integrates remote control via a Modem. ➫ Via the front panel : 2 buttons and an led alphanumeric display enable the configuration of the physical parameters of the Digiplexer. Saving the configurations : 2 memories containing the user defined parameters. 1 « factory configured » memory may be recalled for a rapid set up change. Saving of the configurations on diskette or hard disk via the DIGIPLEX.EXE set up program.


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Monitoring: Display : peak digital value, 0.1kHz resolution. Bar-graph (LED display) : peak value, automatic zoom function in case of absence of modulation. DIGIPLEX configuration program : permit, in particular, the real time monitoring of the input signal and the Multiplex output signal. Power supply : Supply voltage : 115V/230V Voltage tolerance : +/-10% Supply frequency : 45-65 Hz Supply filter : yes Parallel protection unit : Gemov Fuse : 250mAT (230V) / 500mAT (115V) Power consumption : 25VA Mechanical aspects : Height : 1U (44,5 mm) Length : 483 mm Depth : 220 mm Net weight : 7 kg Environmental data : Temperature (operating) : 0°C to 50°C ambient Temperature (storage) : -30°C to 80°C ambient Altitude : 0 to 5000 metres Humidity : Class F, DIN50040 Labo CEM : Télédiffusion de France CEM : EN50022 and generic standards. Hardened immunity : 10V/m minimum


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Physical components and interfaces

The Digiplexer case

• Chassis : stainless steel. The chassis surface is conductive. • Upper panel : May be dismantled for access to internal components • Ventilation : Natural convection by upper and lower openings

Rear panel

▲ IMPORTANT : The « EARTH » pin of the IEC connector is connected to the chassis of the

Digiplexer. If the Digiplexer is not connected to earth, the potential difference of the chassis will

float : it is not recommended to use the equipment in this manner.

▲ WARNING : The equipment ground is close to the chassis potential : Therefore, ensure that

the equipment is connected to the earth via the IEC supply connector and not simply via the

ground of one of the XLR, SUB-D or BNC connectors used.

0 1

230V

(1) (2) (3) (7) (5)

(4) (6)

Power supply (IEC)

On/Off switch

115V/230V select


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(1) RF Output (option)

This output is only used for demonstration applications, factory use or for production lines of car

radios, FM tuners and receivers of all kinds. The Digiplexer is then used as a test generator.

For more information concerning this type of use, please contact AUDEMAT-AZTEC .

(2) "AES/EBU" digital audio input

Input for the AES/EBU signal. The signal to apply is symmetric, floating. A transformer assures

the galvanic isolation of this input with reference to the Digiplexer voltage. The AES/EBU input

is insensitive to the polarity of the applied signal.

(3) Symmetrical analogue audio input (left channel) (4) Symmetrical analogue audio input (right channel)

AES-EBU digital input XLR female connector

Pin Signal 1 Digiplexer Ground. It is advisable to connect

the screen of the cable used to this pin, if possible.

2 AES+.

3 AES-

Symmetrical Audio Inputs Female XLR connectors

Pin Signal 1 Digiplexer Ground. It is advisable to connect

the screen of the cable used to this pin, if possible.

2 Audio (-). This pin is to connect pin 1 (gnd) for an asymmetrical audio supply

3 Audio (+)


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(5) Input/Output synchronisation signal 19000 Hz / FM-SYNC This input/output is frequently referred to as « SYNC port » in this document. (6) Composite input Signal - Multiplex (asymmetrical) (7) Composite output signal - Multiplex (asymmetrical)

"MPX" Input / Output (asymmetrical) BNC connector

Pin Signal Central Synchronisation signal

Connector ground

Digiplexer ground

"MPX" Input BNC connector

Pin Signal Central Composite Multiplex Signal applied to the

Digiplexer Connector

ground Digiplexer ground

"MPX" Output BNC connector

Pin Signal Central Composite Multiplex Signal delivered by the

Digiplexer Connector

Chassis Digiplexer ground


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Front panel

"COM0" port RS232 (female)

AZTEC FMX410/440 DIGIPLEXER

10 digit alpha display

LED Bar graph deviation meter 2 push buttons

to move around the different menus and modify the Digiplexer

parameters.

Aztec Logo

FMX410 "COM0" RS232 PORT (female) Pin Signal

1 do not use 2 TX (DCE) 3 RX (DCE) 4 connected to pin 6 5 GND 6 connected to pin 4 7 connected to pin 8 8 connected to pin 7 9 do not use


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Internal composition of the Digiplexer

The figure below shows the electrical and electronic components of the Digiplexer.

Digiplexer FMX410

DSP PCB

Power supply PCB

Supply filter

Toric transformer 10 digit alpha display PCB


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FMX410 PCB : jumpers, points of adjustment

▲ IMPORTANT The adjustment of the stereo separation can be performed with the P2 potentiometer. The procedure is described in the AUDEMAT-AZTEC AZT1851_0_2. doc document. The adjustment of this parameter has to be done in the best possible conditions (care to cables, quality, impedance).

Potentiometer P1 power on bypass Gain: fine adjustment (+/- 0,3dB)

Jumper J22 1-2 : bypass active when power off. 2-3 : no bypass when power off.

3 2 1

321

Jumper J24 1-2 : bypass active when power on. 2-3 : no bypass when power on.

1 2 3

Jumper J23 Origin synchro 1-2 : input BNC "MPX" 2-3 : input BNC "SYNC"

DSPDSP DSP

DSPDSP

OPTI ON

MICROC.

Adjustable C189 Internal time base.

GAL

LED SYNCHRO Not lit : Digiplexer synchronised on external source Lit : Digiplexer non synchronised on external source


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CPURAM

CODE E2PROM

RS232 BUS

Digital Signal

ProcessorSynthesisMultiplexSTEREO

+ RDS

Limiter Clipper

Schematic

Multiplex digitizing Option

DA

PLL

Relay Relay

EXT

INT

J23 16bits

MPX input MPXoutput

COM0

Power supply system

+5V+15V-15V

Digiplexer FMX410

SYNC Input/ Output

Antialias.

Display

Level indicator

Buttons

Digital Multiplex Port

8-16Mbits/s

J24

J22

DA

Analogue audio inputs (L&R)

DA

Digital audio (AES-EBU)

DIG AES

Interface ports with RDS40 PCB

P1

C189

Gain

Gain


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About the Composite Multiplex signal The Digiplexer is a global and digital synthesiser of the composite Multiplex signal used in frequency

modulated radio broadcasting. This chapter presents a few technical components related to this

signal.

Multiplex signal composition

Contrary to the audio signal that normally occupies a frequency band of 20Hz - 20000Hz, the

multiplexing used in FM radio broadcasting today uses a frequency band of 0 - 100kHz.

In fact, the transmission of the stereophonic signal and of the additional subcarriers such as RDS

(RBDS for USA) is achieved by a frequency multiplexing of the different channels.

The reasons for this multiplexing are historic, stereophonic encoding uses a principle perfected in the

1950s. If the principle of stereophonic encoding has not changed since this era, its application has

followed the technological developments, as much in the level of multiplexing as in demultiplexing

(stereophonic decoding).

The stereophonic effect (L-R) is offset in frequency owing to the amplitude modulation of a 38kHz

sinusoidal signal by this stereophonic component (L-R). The absence of the 38000 Hz carrier is

explained by the fact that no dc component is present in the transmitted audio signal

Frequency

L+R (mono) L-RL-R

RDS 5%

Stereo Pilot

Amplitude

23 KHz 53 KHz 15 KHz

19 KHz 57 KHz 38 KHz 92 kHz

‘S’ channel

Note : 57kHz = 19 kHz x 3 38kHz = 19 kHz x 2


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The 19kHz subcarrier, or pilot, carries a temporal and frequencial reference signal used by the

stereophonic decoders, to demodulate the stereophonic effect (L-R).

The RDS signal obeys to the same kind of frequency translation, applying a slightly more complicated

AM technique, since it is seen as the combination of 2 modulating signals out of phase by 90°. The

extremely severe characteristics of synthesis prevent the RDS signal from overlapping the top of the

stereophonic component.

Other subcarriers sometimes profit from the FM spectrum, such as the SCA system (frequency

modulation at 67kHz) popular in the USA and in a few stations in Spain. This unit transmits a sound

signal (approx. 60hz - 8kHz pass band) for use in specific receivers (programmes for department

stores,...).

At last, multiple frequencies are used for the subcarriers : this precaution is essential to avoid the

noise resulting from intermodulating products "falling" in the LF domain, which are often generated by

medium quality FM receivers.

Levels and units used to describe the Multiplex signal

The levels and units used to express the magnitude of the Multiplex signal (frequency, amplitude)

often lead to confusion.

In fact, the confusion comes from the fact that the Multiplex signal frequency modulates the carrier

(HF) situated in the FM band (87.6 to 107.9 MHz) : the higher the Multiplex signal, the larger the

deviation resulting from the HF carrier.

The deviation of the HF carrier is expressed as a frequency unit as it is relative to the frequency of the

HF carrier : for example, when one talks of a transmitter that transmits at 97.6 MHz ’70 kHz deviation’,

this signifies that the amplitude or the level of the Multiplex signal applied to the transmitter provokes a

deviation of the HF carrier from 97.530 MHz to 97.670 MHz and at the ‘rhythm’ of the modulation

contained in the Multiplex signal.

Thus, we can say that the pilot subcarrier whose frequency is 19 kHz ‘deviates’ or ‘provokes a

deviation’ (intrinsic) of 8 kHz : in more technical terms, this means that the carrier frequency of the

97.6 MHz transmitter varies from 97.592 to 97.608 MHz at a rate of 19000 times per second.

The international standardisation has maintained to specify a maximum instantaneous deviation of 75

kHz of the HF carrier. This limit, fixed as reference, is frequently seen specified in % : 75 kHz

deviation = 100%.


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In USA one prefers to talk of injection levels which are normally expressed in % of 75 kHz : 100%

deviation corresponds to 75 kHz deviation.

▲ IMPORTANT in the rest of this manual, the ‘deviations’ or ‘injection levels’, which all represent the

same thing are expressed in kHz.

The table below gives as an example the standardised deviations (in kHz) for the STEREO or RDS as

well as their equivalent in %. For the Digiplexer, these deviations translate in output « level ».

Table : standardised or specified deviations and % equivalents

NOTE : AUDEMAT-AZTEC has organised the configuration of the Digiplexer Multiplex signal

deviation level so that it appears as clear as possible : the unit of amplitude of the Multiplex signal is

expressed directly in kHz by the Digiplexer.

The use of kHz as unit is one of the wonderful advantages that the Digiplexer brings by it’s global

synthesis of the Multiplex signal : the MPX output level of the Digiplexer must be determined at the

beginning, once and for all, as a function of the transmitter’s characteristics.

Typical

deviation

Max

deviation

Min

deviation

Multiplex Signal

as a whole

75.0 KHz

100 %

Pilot frequency 19

kHz

6.8 Khz 9.0 %

RDS signal

57kHz

4.0 KHz 5.3 %

8 KHz 10.6 %

1.25KHz

1.6%


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Principles of digital synthesis of the Multiplex composite signal The Digiplexer uses Digital Signal Processors (DSP) to perform the digital synthesis operations of the

signal.

The audio signal applied to the analogue inputs (or digital) is over-sampled by digital processing

(dedicated DSP) of the Digiplexer system frequency (approx. 500 kHz) : this extremely complex

operation, which consists of obtaining a high sampling frequency, is essential for a high quality

processing of a signal to be transmitted in FM. The audio signal is processed with the aid of digital

filters, owing to operations called ‘convolutions’. The ‘convolutions’ use parameter tables and the

modification of the contents of these tables has an effect on the following parameters :

- response curve

- pass band (typically 20 Hz - 15000 Hz) or other configurable limits

- ripple in the pass band

The AM operations (stereo L-R and RDS subcarriers) follow perfectly the mathematical equations

which describe the types of modulation. No approximation is made in the setting up of the algorithms

concerned, which operate on 24 bit at the system operating frequency (Fech close to 500 kHz).

The RDS signal is generated from the temporal equation of each RDS symbol, which spreads in time

over several thousand Multiplex signal samples. The direct use of the mathematical equation, assures

a faultless respect of the spectral characteristics imposed by the cosine filtering of the RDS signal (-86

dB at 2.4 kHz of the central RDS frequency which is 57 kHz).

All the (L+R), (L-R) signals modulated at 38 kHz, 19kHz pilot frequency, RDS signals are then added

respecting a weighting derived from the user configuration.

The phase criterion between subcarriers (19 kHz, 38 kHz and 57 kHz) is easily respected, since the

signals come from the same system clock.

The system clock, can be synchronised by an external source (19 kHz) thus making it possible to

synchronise several Digiplexer units between one another, and offer a synchronism of the multiplex

signal for FM synchronous applications for example.


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Advantages of global digital synthesis of the Multiplex signal

GLOBAL generation of the composite Multiplex signal...

▼ Elimination of cascading equipment each one carrying its own noise level

▼ Determination of the amplitude of the different components of the generated spectrum, with a single

unit of deviation (kHz).

▼ No more subcarrier synchronisation problems

▼ Multiplex synchronism assured owing to the synchronisation functions, ideal for synchronous FM

applications.

▼ No more impedance and level adaptation problems between different equipment.

▼ Mutual protection of the various subcarriers and sub bands. In traditional architectures, the

stereophonic decoders and Multiplex limiters often generated harmonics or undesirable components

outside of the useful band. This is not the case of the Digiplexer.

▼ Improved reliability

DIGITAL generation of the composite Multiplex signal...

▼ Elimination of the dispersion of the characteristics. No more level deviations between 2 tracks,

or doubts about the subcarrier levels.

▼ Parametric flexibility. The different amplitudes (audio tracks and subcarriers) are independently

adjustable, within realistic limits.

▼ Perfectly mastered filtering characteristics. Digital processing permits perfect prediction of the

result to obtain. As such, the constant ripple of the audio input filter characteristics in the 0-15 kHz

band may be specified and/or modified, as well as the cut-off frequency which can easily be

configured.


