cushman electronics ce-70 frequency selective levelmeter ~ operation manual, 07-1976

I,

OPERATION MANUAL

CE-70

FREQLIENCY

SELECTIVE

LEVELMETER

APPLICABLE TO INSTRUMENTS

WITH SERIAL NUMBERS 206

AND ABOVE. 7-78

MODEL CE-70

FREQUENCY SELECTIVE LEVELMETER

OPERATION MANUAL

JULY 19765601"0062

WØCCW

EFFECTIVE DATE: APRIL 1, 1977

CUSHMAN INSTRUMENT WARRANTY

All instruments manufactured by Cushman Electronics, Inc. are warranteed against defects in material and

workmanship for a period of one year from the date of original shipment. Cushman will repair or replace

instruments, which prove to be defective, in accordance with the following policy. This policy does not

apply to repair service, parts sales, nor does it apply to instruments, or parts of the instrument, which in

the opinion of Cushman, have been altered or misused.

All Countries

• During the first three months after the date of original shipment, no charge for parts, replacement PC

boards, labor, or freight for instruments serviced at an authorized Cushman Service Center. Free freight

applies onl y within the customer's cou ntry. Method of tra nsportation shall be designated by an authorized

Cushman representative or Service Center.

• During the fourth through the twelfth month after the date of original shipment, no charge for parts,

replacement PC boards, and labor for instruments serviced at an authorized Cushman Service Center.

All transportation charges for instruments, parts, or replacement PCboards shall be paid by the customer

during this period.

• Replacement PC boards during the first year are war ran teed only when the defective boards have been

identified by an authorized Cushman Service Center and the defective PC board is returned in accordance

with Cushman's exchange board pol icy.

U.S.A. and Canada

In the U.S.A. and Canada an additional two year limited warranty is offered extending from the 13th until

the 36th month from the date of original shipment. This warranty is effective beginning with instruments

purchased on or after April 1, 1977. During this period, the following limited warranty policy applies:

• No charge for parts· used by an authorized Cushman Service Center to repair an instrument.

• Cushman will replace at no charge, PC boards which are found to be defective by an authorized Cushman

Service Center. Defective boards must be returned to Cushman in accordance with Cushman's PC board

exchange policy.

• All transportation charges for instru ments, parts, and replacement PC boards sha II be paid by the

customer during this period.

• Cathode ray tubes and batteries excluded.

5 man Electronics, Inc.

CUSHMAN OPERATION MANUAL CE-70 JULY 1976

MODEL CE-70

FREQUENCY SELECTIVE LEVELMETER

CONTENTS PAGE

1. GENERAL.

2. DESCRIPTION 3

OPERATING FEATURES 3

PHYSICAL DESCRIPTION 3

CHARACTERISTICS 3

OPTIONS AND ACCESSORIES 3

3. PREPARATION. 11

UNPACKING AND INSPECTION 11

POWER REQUIREMENTS 11

GROUNDING REQUIREMENTS 11

WARM-UP REQUIREMENTS 11

4. CALIBRATION . 11

5. MEASUREMENTS 12

COMMON PROCEDURES 12

FREQUENCY RESPONSE MEASUREMENT USING BFO OUTPUT 12

OPERATING NOTES 13

SINGLE FREQUENCIES (PILOTS, CARRIER LEAK AND TEST TONES) 13

SINGLE FREQUENCY IN dBmO 14

SPURIOUS TONES IN TERMS OF dBrn AND dBrnO 14

TONE LEVEL ON SSB CHANNELS 14

CONTENTS PAGE

5. MEASUREMENTS (Cont)

FLUCTUATION NOISE IN dBp, dBrnC, dBrnCO . . 14

SPURIOUS SIGNALS 15

NOISE POWER RATIO (NPRI 15

PHASE JITTER . . 15

BRIDGING PROBE. 16

REPAIR SERVICE . 16

PREPARATION FOR RESHIPMENT. 16

1. GENERAL

1.01 The Cushman CE-70 Frequency Selective Levelmeter, Figure 1, is specifically designed

for maintenance of FDM multichannel carrier systems of either the land line or radio services. It has the capability of measuring signals, noise and frequency over the range of 1 kHz to 25 MHz. This extended frequency range makes the CE-70 suitable for testing high density systems including Bell Systems LMX-1, LMX-2, LMX-3, L-Carrier systems, L1, L3, L4, Coax and TD-2, TH-1, TH-3 radio multiplex systems.

1.02 A frequency synthesized tuning system is controlled by digital Frequency Selector

dials which may be set to the desired frequency with 10 Hz resolution. A search mode provides "continuous" tuning. This covers the full frequency range in either 10 Hz, 100 Hz or 1000 Hz steps. Since the Local Oscillator frequencies are generated by a frequency synthesizer which is referenced to a very stable crystal oscillator, measurements are stable and drift is nearly eliminated.

Printed in U.S.A. Page 1 5601"0062

COM CE-70

\n."I...~I"· ~d"."""'-,.".. .""

