UNIVERSITY OF HONG KONGLIBRARY

This book was receivedin accordance with the Books

Registration OrdinanceSection 4

CONSULTANCY STUDY ON

ORDINANCE

•-'•'-883605.,

November 1987

Prepared by Danish Research Centre forApplied Electronics, ElektronikCentralen

for Industry Development Board

TABLE OF CONTENTS PAGE

1. INTRODUCTION 1

2. RFI REQUIREMENTS OF HONG KONG's MAJOR 2EXPORT COUNTRIES

2.1 International and National organizations 2dealing with RFI

2.1,1 Diagram of the standardization work 42.2 Approval procedures 52.3 Classification of product categories 62.4 Description of RFI requirements by product 7

category2.4.1 Standards for household appliances 72.4.2 Standards for radio and television receivers 152.4.3 Standards for walkie-talkie and similar 19

transmitters2.4.4 Standards for computing devices 212.5 Future development trends 34

3. INSTRUMENTATION AND FACILITIES 363.1 Instrumentation 363.1.1 Conducted emission 363.1.2 Radiated emission 413.1.3 Radiated power 423.1.4 Susceptibility test 423.1.5 Peripherals 423.2 Facilities 423.3 Suppliers and economic considerations 453.3.1 Facilities 453.3.2 EMI meters 463.3.3 Accessories 473.3.4 Software and peripherals 483.3.5 Complete automatically operated test systems 483.4 Calibration and maintenance 483.5 Need for recognition of test results 493.5.1 Accreditation schemes 523.5.2 International standardization organizations 53

LIST OF APPENDICES

APPENDIX 1 : Definitions of terms 54APPENDIX 2 : Addresses of foreign 68

teleadministrations

PAGE

LIST OF FIGURES

FIG. 1 RFI measurements on household 8appliances

FIG. 2 Examples of discontinuous 9interference classified as clicks

FIG. 3 Examples of discontinuous 10interference for which the limitsof continous interference apply

FIG. 4 RFI measurements on radio and 16television sets

FIG. 5 Measurements on walkie-talkies 20

FIG. 6 RFI measurements on ITE 22

FIG. 7 Impedance characteristic for a 3750 H mains network

FIG. 8 Impedance characteristic for a 385 ji H mains network

FIG, 9 Conversion between a 5 H and a 3950 M-H mains network

FIG. 10 The organizational structure of 53the IEC

1. I1TRODUCTION

(1) Many electronic and electrical products manufactured in Hong Kongfor export have to comply with stringent and mandatory overseasradio frequency interference (RFI) requirements. Localmanufacturers have experienced difficulties in complying withthese requirements. This has, to some extent5 impeded the growthand diversification of the electronics and electrical industries.

(2) Against this background, the Danish Research Centre for AppliedElectronics (ElektronikCentralen) was commissioned in October1985 to carry out a study of RFI requirements.

(3) The study was completed in November 1987. This publicationcontains extracts from the report covering two topics, the RFIrequirements of Hong Kong's major export markets and theinstrumentation and facilities for RFI testing.

2. RFI REQUIREMENTS OF HONG KOHG8S MAJOR EXP01T COUNTRIES

2.1 International and national organizations dealing with RFI

(4) Some of the most important international organizations dealingwith RFI are the

IECCISPRCENELEC

(5) But also many national organizations are important because -despite of their national status - the standards are often usedin trade agreements in other countries. Below, the abbreviationsfor the RFI organizations are indicated.

(6) IEC (International Electrotechnical Commission) is coveringalmost every aspect of electrical standardization. Recommendedmethods of measurements of interference from various apparatusare given. The legislation work is done by national authorities.In many countries the Post Office carries out the control whetherthe products conform to the national regulations.

(7) CISPR (Comite International Special des Perturbations Radioelec-triques) is a special committee under the IEC, dealing with radiointerference. The object of CISPR is to promote internationalagreement on measures against radio interference from specificsources (products), thereby facilitating international trade.Until now the following interference sources are covered by CISPRpublications:

Information technology equipment

Electrical appliances of all types

Ignition systems (for instance in automobiles)

Electricity supply systems, including electrictransport systems

Industrial, scientific and electro-medical radiofrequency equipment (ISM apparatus)

Sound and television broadcasting receivers

(8) CEN1LKC (Comite Euorpeen de Normalisation Electrotechnique) hasthe object to harmonize the national electrotechnical standardsof the member countries (all West European countries) and to re-move trade barriers which may result - directly or indirectly -from the operation of national marks.

(9) EEC (European Economic Community) prepares directives on thebasis of documents published by CENELEC. The EEC directives aremandatory in all member countries.

(10) CEFT (Conference Europeen des Administrations des Postes et desTelecommunications) is an European organization publishing recom-mendations for walkie-talkies, intercom systems, cordless tele-phones, etc. The national Post Offices have their own regula-tions, which are more or less in accordance with the CEPT regula-tions.