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Instantaneous deviation and power related to modulation The 75 kHz deviation limit is imposed in a quasi global manner by various regulations as regards FM

radio broadcasting. This is an instantaneous limit, i.e. this value of deviation may not be exceeded in

any situation, or at any time.

Certain radio stations are frequently measured as exceeding the 75 kHz limit by 20% without

necessarily, audibly, being aware of it. Inversely, one can often be surprised by the sound intensity of

a radio station and have doubts on their respect of the standards. Why ?

The deviation, alone, is not the only revealing parameter of acoustic level (audible) that the listener

can detect. In fact, if the deviation is an amplitude that describes a voltage or level, it does not

completely describe the notion of "power" or "density" of the signal.

The "power" of the composite or Multiplex signal is that which the listener notices. By associating the

time factor with deviation, we arrive at the notion of deviation power. The deviation power is the object

of today’s studies intending to be regulated : this project does not have a technical origin like the 75

kHz limitation but a desire to harmonise the audio signal power transmitted by stations to achieve a

comfortable listening quality.

Certain radio stations, whose opinion clearly opposes limiting the audio signal power, argue that

freedom on sound power is a marvellous instrument of differentiation between radio stations : the

sound of each station is different, and will remain different because it conveys subjective impressions,

which a power harmonisation would mostly eliminate.

The ability to strictly limit the deviation of the Multiplex signal to 75 kHz, has a direct effect in raising

it’s power, as, because of the presence of a barrier, the audio input level (that which comes out of the

mixing table or sound processing table) may be raised by 1 to 3 dB without risk of breaking the 75 kHz

bar.

The Digiplexer integrates this limiter function, which may be activated (11 preset adjustments) or

deactivated.

The "Multiplex Limiter " or " Multiplex Clipper " function

The concept of a deviation limiter or « clipper » has been controversial, as the placing of a composite

Multiplex signal limiter at the end of the audio and Multiplex chain have often the effect of destroying

the spectral quality of the signal delivered and of the integrity of the 19 kHz and RDS subcarriers .


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In fact, originally, a « clipper » was no more than a levelling function : the amplitude bumps passing a

given threshold are simply "shaved". Naturally, the result is catastrophic for the spectrum, as much in

the audio band as outside it where the pilot or RDS subcarriers were brutally amputated a fraction of

their signal, according to the aléas of the audio signal !

Since, substantial progress has been made by numerous French or American analogue equipment.

The levelling notion still remains present, but it only applies on the audio band and, an efficient filtering

(by rounding the ends) brings substantial improvements to the process.

The process used by AUDEMAT-AZTEC , even if it seems similar to the composite signal clipper

family and not to sound processing, has however an approach opposed to levelling. Owing to digital

processing, the Digiplexer knows perfectly how to anticipate in a given time T what the Multiplex signal

will be in T+∆T : it can therefore act on the processed signal, during ∆T (∆T not possible to listen to,

but long for digital processing = complex calculations and processing made possible).

AGC function

This function gives the possibility to dynamicaly adjust the sensitivity of the analogue audio input of the

Digiplexer. It regulates the level differences at the audio inputs, especially when no sound processing

equipment is connect before the Digiplexer. The Digiplexer allows the adjustment of the reaction

timings of the AGC. The effects of the AGC function are rather slow compared to the other functions

like the clipper, compressor or expender.

"ADDPWR" function

Based on the same principe of the Multiplex Clipper, it is possible, within the following limit (1 to 5 dB)

to digitally enhance the power of the Multiplex signal when the 75kHz limit is not reached, in order to

optimise the excursion to this previous value.

The function of enhancement of the Multiplex signal excursion has to be combined with the limiter, in

order to keep the 75kHz limit in all cases.


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The MPX LIMITER POWER FUNCTION

Description of the new commands Following commands have been included in the menu GOTOPROCESS of the 8 LED screen in the front side. They are also available in console or via HTML.

MPX Power limiter Activation: LIMITER=0 NO power limiter LIMITER=1 Hard forced Power Limiter LIMITER=2 Smooth forced Power limiter

LIMITER=3 Very smooth forced Power limiter

Maximum MPX power level expected in dB (0db by default): PWLVL=X.X 0<X.X<+6 dB (by step of 0,1 dB)

MPX power limiter action can be controlled via the 8 LED screen in front side after the deviation and MPX power display: L: OFF Inactive Limiter G:+12 A:1 Active Limiter with Gain (NMPA or NMPN)= 12dB and ADDPWR to 1 dB

Activation of the MPX Power Limiter 1/ PROCESS=1: Process in active mode 2/ ADDPWR=x: Set the Add Power function at x dB (0>= x >=6). This enables to manage an offset of Power augmentation of x dB above the expected MPX power level, without any deviation lost. 3/ Adjust the input gain (NMPA or NMPN), in order to obtain an average MPX level according to the program type and the expected MPX power level. 4/ PWLVL=x: Set the MPX power threshold level at x dB. (Above this value the limiter will act) 5/ LIMITER=1: limiter activation. Two-limiter regulation modes are available:

First one is Hard forced Power mode = maximum variation up to 0.4 dB/s (LIMITER=1)

Second is Smooth forced Power mode = maximum variation up to 0.1 dB/s (LIMITER=2)

Note: It is strongly advice to do not activate the AGC with the MPX power limiter.


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Example of procedure for using the FMX410 limiter 1/ PROCESS=1: Activate the processing mode 2/ ADDPWR=2: Set the add power function at 2 dB. It allows compensating for a 2 dB above set point increase in power, without deviation loss. 3/ Set the input gain so as to obtain an average level compared with the program type and the set MPX power. 4/ PWLVL=3: Set the power at 3 dB. 5/ LIMITER=1: Activate the limiter. Two limitation modes are available:

LIMITER 1: Mode with strong constraint control the power with gain variation as high as 0.4 dB par seconds.

LIMITER 2: Mode with low constraint control the power with a maximum variation of 0.1 dB par seconds.

Note: We strongly recommend not activating the AGC when using the MPX limiter.

Sub-carrier deviation

The deviation of the sub-carriers obeys rules as simple as those for the sound signal for the simple

reason that the average amplitude (or envelope) is not supposed to vary as a function of time.

▼ 19000 Hz "pilot" sub-carrier This is the case of the non modulated "pilot" sub-carrier , that is simply a 19000 Hz sinusoidal signal.

The amplitude of this sub-carrier is fixed by the standards, at 9% of the maximum deviation, thus

approximately 6.8 kHz.

There is no point in raising this value. In fact, the actual stereo FM receivers use this signal to the

maximum even when it is positioned at a considerably lower value. By default, the Digiplexer assures

a deviation of the pilot sub-carrier of 6.8 kHz.

▼ RDS sub-carrier signal This modulated signal presents a quasi constant envelope amplitude. The RDS sub-carrier deviation

level must be between 1 kHz and 8 kHz for a reasonable operation.

Contrary to the pilot sub-carrier, the deviation value of the RDS signal has a determining effect on the

behaviour of RDS car radios.


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A considerable signal level (more than 4 kHz) will have the effect of retaining a large number of car

radios on the received frequency : in fact, these car radios take into account the quality of the RDS

signal received to perform a frequency change.

With the RDS sub-carrier set between 3 and 4 kHz, the quality of the RDS signal is usually close to

that of the audio signal and the frequency switching is done at the moment where the listening quality

becomes subjectively precarious.

With the RDS sub-carrier set to less than 2 kHz, the car radio is prompted switch frequency when the

signal starts to show some little defaults in quality. Such a setting is useful when the broadcasting

network possesses a coverage where the transmitters considerably overlap one another

The Digiplexer takes 4 kHz as the default deviation value, for the RDS subcarrier. It is possible to set

this deviation level above 10 kHz.

Effect of the sub-carrier deviation on the global deviation

When the pilot and/or RDS sub-carrier are added, they modify the instantaneous deviation

accordingly.

Thus, a transmission without pilot sub-carrier, RDS and stereophonic effect would, in certain cases

(intense stereo effect), apply more than double the instantaneous deviation to the mono track (L+R)

than would the same stereophonic transmission with RDS.

Deviation SIGNAL

STEREO With RDS

STEREO Without RDS

MONO with RDS

MONO without RDS

RDS (kHz)

4

4

Pilot signal (kHz)

6,8

6,8

L+R (kHz)

32,1*

34,1*

71

75

L-R (kHz)

32,1*

34,1*

Global audio (L+R) and (L-R)

64,2**

68,2**

71

75

TOTAL (kHz)

75

75

75

75


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Table : Distribution of deviation between the different signals of a FM

stereo transmission in RDS.

* Indicates here a possible mean distribution but indicative arbitrary (example).

When the limiter (clipper) of the Digiplexer is activated, the Digiplexer, with it’s basic configuration

(mono/stereo, with or without RDS) will achieve a limitation at 75 kHz taking into account the levels

attributed to each of the sub-carriers (stereo and RDS).

The importance of sub-carrier synchronisation

Synchronisation of the RDS sub-carrier with the pilot sub-carrier is necessary.

If the RDS receivers never use the pilot sub-carrier (19 kHz) to perform RDS decoding, a lack of

phase relationship between the RDS sub-carrier (57 kHz) and (19 kHz) may generate pulsations of 0

to a few Hz, which can disrupt the RDS or stereophonic decoding.

When the Digiplexer provides RDS and stereophonic encoding at the same time, the synchronisation

between the 2 subcarriers is maintained implicitly and perfectly (without any variation or possible

phase noise). In this mode, it is useful to set the phase at 90° rather than at 0° : this arrangement has

the effect of reducing the combined 19 kHz + RDS deviation by about 10% and to diminish the effects

due to the phenomenon of audio intermodulation on old FM receivers.

When the Digiplexer is used as a stereophonic encoder, it is useful to set the "SYNC" input/output to

19 kHz "output" mode to supply the clock reference to an RDS encoder as master

When the Digiplexer is used as an RDS encoder, it is necessary to set the "SYNC" input/output to 19

kHz "input" mode (or in accordance with the case of the MPX input as reference input) to accept a

pilot signal and to synchronise to it.


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Digiplexer Installation and User’s Guide

Power supply

Check the value of the fuse at the back of the equipment (500mA) for 115V operation. Position the

jumper corresponding to the supply voltage.

The Digiplexer does not need to supplied via an UPS (Uninterruptible power supply) imperceptible to

power drops, it meets the requirements and thresholds considerably more severe than those required

in the European directive related to the electromagnetic compatibility of electronic equipment.

▲ WARNING Ensure that this equipment is directly connected to earth via the power cable and not

indirectly via the chassis, one of the communication ports or the GND of one of the BNC connectors

General installation layout of the equipment

▼ Physical location in a rack AUDEMAT-AZTEC has avoided the employment of forced ventilation for the Digiplexer, so as not to

penalise the product with potential mechanical problems. Thus, take care not to cover the openings at

the top and bottom of the product, which allow a natural circulation of air.

▼ Electromagnetic Compatibility The Digiplexer has been designed to be installed in FM transmission sites. Therefore, it meets

requirements and thresholds considerably more severe than those required in the area of the

European directive of electromagnetic compatibility of electronic equipment. Theoretically, no

additional component is to be added to the product.

▼ A few precautions to take when wiring the product The equipment’s RS232 ports are protected by means of 15V zener diodes mounted head to tail: this

arrangement makes the ports more robust. However, AUDEMAT-AZTEC strongly advise against

connecting on it’s ports, wiring coming from a local exterior to that where the Digiplexer has been

placed, ( possible large supply voltage differences, notably in the case of lightning strikes.


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Where to connect the incoming audio signal, Left, Right ?

Two types of inputs signals may be used, choose the input which corresponds to the format (digital or

analogue) used :

➫ "analogue" audio input

This input is presented in the form of two XLR connectors, one for the left track, the other for the

right track. Refer to the « Rear panel » paragraph of the « Physical components and

interfaces » chapter to know the pin-out of these connectors. Take care to respect scrupulously

the points mentioned in this paragraph concerning the use of these inputs in symmetrical or

asymmetrical mode.

« Symmetrical » mode : The incoming audio signal presents itself generally in the form of two

shielded cables, each one possessing 2 conductors, sometimes twisted.

« Asymmetrical » mode : The incoming audio signal presents itself generally in the form of two

shielded or coaxial cables, each one possessing only one central conductor.

The Digiplexer do not cancel the DC input levels. The use of isolating transformers is required

when the signal arrives on the transmission site via specialised lines : these isolating

transformers generally equip the equalisation of the parameters of the specialised lines unit.

The input impedance of the Digiplexer is 600 ohms, regardless of the mode used(symmetrical

or asymmetrical). This purely resistive impedance is made up of a 600 ohm resistor connected

directly between the positive and negative pins of each Digiplexer input.

NOTE : If the audio source with which you wish to supply the Digiplexer presents an

impedance considerably larger than 600 ohms, a consequent attenuation of the input

level will be observed. In this case, AUDEMAT-AZTEC advise the use of a line amplifier

in order to make the most of the Digiplexer’s characteristics. For experienced technical

departments, AUDEMAT-AZTEC can explain how to raise the impedance of the audio

inputs by removing two electronic components (SMT resistors close to the analogue

audio inputs).

➫ "Digital" audio input

This input is presented in the form of an XLR connector. Refer to the paragraph « Rear panel »

of the « Physical components and interfaces » chapter to obtain the pin-out of this connector.


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This port uses the AES/EBU format and supports a group of variants associated to this format.

the Digiplexer automatically knows each format variant and how to adapt itself to use the

maximum dynamic range of the audio signal (16 to 32 bit floating point).

▲ IMPORTANT : When the Digiplexer does not detect a valid signal at the terminals of its

digital audio input, the analogue audio input is used for sound broadcasting. During

digital audio use, the analogue audio inputs might be connected to an emergency

analogue audio input or left disconnected.

NOTE : The Digiplexer continuously analyses the digital audio input, and continues to

do so even when broadcasting is done from the analogue inputs. If the "AES" parameter

is set to 0 (AES=0), the Digiplexer will select the analogue inputs for broadcasting in

every case. When AES=1, the Digiplexer automatically opts for the digital input, if a valid

digital signal arrives on the AES_EBU input.