Figure 1. Model CE-70 Frequency Selective Levelmeter

(600 ohm jacks shown in photo is original configuration. See Figure 2 for later arrangement using a single W.E. 310 jack.!

1.03 The Level measurement range is from +10 to -109 dBm at 0 dB on the meter

(+10 to -90 dBm in TONE and -10 to -109 dBm in NOISE mode). To this may be added the meter range of +2 dB to -20 dB. The meter also has a i 1 dB expanded scale so that scale readings may be resolved to .05 dB. Overall level accuracy is iO.15 dB to -69 dBm to 18.6 MHz. Operation in the EXP mode is signalled by a front panel indicator light.

1.04 The CE-70 may be used with equipment or systems having anyone of four standard

impedances, 75n, 124n, 135n, or 600n. The impedances are switch selected. As an option 150n is available in place of 12M~. The CE-70 has internal terminations of all these impedances. Bridging measurements require the use of a Bridging Probe.

1.05 The CE-70 is equipped with a selectable 1.74kHz equivalent C-message bandwidth

filter with a switchable NOISE, or TONE, mode. This permits direct carrier or tone level-to-noise measurements on fully loaded systems. This filter also permits noise measurements directly in dBrnC or dBp. A narrow band, switch selected 75 Hz bandwidth filter for pilot or single frequency measurements is also included.

1.06 Calibration is rapidly and efficiently performed without disturbing the frequency

and level settings. When the CAL button is depressed all circuits are placed in the CAL mode at the frequency to which the CE-70 is tuned. It is then only necessary to set the meter to zero with the calibration control.

1.07 A Vernier Level control having a range of about 1. 5 dB is provided for ease of setting

o dB in making relative level measurements. An indicator light comes on to show that the control is out of the calibration position.

1.08 A BFO output provides a 0 dBm signal into 75n at the frequency to which the

CE-70 is tuned. This output is available at a BNC connector on the rear panel. A RECORDER Output, providing an 0.8 volt DC level for 0 dB reading on the meter, is also available on the rear panel through a BNC connecor.

1.09 A SIGNAL PRESENCE and an OVERLOAD light monitor the instrument input circuits.

The SIGNAL PRESENCE light indicates the presence of a signal that will cause the meter to read -8 dB or higher. The OVERLOAD light will come on whenever there is an interfering signal that will cause distortion in the first mixer circuit.

Page 2

COM CE-70

1.10 Audio demodulation of USB, LSB or AM is selected by front panel switches. Audio

output is available either through front panel phone jacks or an internally mounted speaker. For checking the quality of demodulated voice communications the optional 3.1 kHz BW should be used.

1.11 Provision is made on the front panel to supply power to an external bridging probe.

2. DESCRIPTION

OPERATING FEATURES

2.01 The front panel controls of the CE-70 Frequency Selective Levelmeter are shown

in Figure 2. A description of the operating Controls, Indicators and Connectors is given in Table A.

2.02 Rear panel connections are shown in Figure 3. A description of the rear panel

connectors is given in Table B.

16}---------- "'"\

PHYSICAL DESCRIPTION

2.03 The physical size of the CE-70 is: 7-3/4"H x 17-3/4" W x 22" D and the weight is

50 lbs. The instrument is powered from 115/230 VAC, 50-60 Hz and nominal AC input is 100 VA.

CHARACTE RISTICS

2.04 The characteristics of the CE-70 are given in Table C.

OPTIONS AND, ACCESSORIES

2.05 The CE-70 may be ordered with a 3.1 kHz bandwidth in addition to the standard 75 Hz

and 1.74 kHz bandwidths. An input impedance of 150n may be ordered in place of 124n. Two BNC to Coaxial adapters, PIN 2532-0001, are furnished with each instrument.

®------------.

HI)---+-_____

'-------------(10

'----------------{11

L--------------__--{Il

Figure 2. CE-70 Front Panel Controls, Connectors and Indicators

Page 35601"0062

COM CE-70

TABLE A

CE-70 FRONT PANEL CONTROLS, CONNECTORS AND INDICATORS

REF. NO. IFlG.2l

CONTROL. CONNECTOR OR INDICATOR FUNCTION

1 Frequency Display LED digital readout of frequency to which frequency dials are set.

2 MHz kHz Frequency dial selectors.

3 Level Display LED digital readout of attenuator setting.

4 Level Uncal Lights when Vernier dial not in CAL detent position.

5 Bandwidth Hz Switches select indicated IF bandwidth. (3.1 kHz bandwidth optional)

6 Search tl.F Manual tuning control for Search mode.

7 Search Decade Selects frequency increments for manual tuning.

8 Audio Monitor Dual or single jack output for headphone monitoring. Speaker automatically disconnected.

9 Audio USB/LSB/AM Selects type of demodulation.

10 Audio Volume Pwr Off Adjusts audio output volume. Power off switch in detent position.

11 Vernier Adjusts level between 1 dB steps.

12 1 dB/Step Adjusts one dB per step attenuator.

13 10 dB/Step Adjusts ten dB per step attenuator.