(11) The international reputation of some national organizations hasmade their standards well known, and they are often referred toin RFI matters. Among these organizations are:

Federal Communications Commission (FCC)Fernmelde-Technisches Zentralamt (FTZ)Verband Deutscher Elektrotechniker (VDE)British Standard (BS)Zentralamt fur Zulassungen im Fernmeldewesen (ZZF)

(12) FCC (Federal Communications Commission) is an American federalorganization publishing Rules and Regulations for RFI. Accordingto public law No. 90-379, which amends the Communications Act of1934, the FCC has the authority to prescribe regulations for themanufacturers, the import, the sale, the shipment, or the use ofdevices, which can cause harmful interference to radio reception.The published Rules and Regulations are divided into severalparts. The most important parts for the Hong Kong industries are:

Part 2 (General Rules and Regulations)

Among other things, a description of how to obtaincertification is given.

Part 15 (Radio Frequecy Devices)

Here Subpart J gives special attention to computingdevices, which are sources of RF energy radiation.

Part 18 (ISM Equipment, e.g. microwave ovens)

Part 95 (Personal Radio Services)

(13) BS (British Standard publishes national standards for the UK.Relevant standards for the Hong Kong industries are BS 800, BS905 and BS 6527. These standards are based on the internationalwork inside IEC and CISPR, The limits and methods of measurementare almost completely in agreement with recommendations of theseorganizations.

(14) FTZ (Fernmelde-Technisches Zentralamt) is a section of the GermanPost Office. It can be compared with the FCC in the USA* Measuringmethods and rules and regulations for various types of equipmentare prepared by FTZ. For certain equipment categories type appro-val tests can be obtained at FTZ's laboratories. For other equip-ment categories FTZ has given VDE mandate as the only laboratory

to carry out the prescribed tests. The rules and regulations setup by FTZ are published as "Norms". Some of these norms are putinto force by law. They are put into force by "Verfiigungen"(Vfg.) No. 1044, No. 1045 and No. 1046 concern household applian-ces (1045) and computers (1046).

(15) ¥DE "Verband Deutscher Elektrotechniker" (Association of GermanElectrical Engineers) is comparable with UL in the USA, and ex-tended with RFI facilities, thus both safety and electrical emis-sion can be tested. VDE is an independent non-government institu-tion. Specifications are published as VDE norms. They are to beregarded as test standards, and they are not mandatory until theyare put into force by law by the Post Office. The announcement ofthis is published in "Verfiigungen11.

(16) Many of the VDE norms have both a VDE number and a DIN number(Deutsche Industri Normen). Special attention shall be given toVDE 0875 (DIN 57875) and VDE 0871 (DIN 57871) which concernhousehold appliances and computers.

(17) 2ZF "Zentralamt fur Zulassungen im Fernmeldewesen11 is a govern-ment body which formerly was part of FTZ. ZZF takes care of allRFI approvals. Before the set up of ZZF the approvals were grant-ed by FTZ. The ZZF was built in order to separate the approvalauthorities from the legislation (FTZ).

2.1.1 Diagraa of the standardization work

(18) The above mentioned abbreviations constitute a mixture of natio-nal and international standardization organizations and nationalgovernment bodies which adopt existing standards into law and in-corporate these standards into their national legislation system.From a manufacturer's point of view it seems to be a large numberof standards to cope with, but the technical requirements for aspecific product, e.g. computers, are more or less identical inmost parts of the world. The differences ate found in the admi-nistrative way to obtain approvals, certifications, etc.

A flow chart of the standardization work is given below:

IEC/CISPR

CENELEC National standards e.g.

EEC National legislation e.g.

VDEFTZBSDIN

f FCCVerfiigung(based onVDE, FTZ,

I or others)

2.2

(19)

(20)

(21)

(22)

(23)

(24)

(25)

Approval procedures

The approval procedures in various countries are different anddepend on the type of product.

The FCC distinguishes between "Type Approval11, nType Acceptance" ,"Certification", and "Verification".

Approval is an equipment authorization issued by theCommission. It is based on examination and measurement of one ormore sample units by the Commission at its laboratory.

Type Acceptance is an equipment authorization issued by the Com-mission for equipment to be used pursuant to a station authoriza-tion. Type acceptance is based on representations and test datasubmitted by the applicant. Type acceptance is primarily used forbroadcasting systems.

Certification is an equipment authorization issued by the Com-mission for equipment designed to be operated without individuallicense under Parts 15 and 18 of its rules. It is based on repre-sentations and test data submitted by the applicant.

Verification is a procedure where the manufacturer carries outmeasurements or takes the necessary steps to insure that theequipment complies with the appropriate technical standards. Sub-mittal of a sample unit or representative data to the Commissiondemonstrating compliance is not required unless specificallyrequested by the Commission.