Where to connect the MPX output of the Digiplexer

The MPX output (composite Multiplex) is unique. It is asymmetric and must be connected to the input

of the FM pilot transmitter. The MPX output is asymmetrical and the use of a 50 ohm coaxial cable or

good quality shielded cable is advised to make this connection. This cable has to be as short as

possible.

The procedure for setting the MPX output level is part of a separate paragraph in this chapter.

The Digiplexer may, of course, be connected on another type of equipment other than a pilot

transmitter :

- analogue or digital multiplex beam

- RDS encoder

Understanding and choosing the « Bypass » function

The Digiplexer « Bypass » function is subtle and makes it possible to connect the product in the

majority of transmission architectures. The BYPASS function is to be considered in the following two

cases :


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➫ Power off BYPASS: determined by the position of the J22 jumper, the power off « BYPASS »

function when selected, passively relays any signal applied to the MPX input to the MPX

output. This function makes the « Digiplexer » transparent to the composite Multiplex signal

when it is switched off.

➫ Power on BYPASS : Determined by the position of the J23 jumper, the power on « BYPASS »

function relays the signal applied to the MPX input to the MPX output. The relaying is done

with a gain that can be configured by the command "GAIN=" and hardware refined with the

potentiometer P1 located on the Digiplexer PCB, close to the rear panel.

The following paragraphs give a non-exhaustive description of clever uses for the on and off BYPASS

function.

Installation of the Digiplexer with an external RDS encoder

When an external RDS encoder is preferred to the one which is integrated in the Digiplexer, the

configuration described in the figure below must be respected.

▲ IMPORTANT 1 : Check that the input level of the "MPX input" is set to "OFF", (GAIN=OFF) to avoid

any noise that could result from this port configured as input when the input is floating.

▲ IMPORTANT 2 : Configure the SYNC port in 19 kHz output mode (SYNC IO=O) and master mode

(SYNC=INT), so that the Digiplexer, delivers a 19 kHz synchronisation signal externally via this output.

There are 2 possible ways to synchronise of the RDS encoder :

➫ synchronisation by extraction of the pilot clock derived from the MPX signal

The « SYNC » port is not to be used in this configuration. Use this configuration if the RDS encoder

does not have an external synchronisation input.

➫ synchronisation by separate 19 kHz clock

The « SYNC » port is connected to the « SYNCHRO » input of the RDS encoder.

Do not forget to make the following hardware and software configurations :

23

FM pilot transmitter

MPX out

External RDS encoder

SYNC Port (mode "SYNCIO=O")

MPX in with ("GAIN=OFF")Digiplexer with external RDS encoder

Audio


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- jumpers J22 et J24 in mode BYPASS non activated

- jumper J23 : position immaterial

- set : "SYNC_IO=O"

- set : "SYNC=INT" (the Digiplexer generates the clock, master mode)

Installation of the Digiplexer with an external Stereophonic encoder

If an external stereophonic encoder is preferred to the one integrated in the Digiplexer, insert the

Digiplexer in the transmission chain as follows :


- jumpers J22 et J24 in mode BYPASS activated

- jumper J23 in position synchro by MPX input

- set : "SYNC_IO=O"

- set : "SYNC=EXT" (the Digiplexer receives the clock, slave mode)

- set : "AUDIO=0"

- set : "STEREO=0"

23


MPX out

External stereo encoder


MPX in ("GAIN=0, for example)

Digiplexer with external stereo encoder

Audio


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Installation of the Digiplexer with an external composite limiter

- jumpers J22 and J24 in mode BYPASS non activated


- set : "SYNC_IO=O"

- set : "SYNC=INT" (the Digiplexer provides the clock, master mode)

Installation of the Digiplexer as an emergency backup to existing equipment

In this mode, the Digiplexer is used as an emergency backup for equipment, intervening in the area of

the Multiplex signal generation.

Insert the Digiplexer just before the pilot transmitter. The Digiplexer BYPASS function will be

continuously activated. If a problem is noticed, the Digiplexer may be powered up by means of an

automatic unit or manually. Powering up the Digiplexer will provide the backup of the chain generating

the composite Multiplex signal.

23


MPX out

23

Multiplex Chain/line



MPX in

MPX out

Digiplexer maintaining the emergency backup of a Multiplex chain

The Digiplexer is powered up only when it must provide the backup function !

External MPX limiter

SYNC Port (mode "SYNCIO=O") MPX in

Audio

Digiplexer with external Multiplex limiter

Audio


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- jumper J22 in mode BYPASS activated (power off)

- jumper J24 in mode BYPASS non activated (power on)


- set : "SYNC_IO=O"

- set : "SYNC=INT" (the Digiplexer provides the clock, master mode)

-

To connect emergency backup equipment to the Digiplexer

In the same mind as the previous paragraph, use the « BYPASS » function to allow an emergency

Multiplex signal to go through the Digiplexer : simply interrupting the power to the Digiplexer will

provoke the emergency action.

To use the MPX input for the insertion of an SCA or additional signal

The MPX input allows any type of signal to be injected into the Digiplexer. The signal applied to this

input is affected a positive or negative gain (command GAIN=) ; the resulting signal is then added to

the output MPX signal on the condition that the jumper J24 is placed in "bypass activated power on".

This particularly interesting function allows the Digiplexer to accept any type of SCA, RDS, or other

subcarrier signal.

▲ WARNING 1 : The Digiplexer does not process the signal applied to it’s MPX input on the

frequency plan: this signifies that you must be in control of the spectral quality of the signal, which one

will be reflected at the output and counterbalanced with the gain fixed with the « GAIN= » command.

▲ WARNING 2 : In the same spirit, the deviation indication performed by the Digiplexer does not take into account the nature of the SCA (or other) signal applied to the MPX input!

To synchronise the Digiplexer by an external clock (19 kHz)

The Digiplexer can operate in slave mode, i.e. it can synchronise the hardware and software clocks on

an external clock: this function, allows the enslaving of a group of Digiplexers from a clock and offer a

cheap synchronism of FM modulation.


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In the « standard » equipment configuration, this clock has a frequency of 19000 Hz to establish

relations of synchronisation with the standard components intervening in the generation of the

composite Multiplex signal. AUDEMAT-AZTEC can adapt the Digiplexer internal software for other

clock frequencies on request.

In the case where the Digiplexer receives an external synchronisation signal, set up "SYNC=EXT"

(Digiplexer front panel or DIGIPLEX configuration software).

The « synchronisation » can be intervene by the MPX input, or by the SYNC port:

➫ Synchro via MPX input : extraction of the 19 kHz signal drowned in the multiplex signal

applied to the "MPX IN" input.

- configure J23 (origin synchro) in "MPX input" mode

- set SYNC_IO=O (a 19 kHz clock signal resulting from the synchronisation will be delivered

by the SYNC port).

➫ Synchro via SYNC port : use of a 19 kHz signal (of more than 100mVcc is advised, form

advised: sinusoidal) for the synchronisation of the Digiplexer

- configure J23 (origin synchro) in "input by SYNC port " mode

- set SYNC_IO=I : the SYNC port is used as an input

▲ WARNING : ensure the quality of the signal serving to synchronise the Digiplexer is satisfactory. To

do this, verify that the synchro LED (on the Digiplexer PCB) is not lit. (see representation of the PCB in

the paragraph « internal composition of the Digiplexer »).

To recover the Digiplexer clock reference (19kHz)

The Digiplexer is able to provide a 19 kHz signal +/-1 Hz, by it’s « SYNC » port, synchronous with the

transmitted pilot signal. To do this, make the following configurations :

- Jumper J23 : in position "MPX input"

- SYNC=INT : the Digiplexer provides synchronisation (Master mode)

- SYNC_IO=O : SYNC port in « output » mode

The delivered clock signal may be used to maintain FM synchronisation (synchronous FM).


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To adjust the nominal sensitivity of the Digiplexer audio inputs

This operation consists of adapting the input characteristics of the Digiplexer to the audio signal level

to be applied.

When the Digiplexer uses the AES/EBU digital audio input, the adjustment of the level applied to the

Digiplexer is done with the NMPN parameter.

When the analogue inputs are used (or likely to be used in case of an emergency) the setting of the

sensitivity of the analogue audio inputs is done with the NMPA parameter.

These adjustments are done from the front face or via the PC terminal application or the "DIGIPLEX"

configuration software.

For simplification, the purpose of the procedure of adjusting the sensitivity of the audio inputs is to

assign « the largest number of bits » of the audio signal that you are going to apply to the Digiplexer

input.

There are 2 ways to calibrate the analogue input level:

➫ « Theoretical » adjustment :

This type of adjustment may be done if you know accurately, to the nearest dB, the nominal

level of the audio signal that you are going to apply to the Left and Right analogue inputs The

nominal level is defined as being the level of the audio signal (400 Hz frequency) which will

produce a maximum FM deviation (75 kHz) in mono.

This level must be expressed in dB and represents the NPMA parameter :

Example 1 : The nominal level applied to the Digiplexer is +12dBu, configure NMPA=-12dB

(standard value configured at the delivery).

Example 2 : The nominal level applied to the Digiplexer is -6dBu, configure NMPA=-6dB.

➫ "Empirical" adjustment (most sure):

Inject an audio level which is considered as being representative of the maximum allowable

level into the Digiplexer.

Adjust the LVLI parameter until

- all the green LEDS of the bar graph display are lit

- the yellow led is at the limit of turning on, but not lit (corresponds to 75kHz)

- red LEDS never lit (not more than the nominal deviation)

- if the level shown is too high ☛ raise NMPA

- if the level shown is too low ☛ diminish NMPA


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in order to calibrate the digital input level :

the NMPN parameter is in dBfs (full scale) taken into account that 'full scale) is the maximum

value that can have a digital audio sample.

The most usual value is NMPN=-4dBfs (factory adjustment)

Please operate in the same way for the adjustment of the analogue inputs (2 methods) with

the NMPA parameter.

NOTE : these adjustments may be done without the Digiplexer connected to the pilot

transmitter.

To adjust the nominal output level (LVLO) of the Digiplexer

The purpose of adjusting the output level of the Digiplexer is to adapt the Digiplexer output

characteristics to that of the equipment which the Multiplex signal will be applied to: this is generally

an FM pilot transmitter or a hertzian beam feeder.

▲ WARNING : to perform these adjustments, it is imperative to deactivate all signal processing

functions (PROCESS=0).

➫ « Theoretical » adjustment :

Assign to the LVLO parameter (output LEVEL) the value of signal level (400 Hz sine wave)

which provokes an FM deviation of 75 kHz (mono without RDS and any other subcarrier) on

the pilot transmitter

The Digiplexer takes into account the pilot RDS and additional programmed subcarriers.

Negative and positive values are allowed for the « LVLO » parameter.

➫ "Empirical" adjustment :

◆ IMPORTANT : before making this adjustment, it is imperative to switch beforehand into the

desired FM transmission mode:

1 ➫ configure the presence or absence of stereo (STEREO=1 or STEREO=0)

2 ➫ adjust the pilot sub-carrier deviation to the desired value (LVL19=)

3 ➫ configure the presence or absence of RDS transmission (RDS=1 or RDS=0)

4 ➫ adjust the RDS sub-carrier deviation to the desired value (LVL57=)


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5 ➫ start the mode TEST1:L,R

6 ➫ Then adjust "LVL0" to reach the 75 kHz value indicated by a test receiver (e.g. RDS

Monitor or FM Navigator type). It is equally possible to use a spectrum analyser or

indication supplied by the bar graph or the vu-meter of the pilot used (on the condition

that one is certain of this measurement).

◆ IMPORTANT NOTE : the value LVLO has no incidence on the display of the

deviation value, or on the bar graph of the Digiplexer. The deviation values indicated by the

Digiplexer are not measurements and the precision of this indication depends on the

adjustment of the LVLO parameter.

In certain cases, it could be necessary to tune the input level adjustment of the pilot

transmitter, when it is possible, to achieve an optimal setting (to the nearest 0.1dB).

Reminders on the pre-emphasis function

The pre-emphasis function consists of increasing the high audio frequency levels in relation to the low

audio frequencies. The purpose of this is to reduce the signal to noise ratio by a proportion of 10 to

15dB by performing the inverse operation at the reception level.

The Digiplexer achieves the pre-emphasis operations in a purely digital manner, regardless of whether

the transmission mode is mono or stereo. Depending on the installation’s location in the world, set

P_EMPH=50 (µS) (EUROPE) or P_EMPH=75 (µS) (USA).

If the pre-emphasis function is achieved by external equipment, set P_EMPH=OFF to inhibit the pre-

emphasis function of the Digiplexer.

Monophonic transmission

Monophonic transmission consists of transmitting only the Mono track (Left + Right) and the RDS

signal.

To do this, set the « STEREO » parameter to 0 (STEREO=0). The Digiplexer will then digitally

suppress the following two signals :

- stereophonic effect (38kHz signal) suppressed.

- pilot frequency (19kHz) suppressed.


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The suppression of the pilot frequency permits the audio level to take a slightly more important part of

the deviation than in the case of a stereophonic transmission. The Multiplex limiter will, of course, take

this aspect into account.

◆ IMPORTANT NOTE : In the case of a monophonic transmission, it is imperative to supply the 2

Digiplexer inputs, either with a mono programme, or a stereo programme : the Digiplexer always does

the L+R operation. If the Digiplexer is only supplied in mono by one of the audio inputs, 6dB must be

subtracted from the setting value NMPA in order to compensate for the lack of signal on the other

input.

Stereophonic transmission

The stereophonic transmission consists of transmitting the two following signals in addition to the

mono signal :

- stereophonic effect (38kHz signal).

- 19kHz pilot frequency.

Configure STEREO=1 to place the Digiplexer in this operational mode.

To transmit the test signals

Several types of test signal may be transmitted by the Digiplexer at various possible frequencies. In

particular, they allow the calibration of the broadcasting channels. The table below shows the different

test signals that are obtainable with the Digiplexer

These test signals can be activated via the front panel, the ASCII protocol or the « DIGIPLEX »

configuration software.