14 Tone/Noise Switches 20 dB attenuation between RF and IF for Tone or Noise measurement.

15 Input 600 600n balanced input, single tip ring sleeve jack W.E. 310.

16 Input 135 135n balanced input, dual tip sleeve jacks.

17 Probe Power +15V, banana jack connector.

18 Input 75 75n unbalanced input, coaxial jack.

19 Input 124 124Q balanced input, coaxial jacks.

20 Impedance Q Selects the required input impedance.

21 Norm/Exp Selects the Normal -20 dBm to +2 dBm or Expanded -1 dBm to +1 dBm meter scale. Resolution .05 dB.

22 Push to CAL Sets all circuits to the CAL mode.

23 Push to CAL Control Adjusts gain to calibrate meter.

24 Meter Indicates signal level referred to attenuator setting.

25 Input Overload Lights when input circuits overloaded.

26 Signal Presence Lights when input signal level is suitable for measurements.

Page 4 5601"0062

COM CE-70

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Figure 3. CE-70 Rear Panel Controls and Connectors

TABLE B

CE-70 REAR PANEL CONTROLS AND CONNECTORS

REF NO.

(FIG.31 CONTROL OR

INDICATOR FUNCTION

1 A (Black) A (Red) L.a. from CE-71 or CE-70.

2 E (Black) A (Red) L.a. to CE-71 or CE-70.

3 D (Black) 80 kHz to CE-71.

4 C (Black) C (Red) L.a. output to CE-71 or CE-72.

5 B (Black) 10 MHz output to CE-72.

6 Recorder Output 0.8V output for 0 dB on meter.

7 ON/OFF Switch to control BFa output.

8 BFa OUTPUT 0-25 MHz output at 0 dBm.

9 Cooling fan.

10 1-1/2A SB 115V 3/4A SB 230V

AC power fuse.

11 SWITCHED LINE OUTPUT Switch controlled AC power to CE-71 or CE-72.

12. 115V/230V AC power source voltage select switch.

Page 5 5601·'0062

COM CE-70

TABLE C

CE-70 SPECIFICATIONS

ITEM CHARACTERISTiC

FREQUENCY

Range

75.11 124.11 135.11 150.11 (Optional) 600.11

Accuracy

20° to 30° C 0° to 50" C Aging Error

Modes of Operation

Resolution

Fixed Tune Mode Search Mode

Display

1 kHz to 25 MHz 60 kHz to 11.5 MHz 10 kHz to 3.2 MHz 10 kHz to 5 MHz 1 kHz to 650 kHz

±20 HZ±l PPM ± 25 Hz ± 2 PPM < 5 PPM/year

Fixed tune

Search

±10 Hz 10 Hz, 100 Hz, 1000 Hz

7 digit red L.E.D.

LEVEL

Range (ref. to 0 dB on meter)

Display

Accuracy, After Level Calibration, 75.11 (Ref. to 0 dB on meter)

Tone Mode, 25°C ±5°C

75Hz Bandwidth

10 kHz to 18.6 MHz

-69 to +10 dBm -89 to -69 dBm

18.6 MHz to 25 MHz

-69 to +10 dBm -89 to -69 dBm

1 kHz to 10 kHz

-69 to +10 dBm -89 to -69 dBm

1.74 kHz Bandwidth, 3.1 kHz Bandwidth (Optional)

10 kHz to 25 MHz

-109 to +10 dBm

3 digit L.E.D.

±0.15 dB ±0.20 dB

±0.25 dB ±0.30 dB

±0.30 dB ±0.70 dB

±0.05 dB additional

Page 6 5601··0062

COM CE-70

TABLE C (Cont)


ITEM CHARACTERISTIC

I

,

Tone Mode, O°C to +55°C

Noise Mode, 25°C ±5°C

75 Hz Bandwidth

100 kHz to 18.6 MHz

-99 to -10 dBm -109 to -99 dBm

18.6 MHz to 25 MHz

-99 to -10 dBm -109 to -99 dBm

10 kHz to 100 kHz

-99 to -10 dBm -109 to -99 dBm

1.74 kHz Bandwidth, 3.1 kHz Bandwidth (Optional)

10 kHz to 25 MHz

Noise Mode, O°C to +55°C

Accuracy; 124, 135, 600n

25°C ±5°C O°C to +55°C

Accuracy: 150n (Optional)

.25°C to ±5°C O°C to +55°C

Digital Resolution

Analog Meter

Normal Mode Expand Mode Resolution Linearity Error

Expand. +1 dB to -1 dB

Normal Mode

+2 to -10 dB -10 to -15 dB -15 to -20 dB

Calibrate - Push to CAL button


±0.25 dB ±0.35 dB

±0.30 dB ±0.50 dB

±0.40 dB ±0.9 dB



±0.10 dB additional to 75n ±0.15 dB additional to 75n

±0.15 dB additional to 75n ±0.20 dB additional to 75n

1 dB and 10 dB steps plus vernier

-20 dB to +2 dB -1 dB to +1 dB

0.05 dB

±0.02 dB

±0.1 dB ±0.5 dB ±0.7 dB

CAL adjust automatically calibrates at selected frequency. Calibrate level: -40 dBm

Page 7

COM CE-70

TABLE C (Cont)


ITEM

INPUT

Impedance

Unbalanced Balanced

Standard Unit Optional Unit

Return Loss, 75D.