The above mentioned methods for equipment authorization proce-dures are not optional for the manufacturers. The procedure to beused is specified in the rules covering the particular device.

(26) In Europe the authorities operate with concepts as "Approval",Registration11 and "Manufacturers Declaration".

(2?) Approvals normally require submittal of a sample to the nationalauthorities for test. When the sample has passed the test alicense number or a radio protection mark is issued and the pro-ducts can be marketed.

(28) Registrations are often based on measurements carried out by themanufacturers or independent test houses to prove that the legalrequirements are met. It is not necessary to submit any sample tothe national authorities. However, detailed information such aspower consumption, diagrams etc. is required by the authoritiesbefore the product can be marketed.

(29) Manufacturers declarations are used in the EEC community to statethat the mandatory requirements are met. It must be written inthe instruction manual or in the warranty card in all languagesof the member countries that the product complies with the stan-dard in question.

(30) More details about the approval procedures will be given underthe section about RFI requirements for different productcategories.

of product categories

(31) The products of Hong Kong Industries can be divided into groupsaccording to their interference sources.

Electrical household appliancesRadio and television receiversWalkie-talkies and similar transmittersComputing/information technology equipment

(32) RFI requirements are in force in Europe for electrical householdappliances using commutator motors with power consumptions ofless than 2 kW, thyristors and triacs for currents less than 16Aand appliances generating discontinuous interference originatingfrom contact functions such as thermostates or the electricalrelays in washing machines.

(33) Radio and television receivers have to meet RFI requirements dueto their local oscillator.

(34) Computing/ information technology equipment using high frequencysignals with a frequency above 9 kHz such as clock generators,switch mode power supplies etc. also have to comply with variousRFI requirements .

(35) Walkie-talkies and similar transmitters are limited in theradiated power on the allocated transmitting frequencies and

especially the radiated field strength outside the allocatedfrequency bands.

(56) The four product categories have been chosen, in the first place,because they represent a major part of the export from theHong Kong Industries, a fact, which certainly could be supportedby statistic figures. Secondly, the general disposition of theauthorities is to set up rules and regulations for equipment,which is produced in great numbers and spread out to a largenumber of consumers. The major part of the existing RFI require-ments all over the world are addressed to these products.

2.4 Description of RFI requirements by product category

2.4.1 Standards for household appliances

(37) Many household appliances are incidentally radiating devices dueto commutator motors (hair dryers, tools etc.), thyristors ortriacs (speed control units, heating regulators, etc.), relays,etc. Measuring methods and limits have been set up in order tocontrol the radio frequency interference from such devices. Theinternational standard is:

CISPR Publication 14, second edition 1985

Limits and methods of measurement of radio interferencecharacteristics of household electrical appliances, port-able tools and similar electrical apparatus.

(38) CSA C108.54 and the EEC Directive 82/499/EEC have been broughtinto line with this CISPR Publication.

(39) As all EEC countries are bound to adopt the EEC Directives, thelatest editions of VDE 0875 (Teil 1) and BS 800 are a directtranslation/copy of the mentioned directive.

(40) No legal requirements for household appliances are in force inthe USA.

2.4.1.1 Measuring method

(41) Interference measurements on household appliances involves2 main procedures:

Inteference voltage on mains leads 1 / f T *Inteference power on mains leads JInteferepce power

(42) Before going through the measuring methods, some definitions mightbe useful.

HOUSEHOLD APPLIANCES

MAINS PLUG MAINS W I R E

INTERFERENCE VOLTAGE (dBjiV)

0.15 - 30MHz

RADIATED POWER IdBpW)

30 - 300MHz

ELEKTRQNIKCEHTRALEN-

FIG. 1 RFI measurements on household appliances.

Continuous interference

(43) Electromagnetic disturbance, the effect of which is not resolv-able into a succession of discrete impulses in the normal oper-ation of the particular receiving system concerned.

(44) Commutator motors as well as other devices incorporated in house-hold appliances, portable tools and similar electrical apparatusmay cause continuous interference.

Discontinuous interference (see FIG. 2 and 3)

(45) Switching operations in thermostatically controlled appliances,automatic programme controlled machines and other electricallycontrolled or operated appliances generate discontinuous inter-ference. The subjective effect of discontinuous interferencevaries with repetition rate and amplitude in the case of bothsound radio and television. For that purpose, distinction is madebetween various kinds of discontinuous interference. The samemeasuring equipment is used as specified for continuous inter-ference. If the interference can be classified as discontinuousa relaxation of the limit can be given.

- < 200 ms

One clickDisturbance not longer than 200 ms, consisting of a continuous series of impulses and observed at the intermediatefrequency output of the measuring receiver.