◆ NOTE 1 : The transmission mode of the test signal is limited at 2 minutes. It must be reactivated.


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Test signal: TESTn:xxxx

xxxx ➫

n

L,R

L,-R

L,0

0,R

0

No test signal

No test signal

No test signal

No test signal

1

593,75Hz Left = Right

(mono)

593,75Hz Left = Right (L-R track)

593,75Hz

Left = 0

593,75Hz

Right=0

2

1187,5Hz Left = Right

(mono)

1187,5Hz Left = -Right (L-R track)

1187,5Hz

Left = 0

1187,5Hz

Right=0

3

14843Hz Left = Right

(mono)

14843Hz

Left = -Right (L-R track)

14843Hz

Left = 0

14843Hz Right = 0

◆ NOTE 2 : The test signals are always sinusoidal. The settings of the input sensitivity do not affect

the test signal. The deviation produced by the test signals is always 75 kHz.

◆ NOTE 3 : The test signals are transmitted respecting the configuration of the Digiplexer and the

level transmitted in this mode is automatically defined in such a way so that :

75,0kHz = {Audio level L+R} + {LVL19} + {LVL57}

The 593,75 Hz "L+R" test signal (TEST1=L,R) allows the Digiplexer output level to be calibrated : in

this mode the nominal output level « LVLO » of the Digiplexer can be adjusted so as to generate a

deviation of the carrier equal to 75 kHz on the pilot transmitter or the broadcast channel used.

See the setting procedure in the paragraph « To set the nominal output level of the Digiplexer » in the

chapter « Installation and user’s guide »...


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Multiplex processor operation (AGC, CLIP, ADDPWR, SEFFECT)

4 functions dedicated to Multiplex signal processing are implemented in the Digiplexer :

➫ AGC

This function gives the possibility to dynamically adjust the sensitivity of the ANALOGUE audio input

within a range of +6 to –6dB, depending on the analyse of the audio signal connected at the audio

input. This function can be set with the following parameters :

GATE threshold of the audio input level (below this threshold, the AGC function is frozen)

ATTACK : attack time at the audio input

DECAY : decay time at the audio input These parameters can be set either from the front panel (buttons and display) or with the DIGIPLEX software or with ACSCII protocol commands. ➫ CLIP

The Multiplex Clipper implemented in the Digiplexer is one of the most complicated function of the

equipment. Thanks to the AUDEMAT-AZTEC algorithms, the Digiplexer knows how to limit the audio

(L+R) and (L-R) multiplex signal in order to keep the 75kHz limit without any effect on the quality of

the audio signal (as long as the audio input level stays reasonable)

➫ ADDPWR

With a predictive algorithm, this function enhance the Multiplex power from 1 to 5 dB . This function

has to be associated with the CLIP function in order to keep the 75kHz excursion limit.

➫ SEFFECT

SEFFECT acts on the L-R part of the Multiplex signal and gives the possibility to reduce (SEFFECT=-

1 to –9) or to increase (SEFFECT=1 to 9) the stereo effect.

Note : these 4 functions can be activated or not activated with the PROCESS parameter of the

'Gotoprocess' of the front panel or with an ASCII command. Then, for activating at least one of these

functions, the condition PROCESS=1 is necessary.


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To modify the cut off frequencies on the audio tracks (L+R) et (L-R)

This function permits the individual adjustment of the high and low cut-off frequencies for each audio

band (L+R) and (L-R).

To do this, it is imperative to use the « DIGIPLEX » configuration software.

➫ Reduction of the pass band of the audio signal :

It is possible to reduce the high cut-off frequency of the signals L+R and/or L-R to eliminate

unwanted noise. Certain data transmission components buried in the audio signal use the

audio frequencies in the upper part of the pass band (ex : 14.9 kHz). The Digiplexer can be

configured to suppress this frequency by placing for example the high cut-off frequency at

14.5 kHz.

To save the current configuration in user memory

This function (SAVE>USER1 or SAVE>USER2) permits 2 different configurations, typical of the

Digiplexer, to be put into permanent memory and recall them at need. These configurations include

the following points :

- all RDS parameters (except for the FMX440)

- all Digiplexer parameters

To use the configuration in user memory for transmission

The functions « REST<USER1 », « REST<USER2 », « REST<FACTY» permit the Digiplexer to be

configured with the previously memorised parameters in the user memories.

The "factory configuration" may be recalled, by activating the function "REST<FACTY".


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To restrict access to the Digiplexer parameters

Access protection is achieved via the parameter « NKEY » which represents a secret code between 1

and 255. When NKEY=0, access is not restricted.

When access is restricted (NKEY<>0) :

- it is possible to visualise the parameters configured (via PC terminal or the front panel)

- it is not possible to modify the set up parameters

To access the parameters, the value of the « KEY » parameter must be modified to the value of the

secret code. The KEY parameter sets the value to "0" three minutes after the last action performed on

the front panel or the communication port.

If you forget the secret code, contact your nearest Distributor indicating the serial number of your

equipment : he will give you an unlocking code under certain conditions.

To personalise the welcome message of the Digiplexer (front panel)

If you do not use the welcome message to initialise a modem, it may be programmed to display the

(scrolling) message of your choice during power up of the equipment. See the protocol command

ASCII « WELCOME_TEXT= »

To use the Digiplexer with a Modem

By connecting a simple, commercially available modem to the FMX410 Digiplexer, it can be accessed

at any moment : all the Digiplexer parameters can be configured remotely and the input and output

level variations can even be observed.

You can connect a Modem to the COM0 port of the FMX410 Digiplexer. During power up of the

FMX410 Digiplexer, it can send a series of entirely configurable initialisation lines to this modem. 250

characters may be used for this purpose.

The ^M sequence of characters demands the Digiplexer to send a Carriage Return between 2

MODEM initialisation commands.

For any details, see the ASCII "WELCOME TEXT=" protocol command.


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Example: You would like the Digiplexer to call the number « 06.12.43.45.98 » each time it is powered

up :

Enter the following command : "WELCOME_TEXT=ATDT,0612434598^M"

Refer to the notice of your Modem to know the initialisation string required (HAYES commands).

For all the practical details, see the protocol command ASCII "WELCOME_TEXT="

The parameters are :

- automatic pick-up mode(HAYES standard command ATS0=0)

- serial port speed, modem Digiplexer link : fixed to 9600 bauds, see the SPEED command

- connection mode and speed

Connection cable DIGIPLEXER - MODEM :

DIGIPLEXER - MODEM connection cabling details

To display the composite multiplex output level

VALUE INDICATOR : The output level is given in the menu " _vvv.vkHz" in kHz: this only

reflects in a relative manner the level delivered by the Digiplexer to the FM pilot. This is why, it is

necessary to play with the LVLO parameter to precisely adapt the Digiplexer to the equipment (pilot or

beam feeder) to which it delivers the composite Multiplex signal. The LVLO value is expressed in dBu

and corresponds to the output voltage level when the display indicates " 75.0kHz".

SubD 9 male Digiplexer

SubD 9 male Modem

SudD 25 male Modem

2 3 2 3 2 3 5 5 7 connect pin 4 to 6

connect pin 7 to 8 connect pin 4 to 5

connect pin 6 to 20


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DEVIATION INDICATOR (BAR-GRAPH) The table below shows the behaviour of the bar graph, this

is only the image of the menu " _vvv.vkHz"

10 20 30 35 40 45 50 55 60 65 70 75 80 90 100 kHz

R1 V1 V2 V3 V4 V5 V6 V7 V8 V9 V10 V11 J R1 R2 R3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 kHz

The switching between the normal scale and the expanded scale is done automatically : the

first red LED "flashes" when the display is showing the extended scale, which allows the

observation of the subcarrier levels.

To display the predicted deviation (Multiplex signal) on PC

Use the "DIGIPLEX.EXE" configuration software : the evolution of the instantaneous multiplex signal

and Multiplex processing action (AGC, CLIP, ADDPWR) can be observed in graphic form.

The indicated levels are "unquestionable" and are not the result of the measurement: they are the

"peak" result of mathematical operations performed by the Digiplexer 500000 times per second.

BAR GRAPH : MULTIPLEX Display Multiplex output

" xxx.xkHz" Display Multiplex output " xxx.xkHz"

LED the signal passes... the signal passes... red lit = expanded scale not lit = normal scale

green n°1 1 kHz 10 kHz green n°2 2 kHz 20 kHz green n°3 3 kHz 30 kHz green n°4 4 kHz 35 kHz green n°5 5 kHz 40 kHz green n°6 6 kHz 45 kHz green n°7 7 kHz 50 kHz green n°8 8 kHz 55 kHz green n°9 9 kHz 60 kHz green n°10 10 kHz 65 kHz green n°11 11 kHz 70 kHz

yellow 12 kHz 75 kHz red n°1 13 kHz 80 kHz red n°2 14 kHz 90 kHz red n°3 15 kHz 100 kHz


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The displayed deviation is only "estimated" in the way that it’s accuracy depends on the setting of the

"LVLO" parameter and the characteristics (linearity and modulation) of the equipment driven by the

Digiplexer.

To display the predicted power (Multiplex signal) on PC

VALUE INDICATION : the power of the Multiplex signal is given in dB in the menu "PWRavv.vdB".

This value is continuously calculated with the digital sample of the Multiplex signal of the last

minute. The calculation is done on a scrolling window of 1 minute.

The Multiplex power can also be displayed with the DIGIPLEX software on a PC.

NOTE : the power displayed is only a "prediction", in fact the accuracy of the value depends of

the right adjustment of the parameter "LVLO" and the features (modulation linearity) of the

equipment controlled by the Digiplexer.

To display the action of the AGC function

VALUE INDICATION :

The gain or the attenuation generated by the AGC function on the analogue audio input is displayed in

the menu "AGC :av.v x". a=+ or -, X=G if the audio signal is below the GATE threshold, then the

function is frozen.

v.v shows the gain (applied at the analogue audio input) if a=+ or the attenuation if a=-

The action of the AGC function can also be displayed on a PC screen with DIGIPLEX software.

NOTE : the menu is displayed only if the function is active : AGC=1 and PROCESS=1.


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Automatical procedure for the analogue inputs calibration

With automatical "CALIBRATE" procedure the DIGIPLEXER calibrates its analogue inputs. This

procedure cancels any DC signal that would come from the existing analogue components. The noise

level at the analogue inputs is also analysed and an error message is displayed on the display

(exempla : "ERROR L NOIS" ) if an anormal level is detected : in this case contact your distributor.

IMPORTANT before launching the "CALIBRATE" procedure it is imperative to disconnect the

analogue inputs of the DIGIPLEXER. The "CALIBRATE" procedure can be initialised in 2 ways : ➫ with the front panel key buttons, in the ACTIONS menu

➫ with the ASCII command : <CALIBRATE>

◆ NOTE : this procedure is performed for each value among the 74 value of the NMPA (displayed on

the display), it takes approximately 5 minutes.


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To use the Front Panel

To use the display and the "SEL" and "OK" buttons

The display, the buttons and the bar graph on the front panel enable Digiplexer hardware to be

configured simply and quickly. Those who know how the AUDEMAT-AZTEC AZ1 RDS monitor

operates, will find one of the characteristics that made the product successful on the front panel of the

Digiplexer.

The two buttons must be manipulated independently. There are no subtle actions that require the 2

buttons to be pressed simultaneously.

The « SEL » button serves to move around a group of menus. The « ENTER » button serves to

modify the value of a displayed parameter, or perform the action proposed by the display. There are

three groups of menus :

➫ values and status display menu group

➫ parameter display and modification menu group

➫ action performing menu group

Concerning the parameters, the first touch on the « ENTER » button makes the "=" sign flash between

the parameter and it’s value : whilst the "=" sign is flashing, it is possible to modify the value of the

parameter by playing with each button « SEL » and « ENTER » which decrements and increments the

displayed value or index respectively. Before passing to another parameter, wait approximately 2

seconds for the "=" sign to stop flashing : the parameter has now been entered into memory.

NOTE 1 : when you use the configuration program supplied with the Digiplexer, AUDEMAT-AZTEC

recommend setting NKEY=0 during the use of the configuration software.

NOTE 2 : For simplification, the syntax used to display the parameters, their modification and the

performing of actions is compatible with those used by the ASCII protocol.

NOTE 3 : Display brightness : use the menu command ‘DISPLAY =‘ to adjust the brightness of the

10 digit display.

VERY IMPORTANT : The RDS parameters other than those influencing the RDS subcarrier (layer

1) are not accessible from the front panel.

FMX410 : use the configuration utility for Windows©, supplied with the Digiplexer, to set up the RDS

logic parameters ; the ASCII protocol can also be used.

FMX440 : see the manual (ref RDS19301).


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Welcome Messages on the front panel

Power up or Digiplexer RESET

To Display the parameters on front panel

** * *

AZTEC.....

DIGIPLEXER

...WELCOME

TYPE 410

RDS1545x

➫ Welcome message that appears on power up of the equipment or after a RESET. In all cases : ➫ TYPE of Digiplexer ➫ Version (VER:)

_vvv.vkHz

GotoParams

SEL button

➫ Predicted peak multiplex deviation level in kHz. See LED indicators at the end of precedent chapter

GotoAction

INP:xxxxxx ➫ Displays which audio source, "DIG" (digital) or "ANA" (analogue), the Digiplexer uses for broadcasting the sound signal. Displaying this function is useful when AES_EBU=1.

PARAMETERS:

See following pages

COM0:xxxxx ➫ For the Digiplexer FMX410 only, xxxxx=EBU to indicate that the active protocol on COM0 is the UER(EBU) SPB490 protocol, xxxxx=ASCII when the protocol is ASCII. When EBU=1, depressing the Enter key forces the Digiplexer to switch from one protocol to another.

RDS_TA:b__

ACTIONS:

See following pages

➫ Shows the state of the dynamic RDS parameter "TA", displayed in real time.

* not displayed for the FMX440 version

PWRaxx.xdB:➫ Multiplex Power in dB The calculation is done over a scrolling window of 1 minute.