Tone Mode

-79 to +10 dBm -89 to -79 dBm

Noise Mode

-89 to -10 dBm -99 to -89 dBm

Return Loss, 124, 135, 600, 150D. (Optional)

Tone Mode

-79 to +10 dBm

-89 to -79 dBm

Noise Mode

-89 to -10 dBm

-99 to -89 dBm

Common Mode Rejection: 124,135,600, 150D. (Optional)

Input Protection

Overload Indicator (Display for 1800 channel noise input)

Tone Mode Noise Mode

Signal Presence Indicator

CHARACTERISTIC

Push button selectable

75D.

124D., 135D., 600D. 13 5D., 150D., 600D.

;;;. 30 dB ;;;. 20 dB

;;;. 30 dB ;;;. 20 dB

;;;. 30 dB, except for 1st octave of frequency range

;;;. 27 dB, including 1st octave of frequency range

;;;. 20 dB

;;;. 30 dB, except for 1st octave of frequency range

;;;. 27 dB, including 1st octave of frequency range

;;;. 20 dB

30 dB nominal

±60V DC, 1 ms transient

25 dB per channel overdrive, typical 45 dB per channel overdrive, typical

Displays for> -8 dB on meter.

Page B 5601··0062

COM CE-70

TABLE C (Cont)


ITEM

BANDWIDTH

75 Hz

3 dB 60 dB

1.74 kHz (Equivalent Noise Bandwidth)

3 dB 60 dB

3.1 kHz (Optional)

3 dB 60 dB

INTERNAL DISTORTION, NOISE MODE (10 kHz to 25 MHz)

Harmonic

For 60 dB Sensitivity Increase

Noise Power Ratio

Equivalent 1800 Channel System with Stop Band Slot at 8.002 MHz or 2.438 MHz, for 40 dB Sensitivity Increase

Equivalent 600 Channel System with Stop Band Slot at 2.438 MHz, for 40 dB Sensitivity Increase

INTERMEDIATE FREQUENCIES

IF 1 IF 2 IF 3

IF REJECTION

1 kHz to 100 kHz 1 kHz to 25 MHz

IMAGE REJECTION

AUDIO OUTPUT

Demodulation

Monitor Output

Level

CHARACTERISTIC

75 Hz ±10% < 350 Hz

2.3 kHz ±10% < 4.6 kHz

3.1 kHz ±10% < 6.2 kHz

> 75 dB below fundamental

54 dB minimum, 56 dB typical

56 dB minimum, 58 dB typical

50.7 MHz 10.7 MHz 80 kHz

> 70 dB > 80 dB

> 80 dB

AM USB, LSB (Offset by 2.0 kHz from IF)

odBm nominal into 600ft for 0 dB on meter

5601--0062 Page 9

I

COM CE-70

TABLE C (Cont)


ITEM

Residual Phase Jitter (CE-70 Tuned from 100 kHz to 25 MHz)

Tone Mode, for signals> -69 dBm, 20 Hz to 300 Hz away from carrier, for 5 dB overdrive on meter

Harmonic Distortion, 1 kHz tone

Speaker Output variable

RECORDER OUTPUT

Level

Connector (Rear panel)

BFO OUTPUT

Level

10 kHz to 25 MHz 1 kHz to 10 kHz

Connector (Rear panel)

TIME BASE OUTPUT (Rear Connector BB)

Frequency

Level

Connector

FIRST LOCAL OSCILLATOR CIRCUITS (Rear Connectors AA and CC)

Frequency

Level

Connector

THIRD IF OUTPUT (Rear Connector D)

Frequency

Level

Connector

PROBE POWER (Front Panel)

POWER REQUIREMENTS

0.5 0 P-P nominal

5% maximum

100 mw maximum

CHARACTERISTICS

0.8 volts DC, typical into 1Kn for 0 dB on meter

BNC

odBm ±0.2 dB into 75n odBm ±0.25 dB into 75n

BNC

10.000000 MHz

-10 dBm ±4 dB into 50n

BNC

50.7 to 75.7 MHz


BNC

80 kHz


BNC

+15V DC, 50mA maximum

115V ±10% (230V ±10% optional) 50 to 60 Hz, 100 VA nominal

Page 10 S601··0062

COM CE-70

TABLE C (Cant)


ITEM CHARACTERISTIC

DIMENSIONS

WEIGHT

ENVIRONMENTAL

Temperature Range

Operating Storage

7-3/4" H x 17-3/4" W x 22" D

50lbs.