- < 200 ms -

One clickInd iv idua l impulses shorter than 200 ms, spaced closer t han 200 ms, not cont inuing for more than 200 ms and observed atthe intermediate frequency output of the measuring receiver.

< 200 ms -

Two clicks

Two disturbances nei ther exceeding 200 ms, spaced by a min imum of 200 ms and observed at the intermediate frequencyoutput of the measuring receiver.

FIG. 2 Examples of discontinuous interference classified ascliks.

-< 200 ms-

Uv/ijUj iidWi!"V i*y^/uv i i

iwnr - » 200 ms -L/VrYT'

- > 200 ms -

f 1'- < 2 $ -

More than two clicks in a period of 2 s and observed at the intermediate frequency output of the measuring receiver.

-200ms-

-> 200 ms-

I ndividuai impulses shorter than 200 ms. spaced closer than 200 ms, continuing for more than 200 ms and observed at theintermediate frequency output of the measuring receiver.

10

-< 200 ms-***—< 200ms-^+*- <200m$-»J

reauencv o u f h •requency output of the measuring receiver. ° ms *nd observ

FIG. 3 Examples of discontinuous interference for which thelimits of continuous interference apply.

11

(46) The frequency range where the RFI has to be controlled is 0.15-300 MHz. This is divided into two ranges:

0.15 - 30 MHz conducted emission30 - 300 MHz radiated power

(47) The measuring equipment shall comply with CISPR Publication 16.The standard prescribes measurements of RFI voltages, using anartificial mains network in the frequency range 0.15 - 30 MHz.The impedance of this shall be 50 J2/50 yH.

Disposition of appliances their connection to the artificialmains network

(48) The appliances shall be placed 40 cm above an earthed conductingsurface of at least 2 m square and shall be kept at least 80 cmfrom any other earthed conducting surface. If the measurement ismade in a screened enclosure, the distance of 40 cm may bereferred to one of the walls of the enclosure.

(49) If the appliance is supplied without a flexible lead, it shall beplaced at a distance of 80 cm from the artificial mains networkand connected thereto by a lead of length not greater than 1 m.

(50) If the appliance is supplied with a flexible lead, the voltagesshall be measured at the plug end of the lead. The length of thelead in excess of the 80 cm separating the appliance from theartificial mains network shall be folded back and forth so as toform a bundle not exceeding 30 cm to 40 cm in length.

Methods of Measurement of interference power from Mains operatedappliances (30 - 300 MHz)

(51) It is generally considered that for frequencies above 30 MHz thedisturbing energy produced by appliances and similar devices ispropagated by radiation to the disturbed receiver.

(52) Experience has shown that the disturbing energy is mostlyradiated by the portion of the mains lead near the appliance. Itis therefore agreed to define the disturbing capability of anappliance as the power it could supply to its mains lead. Thispower is nearly equal to that supplied by the appliance to asuitable absorbing device placed around this lead at the positionwhere the absorbed power is at its maximum.

(53) The measurement is basically a measurement by substitution.

(54) Calibration is accomplished with a standard laboratory-typesignal generator having a 50 fl output impedance. This impedancechoice has been justified theoretically.

12

Measurement procedure

(55) The appliance to be tested is placed on a non-metallic table atleast 40 cm from other metallic objects and the mains lead isstretched in a straight line for a distance sufficient to accom-modate the measuring device, and to permit the necessarymeasuring adjustment of position for tuning. The measuring deviceis placed around the mains lead so as to measure a quantity pro-portional to the interference power on the line, and present tothe appliance an effective impedance having a resistive componentbetween 100 Q and 250 Q.

(56) It shall also provide adequate attenuation of interference con-ducted along the mains lead from the mains supply.

2.4.1.2 Limits -

(57) Limits only apply to regulating controls using current below 16 Aand for motors - separate as well as built-in - up to 2 kW.

TABLE I Limits for the frequency range 0.15 - 30 MHz.

Frequencyrange

MHz

0.1 5 to 0.50

0.50 to 5

5 to 30

Electrical household appliances andequipment causing similar interference

(sec Figure I)

dB(uV)

Decreasing linearly with the logarithmof the frequency from 66 to 56

56

60

Regulating controls incorporating semiconductordevices

At mainsterminals

(see Figure 1)

dB(iiV)

Decreasinglinearly with thelogarithm of thefrequency from66 to 56

56

60

At loadterminals

dB(jiV)

80

74

74

At additionalterminals

dB(»iV)

SO

74

74

TABLE II Limits for the frequency range 0.15 - 30 MHz.

Frequencyrange

MHz

0.1 5 to 0.35

0.35 to 5

5 to 30

Portable tools

Rated power of motor®

Not exceeding700 W

dB(nV)

Decreasing l incafrequency fror

66 to 59

59

64

Above 700 Wand not

exceedingI O O O W

dB(nV)

riy with the logamfr1

n

70 to 63

63

68

Above ! 000 Wand not

exceeding2000W

dB(aV)

imof the

76 to 69

69

74

* The power of any heating device Is to be excluded, for instanceheating power in a blower for plastic welding.