AGC:ax.x_G ➫ This indication is displayed only if the analogue audio input is active and if PROCESS=ON and AGC=1. Ax.x indicates in dB the gain generated by the AGC function compared to the input level fixed with the NMPA parameter. 'G' appears at left when the audio level is below the GATE level

** this menu is present only if the analogue audio input is active and if PROCESS=1 and AGC=1


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Menus allowing the modification of the parameters

*

STEREO=b__

LVL19=kk.k

RDS=b_____

LVL57=kk.k

LVLO=sdd.d

SEL Key

ENTERkey

KEY=nnn___

NMPA=sdd.d

DATA=b____

NMPN=sdd.d

GAIN=ddd.d

PROCESS=n_

AES_EBU=b_

SYNC_IO=x_

P_EMPH=xx_

BYPASS=b__

SYNC=xxx__

SPEED=nnnn

TESTn=xxxx

ECHO=b____

➫ entering the secret code which allows the modification of parameters or to perform actions. This menu is present if a code has been programmed by NKEY=.

➫ Mono Mode (b=0) / Stereo (b=1)

➫ Deviation of the pilot subcarrier expressed in kHz. kk.k from 0.0 to 15.0 kHz

➫ Activates (b=1) or deactivates (b=0) the RDS subcarrier

➫ Deviation of the RDS subcarrier expressed in kHz. kk.k from 0.0 to 15.0 kHz

➫ Sets the nominal output level : sdd.d between -18.0 and 18.0 dBu for an excursion of 75kHz. sdd.d 'OFF' <=> inhibition.

➫ Inhibits (b=1) the transmission of RDS data whilst maintaining the subcarrier active. DATA passes automatically to 0 after 1 minute.

➫ Sets the nominal NMPA of the analogue audio inputs : sdd.d between -18.0 and +18.0 dBu or 'OFF' . see § <=> "To set the sensitivity of the audio inputs"

➫ Sets the sensitivity of the digital audio input: ddd.d between -10.0 and 0 dBfs or 'OFF'. More details: rf to paragraph "To set the sensitivity of the audio inputs"

➫ Sets the bypass gain of the MPX input to the MPX output : sdd.d including between -64.0 and +32.0 (dB) or 'OFF'.

➫ b=0 forces the analogue inputs to be used as audio sources. with b=1, the Digiplexer opts in preference for the digital input.

➫ n=0 No Multiplex Limiter, n=1 limiter only, n=2-6 CLIPPER +1 to +5dB; n=7-11 CLIPPER +1 to +4dB with reduction L-R

➫ Selects the type of pre-emphasis : xx=OFF for no pre-emphasis, xx=50 (µS) for Europe, xx=75 (µS) for the USA.

➫ Defines the sense of the SYNC port x=i for "input synchronisation", x=o for "output synchronisation"

➫ Defines if the Digiplexer provides the 19kHz clock in master mode (SYNC=INT) or if it must receive the external 19kHz clock (SYNC=EXT)

➫ Activates the BYPASS relay function (b=1) = identical effect to the Digiplexer POWERED DOWN. Normal operation : (b=0).

➫ TEST modes. For more details see the paragraph devoted to this mode: Chapter Installation and user’s guide...", pgph. "To transmit the test signals".

➫ Sets of the speed of the COM0 port: nnnn=1200, nnnn=2400 nnnn=4800 or nnnn=9600. Never any parity, always 1 stop bit. (FMX410 only).

➫ Activates (b=1) or deactivates (b=0) the ECHO on the communication port COM0. (FMX410 only).

The ENTER key modifies the value of the displayed parameter. During the modification, the "=" sign flashes rapidly. Depress the "SEL" key to record your choice.

HSS=b_____ This parameter cannot be used.

LVL76=kk.k This parameter cannot be used.

AUDIO=n___ ➫ Suppresses the audio signal (L+R) and (L-R). Useful when using the Digiplexer as a RDS or TSE SWIFT encoder without an audio output.

* *

* not displayed for the FMX440 version


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Menu allowing the adjustment of the PROCESS

* **

** ** *

* * * Ces menu are displayed only if PROCESS=1 ** Ces menu are displayed only if PROCESS=1 et AGC=1

Menus allowing the execution of actions

SAVE>USER2

REST<USER1

REST<USER2

REST<FACTY

SAVE>USER1 ➫ Stores the current configuration (broadcast) in the memory USER1

➫ Stock the current configuration in the memory USER2

➫ Assigns the whole of the parameters stored in the memory USER1to the current configuration (broadcast)

➫ Assigns the whole of the parameters stored in the memory USER2 to the current configuration (broadcast)

➫ . Assigns the whole of the factory parameters. to the current configuration (broadcast)

RESET ➫ Trigger hardware Reset of the Digiplexer

DISPLAY=n ➫ Display brightness, minimum for n=1, maximum for n=5

CALIBRATES ➫ Launch the calibration procedure for the audio analogue inputs. For this procedure, it is imperative to disconnect the analogue audio inputs.

@GATE=xnn_

@ATTACK=nn

@DECAY=nn

CLIP=nnkHz

@AGC=n____ ➫ n=1 activates the AGC function. The respective adjustments : @ATTACK, @DECAY, @GATE are accessible. If n=0, AGC is inhibited, the adjustments are hidden.

➫ x=+ or x=-, nn is in dBu. xnn indicates the threshold. Below this threshold the AGC function is frozen.

➫ nn=1 to 99. Reaction time to an increasing of the audio input level. nn=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB

➫ nn=1 to 99. Reaction time to an increasing of the audio input level. nn=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB

➫ nn=60 à 99 or OFF . Max value of the excursion. The Clipper will cancel all modulation peak which would generate an overtaking of this limit.

SEFFECT=ax ➫ a=+ or -; x=0 à 9. Si a=+, SEFFECT increase the stereo effect. If a=-, SEFFECT decrease the L-R part of the MPX signal from 10% if x=1 to 90% if x=9.

ADDPWR=ndB ➫ n=0 à 5. Increase of the Multiplex power of ndB. Note : ADDPWR is optimised for an operation with CLIP=75

PROCESS=n_ ➫ Activates (n=1), desctivates (n=0) the functions of the menu PROCESS : AGC, CLIPPER, ADDPWR, SEFFECT. If n=0 it inhibits the access to these parameters


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To use the Digiplexer via the ASCII protocol and COM0

To connect a PC to the COM0 port

To connect of a PC to the Digiplexer for configuration purposes, use the SUB-D9 connector located on

the front panel and labelled "COM0". Look for the communication port not used by your computer. If

the available port is presented in the form of a DB25 connector, use a standard SUB-D9 (male) to

SUB-D25 (female) adapter. Do not use the port used by the mouse. Connect the available

communication port of your computer to the port of the Digiplexer with a ribbon cable (non crossed),

preferably the one supplied with the equipment.

Choosing a "terminal" application and principles of the ASCII dialogue

To communicate as directly as possible with the Digiplexer, AUDEMAT-AZTEC recommend the use

of an ASCII terminal operating in MS-DOS© or Windows©. The DIGIPLEX configuration software also

integrates a "terminal" application which is simple to set up and use.

Terminal proposed for Windows© 3.x, Hyperterminal for Windows© 95 present all the characteristics to

easily communicate in ASCII mode with the Digiplexer. If you require a higher level terminal, refer to

the following chapter, which describes in detail, the installation of the AUDEMAT-AZTEC ®

configuration software for a very user-friendly configuration.

Windows© 3.X

In the Windows© programme manager, open the "accessories" group installed automatically with

Windows©. In this group, you will find the "Terminal" application, normally represented by an icon

containing a yellow telephone with a modem underneath interposed on a blue PC monitor.

Open the application. In the "Parameters" menu, select "Communications" and adjust the parameters

as follows :

▼ Transmission speed : 9600 on standard, otherwise, programme the same speed is for the

PC and the Digiplexer (SPEED=) with the help of the display and buttons.

▼ Data bits : 8

▼ Stop bits : 2

▼ Parity bit: None

▼ Flow control : None


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▼ Port : the available port you have used on the PC

▼ Parity control : don not tick the check box

▼ Carrier detection : do not tick the check box

Windows© 95

In the START menu, choose Program, then Accessories and open the file Hyper Terminal.

Launch the Hypertrm application et give a name, DIGIPLEXER for example.

Then select in « Connect» : « Direct to Com x » with x as the free communication port of your PC.

In the 'COMx property' window that appears, select :

▼ Bits per second : 9600 standard, otherwise care that you have the same speed

programmed for the PC and the DIGIPLEXER (SPEED=)

▼ Data Bits : 8

▼ Parity : none

▼ Stop Bits : 2

▼ Flux Control : None

Once the terminal has been configured, it is ready for use. To check if the hardware and logic

configurations function as planned, type "?" then <Enter> to display the Digiplexer general set up. If

nothing is displayed on the screen, try a second time, otherwise, check the following points :

➫ Is the Digiplexer switched on ?

➫ Cable

➫ Transmission speed of the Digiplexer (see menu "SPEED=" on the Digiplexer 410 display)

➫ Re check the configuration of the terminal application

For displaying on the screen the commands entered via the keyboard type the command "ECHO=1"

Before moving on to examine the numerous commands that are available, the structure of the

Digiplexer command interpreter is explain below :

The Digiplexer command interpreter meets the following rules. Any instruction sent to the Digiplexer

must be validated by <Enter>.

• Command without parameter (action) <name of the action> Ex: RESET <Enter> • Command with parameter < name of the action> = <value> Ex: TEST1=0,R • Assign a value to a parameter <name of the parameter> = <value> Ex: STEREO=1


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If a command entered leads to a process with success, the "+" character followed by one or several

line return characters is sent by the Digiplexer. If a failure occurs (command not understood or

incorrect parameter) the "!" character is sent under similar conditions.

The ASCII protocol command syntax is compatible with the syntax used for the display of parameters,

their modification and performing of actions by the front panel.

IMPORTANT: the processing of the protocol commands by the FMX410 Digiplexer and the

modification of the parameters by the front panel may be protected by a secret code (number

entered between 0 and 255, see protocol commands KEY= , KEY? and NKEY=).

When access to the Digiplexer is protected by a secret code, an error message is sent to any attempt

to modify a parameter.

IMPORTANT : the following paragraph and the following chapter describe the ASCII instruction set

of the FMX410 Digiplexer (hardware and RDS parameters) This set has been separated into two

parts:

➫ Instruction set to modify the hardware : compatible, with a few exceptions, with the menus

proposed on the display of the front panel).

➫ Instruction set modifying the RDS parameters. These instructions are only possible via the

ASCII protocol and only concern the FMX410 version. (See chapter « To use RDS with the

Digiplexer").

▲ WARNING : The FMX410 Digiplexer also supports the UECP (UER-SPB490) via COM0, used to

address RDS encoders. Details related to the coexistence of the ASCII and UECP protocols on the

COM0 port are given in the paragraph of this chapter relative to the switching between the ASCII and

UECP (UER-SPD490) protocols.

▲▲ WARNING : Do not send the ASCII characters chr$(254) or chr$(255), to the FMX410 Digiplexer

without reason, which in certain conditions, might switch automatically to the UECP (UER-SPB490)

protocol.


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The ASCII instruction set relative to the hardware configuration of the

FMX410 Digiplexer

ASCII instruction

syntax

Description of the ASCII instruction

FMX410 Digiplexer

? Display all the hardware parameters of the Digiplexer (those described by the instructions of this paragraph).

?? Display all the RDS parameters of the Digiplexer (those described by the instructions figuring in the chapter « Use of RDS by the Digiplexer ».

DISPLAY=n Adjust the brightness of the 10 digit display from minimum (n=1) to maximum (n=5). Value saved in permanent memory.

VER? Send the version of the Digiplexer internal software.

INP? Send "DIGITAL" if the digital input is used for broadcasting, "ANALOG" if the analogue inputs are used.

WELCOME_TEXT=

Xxxxx....xxxxx String of characters sent on the powering up of the Digiplexer FMX410 only. The message is sent to the following peripherals : On COM0 : the message written under WELCOME_TEXT is sent in place of the usual welcome message On the DISPLAY : the message written under WELCOME_TEXT is sent as well as the usual message. WELCOME_TEXT is useful as much for the personalising the equipment as for the initialisation of a modem at power up. The message may be erased by typing <WELCOME_TEXT=> without any additional string of characters. IMPORTANT: For each initialisation of a modem use the ^M syntax to specify the transmission of a Carriage Return, after each initialisation line.

TYPE? Send the Digiplexer type (FMX4nn).

KEY=v KEY?

v from 0 to 250

This system command is to be used to enter the secret code to unlock the write protection on the parameters stored in the Digiplexer’s permanent memory If the code entered corresponds to the Digiplexer’s secret code, it sends a "+" and opens access to the commands allowing the parameters to be modified. The unlocking remains active during 60 seconds after the last valid command entered into the Digiplexer. ▲ WARNING 3 failed attempts will make the Digiplexer "deaf" to any new command during 18 hours of operation. After this time, you will be given another three attempts. The "KEY?" command displays : 'KEYS NON ACTIVE : 3 trys' if the Digiplexer is locked with a code, 3 attempts remains for entering the code.


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ASCII instruction

syntax


FMX410 Digiplexer

'ACTIVE KEY' is the Digiplexer is momentarily unlocked but a locking code is programmed. ' ' (no reply) if no locking code is programmed. ▲ IMPORTANT If you have lost your secret code, contact your distributor who will give you a password to unlock it. See also : NKEY=

NKEY=v

v from 0 to 250

This system command defines or modifies the Digiplexer secret code. In order for this command to be active, the secret code needs to have been entered beforehand (KEY=<secret code>). NKEY=0 will inhibit the secret code function and make the Digiplexer permanently accessible : the Digiplexer is delivered in this condition. See also : KEY=

STEREO=bb=0 or 1

Defines the FM transmission mode, monophonic (STEREO=0) or stereophonic (STEREO=1). This parameter may be reread with the command "STEREO?".

LVL19=kk.kwhere kk.k is from 0.0

to 16,0

Defines the deviation level of the FM pilot subcarrier (19 kHz). The level is expressed in kHz and not in %. The parameter may be reread with the command "LVL19?".