O°C to +55°C -40°C to +75°C

3. PREPARATION FOR USE

UNPACKING AND INSPECTION

3.01 When unpacking the CE-70 Frequency Selective Levelmeter, inspect the packing

box and instrument for signs of possible damage. Verify satisfactory performance as outlined in the operating instructions (Section 5) of this manual. If the instrument is damaged, fails to operate properly or if any of the accessories are missing, file a 'claim with the transportation agency, or, if insured separately, with the insurance company.

POWER REQUIREMENTS

3.02 The CE-70 operates from a 115 or 230 volt (±10%) AC source, 50 to 400 Hz with a

nominal 100VA input. A 1-1/2A SB (3/4A SB for 230 VAC) fuse provides protection.

GROUNDING REQUI REMENTS

3.03 The CE-70 is equipped with a three-conductor power cable which, when plugged

into an appropriate receptacle, grounds the instrument. To preserve this protection when operating the instrument from a two-wire outlet, use a threeprong to two prong adapter and connect the green lead on the adapter to ground.

WARM-UP REQUIREMENTS

3.04 There are no special warm-up requirements for the CE-70. The instrument is ready for

use as soon as it is turned on. Operational Calibration should be performed periodically, however, for the first sixty minutes of use.

5601"0062

4. CALIBRATION

4.01 In the Calibrate mode the instrument is automatically set up and the calibration

signal supplied. The calibration signal is the same frequency to which the instrument is tuned. For calibration the Level is automatically set to -40 dBm, the instrument placed in the TONE mode and the VERNIER disengaged.

4.02 Calibrate the CE-70 as follows:

(a) Ensure that rear panel BNC connectors EA and AA are interconnected by a short cable.

(b) Depress the PUSH TO CAL and the METER EXP switches.

(c) Set the BANDWIDTH to 75 Hz.

(d) Tune the CE-70 to the frequency to be measured.

Note: It is advisable to disconnect the instrument from the FDM carrier system during calibration in order to obtain the highest precision.

(e) Adjust the meter to 0 dB on the Expanded (lower) scale, using the control to the right

of the PUSH TO CAL switch.

(f) Depress the Meter NORM switch. The meter should read 0 dB ±O.l dB on the upper scale.

(g) Depress and release the PUSH TO CAL switch. The CE-70 is now ready for making

measurements.

Page 11

COM CE-70

5. MEASUREMENTS

COMMON PROCEDURES

5.01 Set the CE-70 controls as follows:

(a) Select the proper input impedance by depressing the switch having the appro

priate label. Connect the system to the jacks with a suitable cable. The 75.12 line is an unbalanced input while the 124.12, 135.12, 600.12 (150.12 optional) are balanced inputs.

Note: Although separate inputs are provided for each impedance, only one system should be connected to the CE-70 at any one time. This will avoid errors in the measurement due to crosstalk.

(b) Set the LEVEL controls for the expected signal levels using both the 10 dB/step and

the 1dB/step controls. The LEVEL readout shows the level for 0 dB on the meter. The actual level is the algebraic sum of the Level readout and the meter reading. The Level may be set over the range of +10 dBm to -89 dBm in the TONE mode and from -10 dBm to -109 dBm in the NOISE mode.

(c) Set the FREQUENCY selector controls to the desired frequency.

(d) Set the BANDWIDTH switch to 1.74 kHz. The signal should appear on the meter. If

not, set the SEARCH/DECADE switch to either 1 kHz, 100 Hz or 10 Hz. Rotate the 6 F Control to search for the signal. As the CE-70 is tuned through the signal the SIGNAL PRESENCE light will come on momentarily. Adjust 6 F until the light stays on and note the Frequency of the readout. Switch the SEARCH/DECADE Control to OFF and set the Frequency controls to the Frequency noted. The signal will now appear on the meter.

Note: If the INPUT OVERLOAD light comes on it indicates that there is in the input a signal 25 dB higher (in the TONE mode; 45 dB higher in the Noise mode) than the signal being measured, and that the input circuits of the CE-70 are being overloaded. Inaccurate measurements could result because the CE-70 is not being operated in its specification region. If the INPUT OVERLOAD light comes on in the TONE mode, switch to the NOISE mode. If the light comes on in the NOISE mode a bandpass, low pass or high pass filter in the input of the CE-70 is required.

Page 12

5.02 Relative dB measurements are easily made by using the VERNIER LEVEL control.

The Level is adjusted to the 0 dB mark on the meter at the Frequency of interest by adjusting the VERNIER control. The difference in dB is then readily found for bandwidth measurements or for the comparison of other signals by tuning to the frequencies of interest and reading the difference on the meter. The LEVEL UNCAL light remains on whenever the VERNIER is out of its calibrated position to indicate this fact.