TABLE III Limits for the frequency range 30 - 300 MHz.

Frequencyrange

MHz

30to300

Interference power limits 30 MHz to 300 MHz

Household andsimilar appliances

dB(pW)

45 to 55increasing l inear ly

with frequency

Portable tools

Rated mains power*

Up to and including700 W

dB(pW)

45 to 55increasing l inearly

with frequency

Above 700 W up toand including 1 000 W

dB(pW)

49 to 59increasing linearly

with frequency

Above 1 000 W up toand including 2 000 W

dB(pW)

55 to 65increasing linearly

with frequency

* The power of any heating device is to. be excluded, for instanceheating power in a blower for plastic welding.

(58) Limits for discontinuous interference are relaxed compared withthose for continuous interference. The relaxation depends on theclick rate "N" (number of clicks per minute). A click "N11 isdefined as an impulse which exceeds the limit for continuousinterference.

14

The relaxation amounts to:

30dB = 20 Iog10 -

Observation time (T):

1) The number of minutes to produce 40 clicks or2) 2 hours

which of the event is less.

Click rate (N) :

(59) The allowable number of clicks above the increased limit is 25%.

2.4.1.3 national legislation

(60) In this section information is given about legal status of RFIrequirements and approval procedures in some of the most impor-tant countries. The trends of RFI requirements are that more andmore legislation will come up.

USA

(61) No mandatory limits in use.

(62) Recommendations about RFI are given by the American NationalStandards Institute (ANSI). Special interest is given to commit-tee C63. This committee constantly follows the work of CISPR andthere is a tendency to adopt the recommendations of CISPR. AlsoFCC is monitoring the growing number of RFI problems. In Part 15and Part 18 specifications for incidentally radiating equipmentare set forth, but household appliances are not explicitly men-tioned. However, various organizations are appealing to FCC tointroduce legislation for such equipment.

Europe

(63) The EEC has issued Document 82/499/ECC. This document is basedon CISPR Publication 14. The limits are mandatory in all membercountries. It is not necessary to forward any sample to the au-thorities for type approval, but it must be verified that theproduct complies with the regulations. Furthermore, it must bewritten in the instruction manual or in the warranty card in alllanguages of the member countries that the product complies withthe EEC Directive 82/499/EEC. Alternative type approvals can begranted by the authorities in every member country. A permissionto put on a special mark showing that the product complies withthe regulations is then given. In this case no written statementin the manual is necessary. Among some countries a mutual recog-

nition of national marks exist. This is the case between Denmark,Germany and Italy. Also independent test houses are recognizedby some authorities so that RFI marks can be obtained on thebasis of their test reports.

(64) Sweden, Norway, Austria and Switzerland follow CISPR8s Publica-tion even though .they are not members of the EEC and the limitsare mandatory.

Canada

(65) CSA standard C108.54 describes methods of measurements and limitsfor radio frequency interference. The Canadian authorities haveadopted CISPR1s recommendations and the limits are mandatory.

Australia

(66) It is supposed that the authorities follow the recommendationsfrom CISPR. It is not known if the limits are mandatory.

2.4.2 Standards for radio and television receivers

(67) Due to the local oscillator in radio and television receivers,these devices are potential RFI sources. Therefore, limits havebeen set up to control the radiation from these receivers.

(68) Internationally, the measuring methods are given in IEC Publica-tion 106. Three different measurements are described:

Local oscillator radiationLocal oscillator voltage on aerialterminalsTime base terminal voltage limits

(ref. FIG. 4)

(69) The radiation shall be measured on an outdoor measuring site freeof any reflecting objects. The site attenuation shall meet therequirements given in IEC 106. The time base terminal voltage ismeasured across an artificial mains network as described in CISPRPublication 16. The A network *), which makes it possible tomeasure both the symmetrical and asymmetrical interferencevoltage, shall be used.

(70) The limits for the devices, which have to comply with the stan-dard, are given below.

This network w i l l be replaced by a V-network in future standards.

16

RADIO AND TELEVISION SETS

EXTERNAL ARIAL

TERMINALS'

INTERFERENCEVOLTAGE IdBnV)80 - lOOOflHz

MAINS PLUG

INTERFERENCE VOLTAGE (dBMV)ISO - 1605kHz

FCC VOLTAGE AT THE INTERMEDIATE FREQUENCY AND ITSHARMONICS INJECTED INTO THE MAINS

RADIATED FIELDSTRENGTH luV/m)

80 - 1000MHz

FTZ SUSCEPTIBILITY

ElEKTRONIKCENTRALEN-

FIG. 4 RFI measurements on radio and television sets.