RDS=b b=0 or 1

Activates (RDS=1) or deactivates (RDS=0) the generation of the RDS subcarrier. The parameter may be reread with the command "RDS?".

LVL57=kk.kwhere kk.k is from 0.0

to 16.0

Defines the deviation level of the RDS signal (57kHz). The level is to be expressed in kHz and not in %. The parameter may be reread with the command "LVL57?".

LEVEL=vv vv=0 to 1861

Defines the peak to peak output voltage of the 57kHz signal. This value is obviously linked to the output level of the DIGIPLEXER, it is only valid if LVLO=12 (output level = +12dBu). Note : this command interact with the command LVL57= LEVEL=465 <=> LVL57=4

PH57=xx where xx=0 or xx=90

Defines the relative phase of the 19kHz and 57kHz subcarriers (derived). The parameter may be reread with the command "PH57?".

DATA=b Where b=0 or b=1

DATA=0 inhibits the transmission of any RDS data and sends only successive "0"s. This transmission mode remains compatible with all RDS detectors that will detect and announce nevertheless the presence of a valid RDS "signal". DATA=1 transmit RDS normally. The DATA parameter is always reset to 1at the power up of the Digiplexer and after being set to 0 for more than 1 minute.

LVLO=sdd.dSdd.d from

Sets the nominal output level in dBu. Corresponds to a deviation of 75 kHz at f=400Hz in mono without RDS. The parameter may be reread with the command "LVLO?". Step : 0,5 dB


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ASCII instruction

syntax


FMX410 Digiplexer

-18.0 to +18.0 NMPA=sdd.d

Sdd.d from -18.0 to +18.0

Sets the input sensitivity. Example : set NMPA to 12 if the nominal signal level applied is +12dB. The parameter may be reread with the command "NMPA?". Step : 0,5 dB

NMPN=sdd.dsdd.d from 0 to -10.0

Sets the audio digital sensitivity input. "NMPN?" for reading the parameter. Step : 0,5dB. Usual value : -4dBfs (dB full scale).

GAIN=sdd.dSdd.d from

-64.0 to +32.0

Sets the bypass gain of the « MPX » input to the MPX output, unit = dB. The parameter may be reread with the command "GAIN?".

AES_EBU=b

b=0 or b=1

Forces (b=0) the analogue inputs to be used as audio sources. With b=1, the Digiplexer opts for the digital input when a valid digital-audio signal is applied. The parameter may be reread with the command "AES_EBU?"

P_EMPH=nnn=0, 50 or 90

Selects the type of pre-emphasis to apply to the audio signal : Europe xx=50(µs), USA xx=75(µs), No pre-emphasis xx=0. ). The parameter may be reread with the command "P_EMPH?"

SYNC_IO=nn=i (I) or n=o (O)

Defines the sense of the SYNC port, x=I (Input) for "synchronisation input", x=O (Output) for "synchronisation signal output". ). The parameter may be reread with "SYNC_IO?".

SYNC=xxx xxx=INT or xxx=EXT

Defines if the Digiplexer provides the 19 kHz clock in master mode (SYNC=INT) or if it must lock in phase with an external 19 kHz synchronisation signal (SYNC=EXT). ). The parameter may be reread with the command "SYNC?".

BYPASS=bb=0 or b=1

Activates the BYPASS relay function. Normal operation : b=0. The parameter may be reread with the command "BYPASS ?". B=1 identical effect to the Digiplexer powered off.


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ASCII instruction

syntax


FMX410 Digiplexer

TESTn=xxxxTEST=0 n from 0 to 4

xxxx= L,R or

xxxx=L,-R or

xxxx=L,0 or

xxxx=0,R

Test modes. For more details, see the paragraph devoted to the detailed description of this mode. « To transmit the test signals ».

SPEED=vvvvvvvv

=1200 or 2400 or 4800 or 9600

This command, only valid for the FMX410 Digiplexer, sets up the speed of the communication port. The parameter is stored in permanent memory. A change of speed occurs immediately after the receipt of the instruction.

ECHO=b b=0 or b=1

This command determines if the Digiplexer sends an echo(ECHO=1) of each character, or not (ECHO=0), that it receives by the RS232 interface when in ASCII mode.. ECHO=1 : the characters received are sent back by the Digiplexer’s COM0 port. When the Digiplexer has switched into " UECP protocol ", the parameter ECHO=1 activates the sending of a response to each UECP (UER-SPB490) protocol command received (MODE 2 of the UECP) See also : chapter devoted to the UECP (UER-SPB490) protocol commands.

PPRROOCCEESSSS==bb bb==00 oorr bb==11

b=1 allows the use of the function @AGC, CLIP, ADDPWR, SEFFECT. b=0 inihibits all these functions. When b=0 lthe acces to these functions via the menu GotoProces is impossible.

AAGGCC==bb bb==00 oorr bb==11

Activates (b=1), desactives (b=0) the fonction AGC. This function allows an automatical correction of the input level function of a measurement done on the signal input level. The operation of the AGC is defined with the parameters GATE, ATTACK, DECAY. This function grants an optimal result if CLIP=75. Note : the fonction AGC is active only if PROCESS=1

GGAATTEE==nn nn==--5500 ttoo nn==--1100

n defines the threshold of the audio input level below which the AGC function is frozen. This parameter avoids a growth of the audio signal level during an audio drop-out.

AATTTTAACCKK==nn nn==11 ttoo nn==9999

Defines a rection time for the AGC function during a growth of the input audio signal. n=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB

DDEECCAAYY==nn nn==11 ttoo nn==9999

Defines a rection time for the AGC function during a growth of the input audio signal. n=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99


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ASCII instruction

syntax


FMX410 Digiplexer

corresponds to 20s/dB

CCLLIIPP==nn nn==6600 ttoo nn==9999

oorr nn==OOFFFF

Defines the maximum deviation level. The signal is clipped by a digital signal process, in order to never overtake this limit. Note : the function CLIP is only active if PROCESS=1

AADDDDPPWWRR==nn nn==00 ttoo nn==55

This function allows, thanks to a digital signal processing operation, to densify the audio signal for increasing its 'MPX power' of n dB. This function grants an optimal result if CLIP=75. n=0 desactivates this function. Note : the function ADDPWR is only active if PROCESS=1

SSEEFFFFEECCTT==aann aa== -- oorr aa== ++

nn==00 àà nn==99

If a=+, SEFFECT increase the stereo effect. If a= -, SEFFECT drops down the L-R of the MPX signal from 10% if n=1 to 90% if n=9. n=0 inhibits this function. Note : the function SEFFECT is only active if PROCESS=1

PPRROOTTEECCTT==bb bb==00 oorr bb==11

b=1 activactes the protection of the Digiplexer configuration for the access via the Digiplex software. b=0 cancels all protection.

SAVE>USER1 Store the current configuration, including the RDS parameters of the FMX410 Digiplexer (broadcast) in the memory USER1.

SAVE>USER2 Store the current configuration, including the RDS parameters of the FMX410 Digiplexer (broadcast) in the memory USER2

REST<USER1 Assign all of the parameters (including RDS for the FMX410 Digiplexer only) stored in the memory USER1 to the current configuration (broadcast).

REST<USER2 Assign all of the parameters (including RDS for the FMX410 Digiplexer only) stored in the memory USER2 to the current configuration (broadcast).

REST<FACTYOr

INIT410

Assign all of the factory predefined parameters (including RDS) to the current configuration (broadcast),.

HELP Send back the instruction syntax essential to the ASCII protocol.


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To use the Digiplexer with the PC software supplied The Digiplexer is delivered with a diskette containing 2 configuration utilities operating under

Windows:

➫ "DIGIPLEX" configuration software

➫ Digiplexer RDS parameter configuration software

Place the diskette in drive A :

● In the Windows 3.x programme manager choose the option File and then Execute...

A:\INSTALL.EXE

or

● Click on the Start key for Windows 95, then choose Execute... A:\INSTALL.EXE

In the dialogue box that appears, choose the button "search...", select drive A. Type install.exe after

"File name", double click below and press OK in the "execute" dialogue window.

Follow the instructions that appear on the screen. 2 principle icons will be created:

- An icon with the RDS logo, corresponding to the RDS configuration utility

- An icon representing the Multiplex spectrum, corresponding to the Digiplexer configuration

utility

▼ NOTE : You may distribute and copy the software as much as you want, without the specific

authorisation of AUDEMAT-AZTEC.


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To use the « DIGIPLEX » software to configure the Digiplexer hardware

Broadcasts the Digiplexer’s test signal ; different signal frequencies, different modes (L,R,L+R, L-R).

Possibility to display the instantaneous peak to peak level and the signal Multiplex power generated by the Digiplexer. It also allows to display and adjust on the same curve the action of the parameters CLIP, AGC, ADDPWR and SEFFECT.

To leave the programme.

Access to the uploading function of the RDS40 board in its Flash memory. Allows the update of the firmware or the changes of the RDS40 board function : RDS ODA / RDS EPP.

General parameters of the Digiplexer (memories, users, password, selection and adjustments of the communication : RS232, INTERNET, Modem) Access to the utility software for the DSP's.

Configures all the parameters influencing the behaviour of the Digiplexer in relation to the physical signals (inputs, outputs) :rf following paragraphs.


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DIGIPLEX software : General set up screen (F2)

This menu performs the transfer of configurations between the Broadcast memory and the backup memories (MEM1, MEM2 and Factory). Simply slide one coloured element to another to initiate the transfer.

This window communicates directly with the Digiplexer by means of it’s ASCII protocol instruction set. Type the instructions in the OUTPUT window, the responses sent back by the Digiplexer are displayed in the INPUT window. It is possible to setup the communication speed and to clear the Digiplexer buffer (Clear input Buffer). "Force to ASCII Mode" switches the Digiplexer into ASCII mode, if the EBU protocol is activated ; the ASCII protocol retakes control after several minutes. ◆ NOTE : All the ASCII instructions supported by the Digiplexer, including that concerning RDS may be entered in this window.

Update of the DSP firmware : additionnal informations are delivered by AZTEC. ASCII terminal : open the ASCII window : see below. About AZTEC : displays the team of AZTEC with the associated names and phone numbers. Close ; close this window and returns to the main menu.

Choice of the communication mode : RS232, Modem or Internet and the password.

Seting of the IP address and the number of the logical port

Configure here the communication port of the PC. Test COM : checks which ports of the PC are likely to be free. Modem Configuration : acces to the modem configuration editor.


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Parameter configuration screen related to the signals used or generated by the Digiplexer (F3) .

Select here if the AES/EBU input must have priority (Digital/analogue) or not (Analog only) over the analogue input.

Subcarriers levels Pilot (LVL19) RDS (LVL57) and "High Speed " can be adjusted here.

When the « BYPASS » check box is activated, the BYPASS relay sends the signal applied to the Digiplexer input directly to the output. (BYPASS=1).

Download Digiplexer : read and displays the Digiplexer configuration. Upload Digiplexer : send the configuration to the Digiplexer Read data file: load and displays the configuration included in a file Save as: save the displayed configuration in a file of the hard disk of your PC.

To close this window.

NMPA : defines the nominal operating level of the analogue Digiplexer input in dBu. NMPN : defines the nominal operating level of the digital Digiplexer input in dBfs. LVLO : defines the maximum output level for 75kHz excursion. MPX gain : retransmission gain of a signal from the MPX input to the MPX output.

PH57 : defines if the relative phase of the 57kHz (RDS) signal is 0° or 90° in relation to the 19kHz sinusoidal pilot signal.

SYNC : defines if the Digiplexer 19 kHz clock is Master (INT) or Slave (EXT).

SYNC_IO : defines if the SYNC port is used as a signal input or output.

Selection of the different element of the Multiplex signal. Each element can be individually activated or desactivated

Select here the pre-emphasis mode (PRE_EMPH),

Selection of the configuration mode. By default, if the PC is connected to the Digiplexer, the mode of configuration is the connected mode : any modification done in this window is immediately sent to the Digiplexer. Action on this button initialise the disconnected mode, then the button diplays 'Disconnection'. The modifications are not transmitted to the Digiplexer. With this mode, you can work on a file.

Densification of the Multiplex power of the signal

Adjustment of the L-R part of the Multiplex signal.

Adjustment of the clipping function.

Setting of the AGC function Non activation threshold : GATE Audio attack time : ATTACK Audio decay time : DECAY


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Logiciel DIGIPLEX : generating signal test

DIGIPLEX software : Digital Multiplex signal display

▲ IMPORTANT : the displayed levels do not depends of the LVLO parameter. ◆ NOTE : the screen refreshing, and in consequence the delay between the audio signal and its picture depends of the processing capacity of your PC. The buffer gives an indication of this delay.

Broadcasts test signal with this window. With this button table, select the signal frequency combined with the type of the test signal. Activation of the test signal only for a temporary period.

Closes the window and returns to the main menu. Aknowledgement window is displayed if a test signal is active.

Indicates the active signal.

Indicates the action of the Clipper.

State of the PC input buffer.

Acces to : AGC, CLIP, ADDPWR and SEFFECT parameters.

Close this window and return to the main menu.

Indicates the action of the AGC function.

Value of the MPX power.


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To Configure the RDS parameters with the "FMB10CFG" software

(Windows©)

For more details concerning RDS configuration and the parameters, refer to the following chapter. The FMB10CFG program is installed automatically during the execution of the installation of the Digiplex set up program. To set up the RDS parameters by modem, use the ASCII terminal (ASCII protocol commands) integrated in the DIGIPLEX software, instead of this set up window.


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To use RDS with the FMX410 Digiplexer A few words about RDS

The RDS system is governed by the European standard CENELEC EN50067. This system has been

originally designed, to provide the functions directly associated with radio broadcasting and is briefly

described below :

▼ Automatic changing of frequencies

▼Display of the name of the station on the radio set

▼ Display of radio text for tuners

▼ Use of pre-select buttons on radios to memorise a station instead of its frequency.