5.03 Noise measurements, using the 1.74 kHz bandwidth, are easily made by using the

relationships .of dBrnC == .CE-70 reading in dBm +90.5 dB and dBp == CE-70 reading in dBm + 90.0 dB. This is based on the CE-70 measured dBm reading related to C message equivalent or psophometric equivalent weighted noise as follows:

dBrnC or dBp =CE-70 dBm + 90 dB + BWfdB + MfdB

BWf == Bandwidth factor

Cmsg == -0.35 dB p = -1.2 dB

Mf = Meter factor

CE-70 average reading rectifier meter calibrated for RMS = +1.05 dB

dBrnC == CE-70 dBm +90 dB -0.35 dB +1.05 dB ~ CE-70 dBm +90.5 dB

dBp = CE-70 dBm +90 dB -1.2 dB +1.05 dB ~ CE-70 dBm +90 dB

FREQUENCY RESPONSE MEASUREMENT USING BFO OUTPUT

5.04 Proceed as follows:

(a) Calibrate the CE-70 and perform the Common procedures of paragraphs 4.02

and 5.01.

(b) Connect to the system under test as shown below:

SYSTEM

UNDER TEST OUTPUT 7Sfl

ATTENUATOR

5601"0062

COM CE-70

OPERATING NOrES

The following general operating principles should be kept in mind so that most effective use may be made of the CE-70 FSIM.

(a) When making tone level measurements the CE-70 should always be set to the

TONE mode and to 75 Hz BANDWIDTH. Tone measurements may be made down to -89 dBm.

(b) For precision tone measurements the CE-70 should always be calibrated in the

75 Hz BANDWIDTH. If tone measurements must be made in the 1.74 kHz or 3.1 kHz BANDWIDTH, the tone should first be tuned in using the 75Hz BANDWIDTH. Then the tone signal should be disconnected and the CE-70 set to the wider BANDWIDTH and then calibrated without altering the Frequency setting. The signal is then reconnected and the measurement made.

(c) When making noise level measurements the CE-70 should always be placed in

the NOISE mode and the BANDWIDTH set to 1.74 kHz.

(d) The CE-70 should not be operated below 10 kHz unless in the 75 Hz BANDWIDTH

mode to prevent noise and L.a. feedthrough from degrading the measurements.

(e) If the instrumen t is operated below 3 kHz in any BANDWmTH mode, the Band

width filters may take a 0.1-0.3 dB set. After again tuning above 3 kHz this set will die out gradually in about 15 minutes. If the instrument is to be used above 3 kHz immediately afterwards, it should be calibrated before every measurement for about 15 minutes, until the set has disappeared.

(f) When voice quality is to be checked the 3.1 kHz BANDWIDTH should be used.

(g) To avoid any errors due to crosstalk, only one system at a time should be

connected to the CE-70.

(h) When making Frequency Response measurements using the BFa output the level

should not be adjusted lower than -69 dBrn, and frequency should stay above 10 kHz.

(i) Remember that dBrnC = CE-70 dBm +90.5 dB, and dBp = CE-70 dBm +90 dB.

(c) Set the BFa switch on the rear panel to ON. The output level is 0 dBm. Adjust

the level to the system under test with an external attenuataI'.

(d) Set SEARCH control to OFF. Set the Frequency to the reference frequency to

be used in the test using the Frequency selector digital dial controls.

(e) Set the CE-70 to the TONE mode. Set the LEVEL controls for an indicated level of

o dB on the meter, using the Expanded scale. The absolute level should be -69 dBm or higher, and the frequency should be 10 kHz or higher.

(f) Adjust the VERNIER control for an exact o dB reading on the meter. In this manner

the frequency response may be obtained relative to the reference frequency specified.

(g) Set the SEARCH DECADE control to either 1 kHz, 100 Hz or 10 Hz. Rotate the t:J. F

Control to tune over the desired frequency range. The Frequency readout and the BFa output will

5601"0062

advance in steps according to the DECADE Control setting. The rate at which the frequency is changed is directly proportional to the rate at which the t:J.F Control is rotated.

(h) The frequency response down to the 20 dB points can be measured directly on the

meter. Lower levels may be reached by adjusting the 10 dB/step and 1 dB/step attenuataI'.

CautiO/I: Do not make frequency response measurements using the BFO output at a level

lower than -69 dBm at meter zero or lower than 10kHz, to prevent BFO crosstalk.

SINGLE FREQUENCY (PILOTS, CARRIER LEAK AND TEST TONES)


(a) Calibrate and perform the common procedures as given in paragraphs 4.02 and 5.01.

(b) Set the Frequency controls to the frequency of the signal to be measured. Set th e BAND

WIDTH to 75 Hz.

Page 13

I

COM CE-70

(c) Set the SEARCH DECADE control to 10 Hz. Tum the t. F Control for a maxim um indi

cation on the meter.

(d) Increase the sensitivity to bring the signal peak toward the 0 dB region of the meter

scale. Depress the EXP Control for ±1 dB full scale reading on the meter for greater resolution. (If a slight beat is noticed on the meter needle, detune the frequency by 10 Hz.) The level in dBm is the algebraic sum of the LEVEL display and the meter reading. This is true for all impedance .modes.

(e) Before taking the reading make certain that the LEVEL UNCAL light is out, and the

SIGNAL PRESENCE and EXP lights are on. For precision measurements the TONE mode should always be used.