2.4.2.1 Radiation

Television receivers working in television broadcast channelsbelov 300 MHz

(71) Local oscillator fundamental frequency: 57 dB (uV/m). If a stan-dard intermediate frequency is used, this limit can be relaxed,on a national basis, to 66 dB (jiV/m) above 200 MHz.

(72) Harmonics below 300 MHz.- 52 dB (uV/m)Harmonics above 300 MHz: 56 dB (uV/m)

Television receivers working in television broadcast channelsbetween 300 MHz and 1000 MHz

(73) Local oscillator fundamental frequency in the range 300 MHz: 57dB (pV/m). If a standard intermediate frequency is used, thislimit can be relaxed, on a national basis, to 70 dB (uV/m).

17

(74) Harmonics up to 1000 MHz: 56 dB (yV/m)

FM sound radio receivers: Local oscillator radiation

Local oscillator fundamental frequency: 70 dB (yV/m)Harmonics below 300 MHz : 52 dB (yV/m)Harmonics above 300 MHz : 56 dB (yV/m)

2.4.2.2 Voltage on aerial terminals

(76) Note: The limits refer to a nominal terminal impedance of 75 2.For receivers having other values, the corresponding voltagelimits, calculated on a constant power basis, apply.

Television receivers working in television broadcast channelsbelow 70 MHz

(77) Local oscillaator fundamental frequency: 55 dB (yV)Harmonics below 300 MHz : 50 dB (yV)Harmonics above 300 MHz : 52 dB (yV)

Television receivers working in channels allocated to televisionbroadcast channels between 70 MHz and 300 MHz

(78) Local oscillator fundamental frequency: 60 dB (yV)Harmonics below 300 MHz : 50 dB (yV)Harmonics above 300 MHz : 52 dB (yV)

Television receivers working in channels allocated to televisionbroadcast channels between 300 MHz and 1000 MHz

(79) Local oscillator fundamental frequency: 66 dB (yV)

FM sound broadcast receivers: Local oscillator voltage on theaerial terminals

(80) FM sound broadcast receivers working in channels below 300 MHz.

Local oscillator fundamental frequency: 66 dB (yV)Harmonics below 300 MHz : 50 dB (yV)Harmonics above 300 MHz : 52 dB (yV)

18

2.4.2.3 Interference at the mains terminal of television receivers

Symmetrical

Asymmetrical

Frequency rangekHz

150500

500 - 1605

150500

500 - 1605

Limits

59 dB (yV)46 dB (yV)46 dB (yV)

56 dB (yV)52 dB (yV)52 dB (yV)

Note

Decreasing linearlywith frequency150 - 500 kHz

Decreasing linearlywith frequency150 - 500 kHz

(81) Time-base terminal voltage, but not exclusively produced by thatsource (see Sub-clause 5.1.1 of CISPR Publication No. 13)

(82) For FM receivers to be used in cars only the aerial terminalvoltage has to be measured.

2.4.2.4 national legislation

(85) The ISC 106 measuring method is generally accepted by allcountries. The allowable interference is dependent on nationallegislation. However, two major countries - USA and West Germany- demand additional measurements to those described in IEC 106. Ashort description of these measurements is given in the followingsections.

(84) Before marketing the products a certification or a registration,which in this case is identical,- is necessary. The permission tomarket the products is based on information and test report sub-mitted by the manufacturer or the distributor. In Europeancountries the registration is only given to national distributorsor manufacturers. A foreign manufacturer cannot achieve anyregistration. In the USA it is possible for a foreign manufac-turer to get a certification which gives a permission to markethis products in the USA.

19

USA

The national regulation for radio and television receivers is FCCPart 15 Subpart C. This standard accepts among others themeasuring procedure for radiation described in IEC 106, but alsocalls for a measurement of conducted emission on the mains ter-minals of FM receivers. The terminal voltages shall be measuredin the frequency range 0.45 - 25 MHz across a 50 fi/5 jiH artifi-cial mains network.

Interference voltage at mains terminals

Type ofreceiver

Televisionreceivers

FM-receivers2/

Frequency rangeMHz

0.45 - 25

0.45 - 99 - 1010 - 25

Limit

100

1000 100 - 1000

1000

1) Linear interpolation in |iV.

2) These liwits are furthermore valid for:a) Other receivers that tune in the range 30 - 890 MHz.b) Receivers used with garage door openers in the

range 30 - 890 MHz.

West Germany

(86) The national standard for radio and television receivers isVDE 0872. Besides the emission also the immunity has to betested. Limits have been set up both for the conducted suscep-tibility and the radiated susceptibility. The measuring methodsare rather complicated (ref. VDE 0872 Teil 5 or DIN 45305, fordetails). The subject immunity to interferring signals for radioand television receivers is also discussed in CENELEC, but thediscussion is in an early phase, and consequently internationallegislation cannot be expected in the very near future.