The RDS system transmits the data via a 57 kHz sub-carrier. The reputation of the AUDEMAT-AZTEC

company is mainly due to it’s specialisation in the RDS domain which makes it a preferred supplier by

numerous public and private operators using RDS.

Over the years, RDS has been perfected and is used also for data transmission which has nothing to

do with the FM radio station ::

▼ Transmission of traffic data

▼ Paging system

▼ Remote control of units

▼ transmission of differential data for GPS

For simplification, the FMX410 Digiplexer provides the functions described first, but does not have the

large capabilities required to perform the functions described secondly.

Upgrading the FMX410 Digiplexer to the FMX440 Digiplexer is identical to upgrading the FMB10

encoder to the RDS FMB40 encoder by AUDEMAT-AZTEC : The RDS40 PCB (refer to the technical

manual RDS19301.DOC) needs to be added.


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ASCII instruction set for the configuration of RDS data : FMX410

ASCII instruction

syntax

ASCII instruction description DIGIPLEXER FMX410

Example(s) and comments

?? Display all RDS parameters of the Digiplexer (those described by the instructions figured in this chapter).

REST<FACTYor

INIT410

Assign all of the factory predefined parameters (including RDS) to the current configuration (broadcast),.

AF+=fff.f

AF- =fff.f

where fff.f is a frequency between 87,6 and 107,9

The command AF+= adds the frequency given as a parameter to the list of alternative frequencies (AF list). The command AF-= erases the frequency given as a parameter from the alternative frequency list (AF list). For more information on the use of the AF list by the receivers, refer to the relevant paragraph.

ASCII mode : the AF list can be reread with the command AF? The list is transmitted at approximately 6 frequencies per second. AF+100.7 no “:” missing AF+=100.7 yes AF+=100 no, the decimal must be specified AF+=100.0 yes AF+=096.8 no, no need for 0 at front of frequencies of less than 100 MHz. AF+=96.8 yes AF+=108.0 no, the frequency 108,0 is not in the authorised range. AF+=87.5 idem AF+=99.05 no, the frequency must be entered in steps of 0.1 MHz.

AF(nn) =ccc

where nn from 00 to 25 is the index of the AF

table ccc from 000 to 255 is

the AF code to be transmitted

This command permits to enter an AF table with the transmission format. See the CENELEC EN50067 standard for other details. It permits to transmit the AF with the method B with the total of 25 elements, but also to include the AF relative to AM frequencies. The AF table must always be ended by the code 0.

AF(1)=200 no AF(01)=200 yes AF(25)=2 no AF(25)=002 yes AF(35)=102 no 35 > 25 AF(10)=256 no 256>255

DI=v

v from 0 to 15

DI : Decoder Identifier used by the radio. DI represents the value of 4 bits according as the formula : DI = (b3 x 8) + (b2 x 4) + (b1 x 2) + b0 with :

ASCII mode: the DI parameter can be reread with the command DI? Normally, set DI=1 when the station transmits in stereo, set


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ASCII instruction

syntax



b0=0 monophonic transmission b0=1 stereophonic transmission b1=0 "non artificial head" b1=1 "artificial head" b2=0 "audio no compressed" b2=1 "audio compressed" b3=0 static use of the PTY b3=1 dynamic use of the PTY

DI=0 for mono. The RDS receivers do not seem to use this parameter.

EBU=0 or

EBU=1

Before using this command, please read the chapter devoted to the UECP (UER-SPB490) protocol commands ‘understood’ by the FMX410 Digiplexer. "EBU=1" activates the Digiplexer in a manner to be able to ‘switch’ the UECP (UER-SPB490) protocol after a certain time. See explaining paragraph. "EBU=0" : deactivates the processing of the UECP (UER-SPB490) protocol commands. See also : "ECHO=1" and chapter devoted to UECP (UER-SPB490) protocol commands ‘understood’ by the FMX410 Digiplexer.

ASCII mode: the EBU parameter can be reread with the command EBU?

G=bbbbccccdddd H=bbbbccccdddd

The commands "G=" and "H=" orders the FMX410 Digiplexer to send RDS groups whose contents are free. The RDS transmission can then be partially or totally controlled (at 100%) by an external application. "bbbb", "cccc", "dddd" represent the contents of the bloc B, bloc C, bloc D respectively in hexadecimal-ascii. The bloc A has not been specified as it is the PI code programmed with the command PI=. The H= command ignores the 11 most significant bits of bloc B « bbbb » entered and substitutes them according to the internal configuration of the parameters PTY, DI, MS, TA, TP of the FMX410 Digiplexer. The G= command ignores the parameters PTY, DI, MS, TA, TP programmed in the Digiplexer and broadcasts the bloc B

▲ IMPORTANT: to take 100% control of RDS transmission, do not forget to work at a communication speed higher than 2400 baud. (see SPEED=). Also, it is important to verify that the application that takes 100% control of the Digiplexer, waits for the "+" character followed by a carriage return, before sending a new command G= or H=. In all cases, the Digiplexer is the master of synchronisation, by transmitting the "+" indicating that it is ready to receive a new RDS group..


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ASCII instruction

syntax



« bbbb » as it was sent by the command G=. In all cases, the CRC is automatically calculated by the Digiplexer.

MS=0 or

MS=1

MS : Music/Speech switch MS=1 "music" mode MS=0 "speech" mode Rarely used by RDS radio receivers, it is nevertheless preferable to configure this parameter "MS" in agreement with the format of the radio station.

ASCII mode : the MS parameter can be reread with the command MS?

NPS=0 or

NPS=1

NPS=1 standard transmission mode of the PS code NPS=0 activates the "PS scrolling or revolving" function. In this case the transmitted PS code will be the Radio text message (entered with TEXT=) transmitted 8 characters by 8 characters at the rate of a few seconds interval between each block of 8 characters. NPS is saved permanently in memory. See also : RT=, TEXT=, paragraph devoted to « PS revolving or scrolling »

ASCII mode :the NPS parameter can be reread with the command NPS?

NUM=v v is between 0 and 255

This command may be used to attribute an identification number to the Digiplexer. The « NUM » parameter is also used when the Digiplexer has switched into UECP (UER-SPB490) protocol, and it corresponds to the site address of the Digiplexer as it is planned in the UECP (UER-SPB490) protocol.

ASCII mode: the NUM parameter can be reread with the command NUM?


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ASCII instruction

syntax



PI = h1h2h3h4

PI: Identification Code of the radio station (Program Identification) This RDS parameter contains 4 hexadecimal characters (h1h2h3h4 which are transmitted approximately every 100ms. h1 : country identification: "F" for France h2 : coverage identification "2" for national coverage. h2+h3: reference number of the station on a national or regional level. The code PI is attributed in France, by the CSA. See also : PS=

ASCII mode : the parameter PI may be reread with the command PI?, PI=F731 + yes PI=G731 + no "G" is not a hexadecimal character. PI=0000 + no 0 is not a valid country code.

PTYN = xxxxxxxx PTYN: clearly indicates the type of station as well as the PS code. (Program TYpe Name) This parameter always contains 8 ASCII characters (lower case and/or upper case) is transmitted in RDS at a speed depending on the value of the parameter PTYN_RATE. Used at origin in RBDS (USA). Adopted from now on in Europe. See also : PTYN_RATE=

PTYN_RATE = vv from 0 to 15

"PTYN_RATE=v" defines the number "v" of 0A groups inserted between 2 PTYN groups (10A type). v=0 : inhibits the broadcasting of PTYN groups. The lower the PTYN_RATE is, more the RDS resource will be accorded to the broadcasting of the PTYN parameter and the screen refresh rate of RDS posts will be faster. See also : PTYN=

FBT_RATE = v v from 0 to 15

The "FBT" function is only defined in the RBDS standard used in USA "FBT_RATE=v" defines the number "v"


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ASCII instruction

syntax



of 0A groups inserted between 2 groups Fast Basic Tuning (15A type). v=0 : inhibits of the broadcasting of FBT groups. The lower the FBT_RATE, the more will be the RDS resource given to the Radio Text and the screen refresh rate on FM Tuners will occur more rapidly.

PS = xxxxxxxx PS: name of the radio station that is displayed on RDS receivers. (Program Service) This parameter containing 8 ASCII characters (upper case and/or lower case) is transmitted in RDS at approximately 3 times a second.

ASCII mode the PS parameter can be reread with the command PS? PS=RADIO999 + yes PS=FRANCE3 + yes PS= A2 + yes PS=abcdefghi + no 8 characters maximum!

PST=v v from 0 to 3

This command is used to select other character tables to broadcast with PS and RT. For Europe and the USA : PST=0. For more details, refer to the RDS Standard EN50067.

ASCII mode : the PST parameter can be reread with the command PST?

PTY=v

v is between 0 and 31

PTY : Program TYpe PTY=0 type non defined PTY=1 news PTY=2 Affairs PTY=3 Info PTY=4 Sport PTY=5 Education PTY=6 Theatre & drama PTY=7 Cultural PTY=8 Science PTY=9 Programme varied PTY=10 Pop PTY=11 Rock PTY=12 MOR Music (middle of the road) PTY=13 "Light" classical music PTY=14 Classical music PTY=15 Other music PTY=16 Weather PTY=17 Finance PTY=18 Children's programmes PTY=19 Social Affairs

ASCII mode : the PTY parameter can be reread with the command PTY? The PTY parameter is transmitted at approximately every 350 ms.. A listener who possesses a tuner or advanced car radio, may if he wishes, perform a search according to a PTY criterion of his choosing. In practice, this function has not had much success in Europe, partially because of it’s limited aspect. However, it should be noted that programming PTY=0


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ASCII instruction

syntax



PTY=20 Religion PTY=21 Phone In PTY=22 Travel PTY=23 Leisure PTY=24 Jazz Music PTY=25 Country Music PTY=26 National Music PTY=27 Oldies Music PTY=28 Folk Music PTY=29 Documentary PTY=30 Alarm Test PTY=31 Alarm (warns that the program

broadcasts information concerning a danger for National order).

▲ IMPORTANT: the code PTY=31 is absolutely forbidden and its use is only recommended in the area of a national public programme.

does not mean that the station will be detected in all search cases : a listener making a search on « Classical music » will not finish on an RDS station programmed with PTY=0!

QUIT

This command leaves local mode and switches to (UER-SPB490) protocol if the parameter EBU=1.

RAZAF

This command erases completely the programmed AF list. See also : AF+=, AF-=, AF?

RT=0 or

RT=1

RT=1 causes the transmission of Radio Text (programmed with TEXT=). This transmission is done using type 2A RDS groups. RT=0 inhibits the transmission of Radio Text. When RT=1 the Radio Text is broadcast all the "RT_RATE" groups broadcast. RT-RATE is a parameter which allows the adjustment of the Radio Text transmission speed. See also : RT_RATE=, TEXT= ▲ IMPORTANT: when the FMX410 Digiplexer is driven as "slave" with a Radio Text transmission (ASCII PC commands of type G=2bbbccccdddd or H=2bbbccccdddd), it is recommended to inhibit the radio text coming from the Digiplexer (RT=0).

ASCII mode : the RT parameter can be reread with the command RT?

RT_RATE=v "RT_RATE=v" defines the number "v" of


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ASCII instruction

syntax



v is between 1 and 250 0A groups inserted between 2 Radio Text groups (2A type). This method implicitly defines a 0A and 2A group sequence. Their relative proportion may be therefore adjusted by RT_RATE. If RT_RATE is low, more RDS resource will be given to the Radio Text and the screen refresh rate on FM Tuners will occur more rapidly. See also : TEXT=, RT=

ASCII mode : the parameter RT_RATE may be reread with the command RT_RATE?

SAVE Save the TEXT= parameter in the permanent memory.

TA=0 or

TA=1

TA : indicator for the presence of traffic information during broadcasting. (Traffic Announcement). The value of the TA parameter is not written into permanent memory as it corresponds to an obligatory momentary event (few seconds, or a few minutes) IMPORTANT: The TA parameter may also be set at TA=1by an external switch connected to the logic input of the FMX410 Digiplexer. See also : TP= paragraph "What is the TA code for..." and the chapter "Physical components and interfaces"

ASCII mode : the parameter TA can be reread with the command TA?

TEXT= x1x2x3... x64

This command sets up a text (up to 64 characters) for broadcasting in Radio Text format. If not all the 64 characters are used, the FMX410 Digiplexer automatically adds spaces at the and of the entered text string. See also : RT_RATE=, RT=

the TEXT parameter may be reread with the command TEXT? ▲ IMPORTANT: if you wish to permanently save the entered text in memory with the TEXT= command, do not forget to execute the "SAVE" command.

TP=0 or

TP=1

b=0 or b=1 TP : indicator for the possibility of traffic information by the TA code. (Traffic Program). TP=0 signifies that the station does not intend to activate the TA parameter for the broadcasting of traffic information.

ASCII mode : the TP parameter can be reread with the command TP?


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ASCII instruction

syntax



See also : TA=

To set up the list of Automatic Frequencies to be transmitted

Certain receivers possess 2 HF receiver heads. Whilst one sweeps the FM band to search for the best

station, the other assures the reception of the signal for the listener. These types of receivers are

generally placed on top of the range car radios.

Other receivers regularly evaluate the HF signal level and if the latter is weak for a certain length of

time, the car radio interrupts the sound during about 0.25 seconds (decoding of the PI code attempted

+ measurement of the signal level) to select one of the frequencies it has in the AF list or list of last

frequencies used.

For certain car radio models, the length of the sound signal interruptions depend on the length of the

AF list : therefore it is better to put only the frequencies that are actually adjacent to the reference

transmitter (or RDS generator) into the list.

It is strongly advised to insert in the first place on the AF list, the exact frequency that supplies the

Digiplexer : this arrangement favours the behaviour of certain car radio models.

Note 1 : The FMX410 Digiplexer does not accept 2 identical frequencies in it’s list when the

frequencies are entered in ASCII mode with the command "AF+=". (use eventually the 'AF(nn)= ').

Note 2 : Method B is possible with the FMX410 Digiplexer on condition that the universal

communication protocol (SPB490) or the command 'AF(nn)= ' is used to enter the corresponding list.