Note: If TONE measurements must be made using 1.74 kHz or 3,1 kHz BW, first peak the signal in the 75Hz BW mode, disconnect signal from input, switch to desired BW, CAL the CE-70 and then reconnect the signal to the input to make the measurement. This procedure gives the highest accuracy.

SINGLE FREQUENCY IN dBmO

5.06 The term dBmO is widely used in Microwave and Carrier systems to express noise and

signal power in terms of the levels that should exist at zero transmission level points (OTLP). The power level at any transmission level point can be expressed in dBmO by adjusting the measured power by the difference in level between the measured power and the reference level at that transmission level point.

(a) For example: A tone level of -40 dBm measured at a -16 dB transmission level

point is equivalent to -24 dBmO.

(b) A tone level of +17 dBmO is equivalent to +7 dBm measured at a -10 dB transmission

level point.

SPURIOUS TONES IN TERMS OF dBrn AND dBrnO


(a) Since any spurious tones or noise superimposed on a conversation have an inter

fering effect, it is desirable to have all interfering

Page 14

effects expressed in positive numbers. A 1000 Hz tone at -90 dBm was selected as a reference power having negligible interfering effect. Any interfering effect above the reference level of -90 dBm at 1000 Hz is defined in units of dBm.

(b) To convert a spurious signal level from dBm to dBm add 90 dB to the dBm level.

(c) To convert dBm to dBmO subtract the transmission level point (TLP) level from

the dBm number. For example: A +40 dBm level at a -10 dB transmission level point is equivalent to +50 dBmO (+40 dBm - (-10 dB) = +50 dBmO).

TONE LEVEL ON SSB CHANNELS


(a) Calibrate and make control settings as given in paragraphs 4.02 and 5.01.

(b) Tune the CE-70 to the center of the channel. (Carrier frequency plus 2 kHz for USB, or,

minus 2 kHz for LSB.)

(c) The audio signals will be present at the MONITOR output jacks and the channel

may be monitored for noise and interference. Adjust the volume control for audible signals on the speaker.

(d) To measure the amplitude of any tone set the CE-70 BANDWIDTH to 75Hz and tune

for maximum indication on the meter. Adjust the signal to about the 0 dB level on the meter using the step attenuator controls. The level will be the algebraic sum of the LEVEL display and the meter reading.

FLUCTUATION NOISE IN dBp, dBrnC, dBrnCO


(a) Calibrate and make control settings as given in paragraphs 4.02 and 5.01.

(b) Tune the CE-70 to the center of the channel.

(c) Set the TONE/NOISE switch to NOISE and set BANDWIDTH to 1. 74kHz.

(d) Increase the sensitivity wi th the step attenuator controls for an on scale reading on

the meter. If the meter suddenly "pegs" with a

5601··0062

small increase in sensitivity the mixer is being overloaded by the adjacent channel. In this case the INPUT OVERLOAD light will come on to indicate that the input mixer is overloaded. When this is the case a high pass, low pass, or bandpass filter is required between the system being tested and the CE-70 input.

(e) The channel noise level in dBm is the algebraic sum of the LEVEL display and

the meter reading.

(f) The dBp (psophometric weighted) noise reading is equal to the CE-70 reading in

dBm plus 90 dB.

(g) The dBrnC (C-message weighted) noise reading is the CE-70 reading in dBm plus

90.5 dB.

(h) The dBrnCO noise reading is equal to the noise reading in dBrnC minus the TLP

level. For example: A noise level of 40 dBrnC at a -10 dB TLP is equal to +50 dBrnCO (+40 dBrnC - (-10 dB) ::= +50 dBrnCO).

SPURIOUS SIGNALS


(a) Determine the lower frequency at which the search is to begin. Tune the CE-70 to this

frequency with the SEARCH/DECADE Control in the OFF position.

(b) Set the SEARCH/DECADE Control to 1 kHz and set BANDWIDTH to 1.74 kHz.

(c) Set the LEVEL Controls to the specified level limits for spurious tones.

(d) Search for spurious signals by rotating the flF Control in a clockwise direction. This

steps the CE-70 up in 1 kHz steps. The SIGNAL PRESENCE light will come on as the frequency is tuned through spurious tones greater than -8 dB on the meter.

(e) To make an absolute level measurement, place the SEARCH/DECADE switch in the

10 Hz position and set BANDWIDTH to 75 Hz. Tune for a maximum reading on the meter. The spurious tone level is the algebraic sum of the LEVEL display reading and the reading on the meter.

5601··0062

COM CE-70

NOISE POWER RATIO (NPR)


(a) Connect the CE-70 to the baseband output at the receive side of the FDM system (the

entrance link for coaxial cable; the output of the FMR receiver discriminator for microwave radios).

(b) Load the FlDM system with the full load white noise specified for that system, at

the baseband input On the Transmit side of the Coax Cable system (baseband input of the FMT for microwave radios).

(c) Calibrate the CE-70 and perform COmmon procedures as given in paragraphs 4.02

and 5.01.