2.4.3 Standards for walkie-talkie and similar transmitters

(8?) In most countries transmitters such as walkie-talkies, cordlesstelephones, wireless microphones etc. have to be approved bythe national post and telegraph authorities before they can bemarketed. In every single country a sample has to be submitted fortest. No mutual agreement of test results exists between dif~

20

ferent oraganizations or authorities. Every single countrydemands a sample for making their own tests.

(88) Communication equipment can be devided into five groups:

Private transceivers (Walkie-talkies)Land mobile communicationMaritim communicationCordless telephonesPublic mobile telephone systems

(89) Private transceivers are those communication units, which can besold without special license for the individual user. A generallicense in form of a type approval is necessary before the pro-duct can be sold. All other types of communication equipment haveto be licensed for the individual users.

(90) Each of the above mentioned groups is covered by its own set ofrequirements, and many countries have their own requirements. Theprimary interest is directed towards:

Radiated powerOperating frequencySpurious emission.

(ref. FIG.- 5)

WALKIE-TALKIE AND SIMILARS

FREQUENCY STABILITY

CHANNEL SELECTIVITY

RADIATED POWER (dBn)TRANSMITTING FREQUENCY

SPURIOUS EMISSION25MHz - 4GHz

ElEKTRONIKCENTRALEN-

FIG. 5 Measurements on walkie-talkies.

21

(91) In Europe an ongoing work for harmonization of the requirementsis taking place inside the organization CEPT. A set of the Danishrequirements, which have incorporated the recommendation fromCEPT has separately been submitted to the Industry Department ofHong Kong Government.

(92) No harmonization exists between Europe and the USA. The authori-ties in the USA are more liberal compared with those in Europe.The national standard is FCC part 15, subpart D. Before marketingthe product a certification is necessary, but this can be basedon the manufacturer's test results. A list of addresses of thePostal Authorities is given in APPENDIX 2 of this report.

2.4.4 Standards for computing devices

(93) Computing devices operate with binary codes, which are pulsedsquare wave electrical signals. Generally, a clock generator isbuilt into the computing devices to synchronize the operation ofthe digital circuits. The signal from the clock generator is nota smooth sine wave. Therefore a number of harmonics of the fun-damental frequency are generated as well. Both the binary pulsedsignals and the harmonics of the clock generator frequency maycause interference to the reception of radio and television. Theinternational standard, which describes the measuring methods andgives recommended limits, is:

CISPR Publication 22, First edition 1985

Limits and Methods of Measurement of Radio InterferenceCharacteristics of Information Technology Equipment (ITE).

(94) According to the standard, computing devices are subdivided intotwo categories denoted Class A and Class B.

Class A equipment

(95) Class A equipment is information, technology equipment whichsatisfies the Class A interference limits but does not satisfythe Class B limits. In some countries, such equipment may be sub-jected to restrictions on its sale and/or use.

(96) Note: The limits for Class A equipment are derived for typicalcommercial establishments for which a 30 m protection distance isused. The Class A limits may be too liberal for domestic estab-lishments and some residential areas.

Class B equipment

(97) Class B equipment is information technology equipment whichsatisfies the Class B interference limits. Such equipment shouldnot be subjected to restrictions on its sale and is generallynot subject to restrictions on its use.

22

Note: The limits for Class B equipment are derived for typicaldomestic establishments for which a 10 m protection distance isused.

2.4.4.1 Measuring methods

(99) Interference measurements on ITE equipment involves 3 mainprocedures:

Interference voltage on mains leadsInterference magnetic field 0.01-30 MHz(only VDE)Interference electrical field 30-1000 MHz J

(ref. FIG. 6)

INFORMATION TECHNOLOGY EQUIPMENT (ITE)(COMPUTERS)

/ VOC CLASS B \

[ UNSHIELDED SIGNAL CABLES' ]

I INTERFERENCE VOLTAGES /

\ 0.0! - 30MHz /

RADIATED FIELDSTRENGTH (uV/m)30 -1000MHz(VDE'O.OI-30MHz)

MAINS PLUG

INTERFERENCE VOLTAGE ldBMV)

0.01 - 30MHz

FIG. 6 RFI measurements on ITE.

ElEKTRONIKCENTRALEN-

Method of measurement of terminal interference voltage

(100) Measurements shall be carried out using quasi-peak and averagedetector receivers. Both detectors may be incorporated in asingle receiver and measurements carried out by alternativelyusing the quasi-peak detector and the average detector.

Measuring receivers

(101) Receivers with quasi-peak detectors shall be in accordance withsection one of CISPR Publication 16: Specification for RadioInterference Measuring Apparatus and Measurement Methods.Receivers with average detectors shall be in accordance withClause 23, Section Five, of CISPR Publication 16.