Caution, only 25 AF members may be entered in the FMX410 Digiplexer, which reduces the number

actual frequencies for method B, to 12 !

To set up the PI and PS codes for the FMX410 Digiplexer

Certain car radios or RDS receivers convert the lower case characters transmitted into higher case

characters. The little standard ASCII codes (ASCII codes <32 for example) should be avoided as they

sometimes generate irregularities in the display on RDS receivers.


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Certain punctuation characters are sometimes not taken into account ("?",",","!"...).

The name chosen for the PS code must have 8 characters (including spaces), no more, and no less.

For this reason, do not hesitate to centralise short names.

To create a PS known as "revolving" or "scrolling" (FMX410)

AUDEMAT-AZTEC has maintained this function in the FMX410 Digiplexer even though it is rigorously

prohibited by the RDS EN50067 standard. See ASCII RDS protocol command : "NPS=0"

For information, there are 2 conflicting opinions on this subject :

• Prohibition of scrolling on the radio receiver: currently in force : it has been decided that by a large

majority to prohibit the use of « revolving or scrolling » PS for road safety reasons.

• Liberalisation of scrolling on the display of the radio receiver : Advocated by certain private radios

(Italy, France, Germany) this function animates the car radio display. The argument of safety (put

forward by the standard EN50067) is disproved by such stations who suggest that the on-board

navigation and map systems are likely to distract the driver considerably more than the scrolling of a

few characters on the display of a car radio.

AUDEMAT-AZTEC ’S opinion : as an industrialist being a member of working parties related to

the EN50067 standard, AUDEMAT-AZTEC is in favour of the prohibition of the revolving PS.

To set up the DI, PTY, MS codes of the FMX410 Digiplexer

Use the protocol commands associated "DI=", "PTY=" and "MS=". The paragraph devoted to the

explanation of the operation of these commands also describes them.

To set up the TP code (FMX410)

Set up "TP=1" when you contemplate switching the TA signal (Traffic Announcement).

As "TP=1", the car radio of the motorists who have selected the "TA/TP" function will stop on your

transmission.

For more details, see the set up instruction "TP=" in the instruction set offered by the FMX410

Digiplexer.


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What is the TA code used for, how does it work ? Switching the TA.

(FMX410)

Once the TP parameter is set to 1 (TP=1, with the instruction "TP=1") it is possible to remotely control

the CD drive or cassette player of the listener in order to temporarily interrupt it to broadcast the FM

programme, which contains the spoken information in direct relation with the traffic.

To perform this remote control action, there are two methods :

Hardware

Connect a switch to the COM0 port as indicated in the paragraph showing the pin-out of this

port connector. (rf chapter « Physical components and interfaces »).

Software

Use the "TA=" command of the ASCII protocol or use the UECP (UER-SPB490) protocol

command MEC03 to control the state of this parameter.

▲ IMPORTANT : Check that the TA parameter cannot remain unintentionally active, without

which, the listeners of the station will not be able to listen to their CD or cassette!

◆ NOTE : It is possible to display the state of the TA parameter on the front panel display,

with the Menu RDS_TA:b. (FMX410 only).

Radio Text transmission

The FMX410 Digiplexer permits the broadcasting of « static » or « dynamic » radio text.

Static Radio Text broadcasting:

The "TEXT="<64 text characters> instruction followed by the "SAVE" instruction memorises a text of

64 characters in the Digiplexer FMX410 permanent memory, which will be permanently transmitted in

a "static" manner. To do this, activate Radio Text static transmission with the RT=1 command and

adjust the text transmission speed with the command "RT_RATE=". The value RT_RATE=5 sends

approximately 8 characters per second, thus transmitting the 64 characters of text in approximately 8

seconds. (For more details see the protocol instructions in the corresponding paragraph).

Dynamic broadcasting of Radio Text ... 3 methods :

Instruction "TEXT=" not followed by the SAVE command. By sending this instruction, it is possible

to modify the transmitted text. There is no need to use "SAVE" because the transmissions of dynamic


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Radio Text are supposed to vary, for example in accordance with the title of the piece of music being

played.

Use the UECP (UER-SPB490) protocol with the corresponding command. In this case, activate the

Radio Text transmission with RT=1 beforehand, and adjust, also in advance, the transmission speed

with "RT_RATE=". For more details, see the UECP (UER-SPB490) protocol command on this subject.

If RT=0 and an UECP (UER-SPB490) protocol command is received, RT goes to 1 with RT_RATE=9.

Use the protocol instruction « H= » (H=2bbbcccddd) to transmit the type 2A Radio Text groups. For

more details, refer to the chapter on the standard RDS EN50067, referring to the group 2A structure.

To broadcast dynamic data

2 ASCII protocol instructions and a UECP (UER-SPB490) protocol command order the Digiplexer to

send free format groups to the FMX410 Digiplexer.

These instructions permit a micro-computer or external system to take 100% control of the FMX410

Digiplexer, via the RS232 interface and its ASCII protocol. This operation is particularly interesting for :

• simulations of RDS data broadcasting

• the transmission of TMC or dGPS data via RDS

• the transmission of RDS data

For this, see the instructions "H=" and "G=" in the paragraph devoted to the RDS instruction set of the

FMX410 Digiplexer or the « Free Format » command of the UECP (UER-SPB490) protocol.

To use the AUDEMAT-AZTEC "RDS-MCS" software to address the RDS

section

In parallel with their channels of high audio quality, the radio broadcasters have at their disposal, from

now on, data transmission channels which can be put to use in RDS services at least in the

maintenance of Digiplexer configurations.


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• Remote control of Digiplexers for the purposes of maintenance:

For the RDS section, the Digiplexer behaves like a standard RDS encoder. The

"RDS-MCS" program integrates the control of a group of RDS encoders of several

hundred units by different manufacturers. Each configuration is saved in a set up file.

Each RDS encoder can be individually and entirely reprogrammed at distance.

The encoders may also be addressed in a collective manner for the modification of

the PS code for example.


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ASCII and UECP (UER-SPB490) Protocols

The FMX410 Digiplexer contains 2 command interpreters :

• Interpreter for the ASCII protocol (FMX410 Digiplexer)

Allows communication with the Digiplexer with a terminal type application or hardware.

The command entered is an ASCII type command, it’s validation is done by a ‘carriage

return’ (chr$(13)+chr$(10)).

• Interpreter for certain UECP (UER-SPB490) protocol commands

These commands permit the FMX410 Digiplexer to be driven by means of standardised

commands. The FMX410 Digiplexer regroups only the functions essential to RDS, the

command set allowed by the equipment exists accordingly.

It is possible to set up the FMX410 Digiplexer in such a way that it accepts or not the UECP (UER-

SPB490) protocol commands. This set up is always done by via logic, using the command "EBU=".

The switching of the UECP (UER-SPB490) protocol

NOTE : this paragraph does not just apply to the FMX410 Digiplexer and the UECP (UER-

SPB490) protocol commands that it accepts. The FMX440 Digiplexer supports this protocol in a much

larger manner. For this, refer to the technical manual RDS40 (ref : RDS19301.DOC)

To control the FMX410 Digiplexer by remote, it is possible to set up the equipment so that 4 minutes

after power up, it accepts the UER (SPB490) protocol as means of control.

Thus, when the internal EBU parameter of the FMX410 Digiplexer is equal to 1 (protocol command

EBU=1), the Digiplexer remains in a state known as "LOCAL" during 4 minutes with the ASCII mode :

In the LOCAL state, the user may use his terminal to set up the Digiplexer.

At each set up command accepted positively by the FMX410 Digiplexer, a delay of 1 minute is

accorded before the equipment switches into UECP (UER-SPB490) protocol.

NOTE : to avoid waiting to the end of this delay, use the « QUIT » command. See ASCII protocol

commands relative to the RDS configuration of the FMX410 Digiplexer, previously in this document. It


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is also possible to send a field of UECP (UER-SPB490) protocol to avoid waiting for the end of this

delay.

Once the delay of the "LOCAL" mode has passed, the FMX410 Digiplexer goes into UECP (UER-

SPB490) protocol state.

Returning to the "LOCAL" state is possible with one of the following actions :

➫ an ON/OFF cycle

➫ pushing on the Enter key when the 'COM:EBU' menu is displayed

➫ RESET via the Actions menu

To set up the FMX410 Digiplexer permanently in LOCAL state, simply set the EBU parameter to 0

(protocol command ASCII : EBU=0) during LOCAL mode,.

Layer 2 communication protocol and timings requirements

The serial port (8) is used for data input for the High Speed Subcarrier.

Serial port configuration: 19200, N, 8, 1

Protocol: The Digiplexer requires the data to be preformatted in frames ready for layer 2

transmission. The BIC, CRC14 and horizontal and vertical parities are calculated by the Digiplexer, so

the data input is limited to the useful data. The frame type for data transmission must also be sent for

each input frame.

Digiplexer to Server: <ACK>

06Hex

Server to Digiplexer: <FRAME TYPE> <----DATA---->

00Hex FRAME A0 4180 bytes data

01Hex FRAME A1 4444 bytes data

02Hex FRAME B 4180 bytes data

03Hex FRAME C 5984 bytes data


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Timing requirements: Frames A0 and A1: The Digiplexer sends the <ACK> at the beginning of transmission of the parity

blocks.

Frame B: The Digiplexer sends the <ACK> at the beginning of transmission of the previous

transmitted frame. Data must be input at least 2.5 seconds before transmission

as Frame B requires that all horizontal and vertical parities be calculated before

the 16th block of the frame is transmitted.

Frame C: The Digiplexer sends the <ACK> at the beginning of 190th block.

RDS control differences between the FMX410 Digiplexer and the FMB10

Encoder

➫ RDS /RBDS : The RBDS switch no longer exists. Only the FBT remains a function specific to the

RBDS (USA)

➫ PS1/PS2 : function deleted as rarely used.

➫ Configuration with a Minitel : The Digiplexer is not configurable by Minitel as the major part of

these functions can be realised from the front panel.

➫ all the RDS parameter can be stored : the memories USER1 and USER2 can contain all the

configuration parameters of the FMX410 Digiplexer, including the RDS parameters.

➫ the LEDs : are replaced by the 10 digits display.

➫ remote control possibility with a Modem


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EXTENDED RDS : The FMX440 Digiplexer

As the Digiplexer schematic shows, the RDS40 PCB may be installed in the FMX410 Digiplexer to

give it extended RDS functions. The addition of this PCB must be done by AUDEMAT-AZTEC or one

of it’s distributors. This operation occurs either before delivery of the Digiplexer, or afterwards. In the

latter case, the FMX410 Digiplexer must be returned or intervened on site, in order to transform it into

a Digiplexer FMX440.

DIGIPLEXER FMX440 = DIGIPLEXER FMX410 + RDS40 extension board

The RDS40 PCB gives the FMX410 Digiplexer memory and communication couplers providing RDS

broadcasting functions considerably more complex than the basic functions provided by the FMX410

Digiplexer.

• Totally reprogrammable: The upgrading of the Digiplexer FMX440 internal RDS software is

done by means of a PC (portable) and the diskette containing the new programme no need

to open the Digiplexer, or change an EPROM, or even to stop to perform an upgrade !

• broadcast of EON information • Normal paging • EPP type paging(this licence is proposed as an option) • A FIFO and/or cyclic buffer for each type of RDS group • an extended compatibility with the EBU SPB490 protocol • ODA Open Data Applications data transmission • an RDS decoding function and transmission of alarm by relay • selective retransmission of RDS data from the MPX/RDS input • 2 additional communication ports • An additional RDS output • An RDS input for complex retransmission requirements

▲ WARNING : The RDS set up operation of the FMX440 Digiplexer is largely more complex than that

of the FMX410 Digiplexer. This operation is to be achieved either with the UECP (UER - SPB490)

protocol commands figuring in this chapter, or with the CODHEX.EXE software (file loading) or with

the AUDEMAT-AZTEC MCS2 software.


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Frequently Asked Questions (FAQ)

This chapter is updated every time you contact AUDEMAT-AZTEC and ask a question whose

response does not appear evident in this manual.

What is the relationship between the actual RDS level and that defined in the

UECP (UER-SPB490) protocol ?

The RDS level defined in the Digiplexer is in fact a deviation in kHz. The UECP protocol describes the

level in mV. It is imperative to specify that the Digiplexer converts the voltage parameter to an

excursion. The programmed level corresponds to the real output level of the DIGIPLEXER in the case

if LVLO=12dBu (valid for the FMX410 and FMX440 Digiplexer).

Example : LEVEL=465mV gives an RDS sub-carrier with an excursion of 4 kHz.

LEVEL=465 <=> LVL57=4

What is the relationship between the actual RDS phase and that defined in

the UECP (UER-SPB490) protocol

The relative phase of the 57 kHz and 19 kHz signals must be 0° or 90° after the RDS standard

(CENELEC EN50067). To this effect, the Digiplexer, integrating the RDS encoder and the Stereo

encoder accepts only 2 values of phase difference.

The Digiplexer therefore does not accept via the UECP protocol, 0° or 90° as the correct value of

phase difference.

Why doesn’t the LVLO level react on the bar graph display ?

LVLO represents only the parameter that adapts the Digiplexer to the transmitter that it drives. The bar

graph indication does not change in accordance with the LVLO value. The LVLO parameter must be

adjusted so that the transmitted deviation corresponds to the Digiplexer bar-graph indication.


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Does the Digiplexer allow DC components to pass ?

Yes, when the audio input used is the AES/EBU input. These DC components must be eliminated at

source in order to avoid for example an undesirable 38 kHz modulation due to the DC voltage

between the Left and Right tracks applied via the Digital AES.EBU input.

The first character of the displayed PS fluctuates on certain car radio

receivers

Check the value of the RDS parameter PST is 0. When PST is different of 0, a code signalling the use

of a special character table (defined in the CENELEC EN50067 standard) is transmitted with the first

character of the PS code. Certain receivers does not take into account of this particular case could

display a character at the reception of this code.

digiplexer fmx410 user manuel - radikal elektronik · 2008. 6. 23. · the operational blocks of...

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