(d) Place the CE-70 in the NOISE mode and set BANDWIDTH to 1.74 kHz.

(e) Tune to the center of the channel in which, the NPR is to be measured.

(f) Measure the noise level in this channel (algebraic sum of LEVEL display and meter

reading). Note level in dEmo

(g) Slot out the noise in this channel at the transmitter end of the FDM system.

(h) Again measure the residual noise at the receiver end of this channel.

(i) The NPR is the difference in the readings of (f) and (h). If step ,(f) reading is -40 dBm

and step (h) is -80 dBm the NPR is 40 dB (-40 dBm -,(-80 dBm) "" 40 dB).

PHASE JITTER


(a) Calibrate the CE-70 and perform cornman procedures as given in paragraphs 4.02

and 5.01.

(b) Set controls to TONE mode, 1.74 kHz BANDWIDTH and LSB.

(c) Connect a Phase Jitter Meter to either one of the MONITOR jacks on the CE-70 front

panel. (A Bradley 75LS Phase Jitter Meter or equivalent is suggested.)

Page 15

COM CE-70

(d) Tune to the carrier or reference frequency minus 1.00 kHz in the FDM system being

tested. For example: if the phase jitter on the group pilot, 104.08 kHz, is being measured, tune the CE-70 to 103.08 kHz. This will provide a frequency translated tone of 1 kHz at the MONITOR output jacks.

(e) Adjust the LEVEL controls for a level +5 dB higher than the 0 dB level of the meter.

(f) Adjust the VOLUME control for the proper level into the phase jitter meter.

(g) Measure phase jitter directly with the Phase Jitter Meter.

No te.' Phase jitter can be further reduced by adjusting the LEVEL con troIs for a level greater than +5 dB but not more than +20 dB higher than the 0 dB level of the meter. This will cause the meter to peg high which is acceptable as meter is protected.

BRIDGING PROBE


(a) Set the CE-70 to 75.12. Insert the Probe connector into the 75.12 INPUT jack making

certain that the banana plug properly enters the PROBE PWR connector.

(b) Perform the calibration and common procedures of paragraphs 4.02 and 5.01.

(c) Connect the Probe to the system and perform measurement according to the fore

going procedures.

REPAI R SERVICE

5.14 In the event that repair is required, contact:

Cushman Electronics, Inc. Customer Service Department 2450 North First Street San Jose, California 95131 Telephone: (408) 263-8100

5.15 Cushman Electronics repair service is also available at the following service centers:

Page 16 16 Pages

Cushman Eastern Service Facility 100 Parish Drive Wayne, New Jersey 07470 Telephone: (201) 696-0545

B.C.S. Associates, Inc. 940 North Fern Creek Avenue Orlando, Florida 32803 Telephone: (305) 896-4881

Reshal Associates, Inc. 219 West University Drive Arlington Heights, Illinois 60004 Telephone: (312) 398-7660

PREPARATION FOR RESHIPMENT

5.16 It is recommended that the shipping box and foam packaging be kept in case it

becomes necessary to return the instrument to the factory or the service center for service or repair.

5.17 The following 'paragraphs contain a general guide for repackaging of the instrument for

shipment.

(a) Attach a tag to the instrument identifying the owner, and indicate the service or repair

to be made. Include the model number and full serial number of the instrument. In any correspondence, identify the instrument by model and serial number.

(b) Place the instrument in the original container. Make certain that the container is

well sealed with strong tape.

(c) If the original container is not used, wrap the instrument in plastic or heavy paper

before placing in an inner container.

(d) Place packing material around all sides of the instrument.

(e) Place the instrument and inner container in a heavy carton and seal with strong tape.

(f) Mark the shipping container: "DELICATE ELECTRONIC INSTRUMENT", "FRAGILE".

5601"0062.

Dear Customer:

Every effort is made at Cushman to deliver a better product.

If a correction or improvement should be made in this manual, please indicate it on one of the postpaid cards attached and drop it in the maHo

Help us to help you.

Cushman Electronics, Inc. Publications Department

Operations Cushman Maintenance Manual, Model!CE- _

Instruction

I would like to see the following corrections/improvements made in this manual:, _

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5599-0002

I II II I NO POSTAGE NECESSARY IF MAILED

IN THE UNITED STATES

BUSINESS REPLY MAIL FIRST CLASS PERMIT NO. 6411 SAN JOSE, CA

POSTAGE WILL BE PAID BY ADDRESSEE

Cushman Electronics, Inc.

2450 North First Street San Jose, CA 95131

ATTN: PUBLICATIONS DEPT.

I II II I NO POSTAGE NECESSARY IF MAILED

IN THE UNITED STATES

BUSINESS REPLY MAIL FIRST CLASS PERMIT NO. 6411 SAN JOSE, CA

POSTAGE WILL BE PAID BY ADDRESSEE

Cushman Electronics, Inc.

2450 North First Street San Jose, CA 95131

ATTN: PUBLICATIONS DEPT.

cushman electronics ce-70 frequency selective levelmeter ~ operation manual, 07-1976

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