Artificial mains network

(102) An artificial mains network is required to provide a definedimpedance at high frequencies at the power input terminals andalso to provide isolation of the circuit under test from theambient radio-frequency energy on the power lines,

(103) A network with a nominal impedance (50 ft/50 yH) as defined inSubclause 8.3.3., section two, of CISPR Publication 16 shall beutilized.

(104) Connection of the test unit to the artificial mains network isrequired and the test unit is located so that the distance bet-ween the boundary of the test unit and the closest surface ofthe artificial mains network is 0.8 m.

(105) Where a mains flexible cord is provided by the manufacturer thisshall be 1 m long or if in excess of 1 m the excess cable isfolded back and forth as far as possible in order to form abundle not exceeding 0.4 m in length.

(106) Where a mains cable is specified in the manufacturer's installa-tion instructions a i m length of the type specified shall beconnected between the test unit and the artificial mains network.

(107) The test unit shall be arranged and connected with cables termi-nated in accordance with the manufacturer's instructions. Earthconnections, where required for safety purposes, shall beconnected to the reference earth point of the network and wherenot otherwise provided or specified by the manufacturer, shall be1 m long and run parallel to the mains connection at a distanceof not more than 0.1 m.

(108) Other earth connections (e.g. for EMC purposes), either speci-fied or supplied by the manufacturer for connection to the sameultimate terminal as the safety earth connection, shall also beconnected to the reference earth of the network.

(109) It may not be possible to measure at some frequencies because ofconducted ambient noise which couples from local broadcast ser-vice fields. A suitable additional radio-frequency filter may beinserted between the artificial mains network and the mainssupply, or measurements may be performed in a shielded enclosure.The components forming the additional radio-frequency filtershould be enclosed in a metallic screen directly connected to

24

the reference earth of the measuring system. The requirementsfor the impedance of the artificial mains network should besatisfied at the frequency of the measurement, with the addi-tional radio-frequency filter connected.

Ground plane

(110) The test unit, if unearthed and non-floor-standing, shall beplaced 0.4 m from a reference ground plane consisting of a hori-zontal or vertical metal surface of at least 2 m by 2 m and shallbe kept at least 0.8 m from any other metal surface or otherground plane not being part of the test unit. If the measurementsis made in a screened enclosure, the distance of 0.4 m may bereferred to one of the walls of the enclosure.

(111) Floor-standing test units are subject to the same provisions withthe exception that they shall be placed on a floor, the point(s)of contact being consistent with normal use. The floor may be ofmetal but shall not make metallic contact with the floor sup-ports of the test unit(s). A metal floor may replace the refe-rence ground plane. The reference ground plane shall extend atleast 0.5 m beyond the boundaries of the test unit and haveminimum dinemsions of 2 m by 2 m.

(112) The reference earth point of the artificial mains network shallbe connected to the reference ground plane with a conductor asshort as possible.

Method of measurement of radiated interference field strength

(113) The radiated emission shall be measured on an outdoor measuringsite free of any reflecting objects apart from the groundplane. The minimum size of the test site shall be the area of anellipsis where the two focal points are separated by a distancecorresponding to the prescribed measuring distance. The testobject shall be rotated for maximum radiation and the receivingaerial shall be varied in a search range between 1 m and 4 mabove the ground. The radiation shall be measured both withhorizontal and vertical polarization of the receiving aerial.

Ground plane

(114) Floor-standing test units shall be placed as close as possible tothe ground plane of the test site. Portable test units shall beplaced on a non-metallic table 0.8 m above the ground plane. Ametal ground plane shall be inserted under the test unit on thenatural ground plane and it shall extend at least 1 m beyond theperimeter of the test unit at one end, and at least 1 m beyond themeasurement aerial at the other end. The ground plane shall haveno voids or gaps that are a significant fraction of a wavelengthat the highest frequency. The recommended maximum mesh size forperforated metal planes is 0.1 X at 1000 MHz (above 30 mm).

25

2.4.4.2 Limits

Limits of mains interference voltage

(115) The test unit shall meet the limits in TABLES IV or V includingthe average limit and the quasi-peak limit when using, respec-tively, an average detector receiver and a quasi-peak detectorreceiver. If the average limit is met when using a quasi-peakdetector receiver, the test unit shall be deemed to meet bothlimits, and measurement with the average detector receiver isunnecessary.

TABLE IV Limits of mains terminal interference voltage in thefrequency range 0.15 - 30 MHz for Class A equipment.

Frequency range(MHz)

0.15 to 0.500.50 to 30

LlraiU (dB (nV)J

Quasi-peak

7973

Average

6660

The lower limit shall apply at the transition frequencies.

TABLE V Limits of mains terminal interference voltage in thefrequency range 0.15 - 30 MHz for Class B equipment.

Frequency range(MHz)

0.15 to 0.500.50 to 5

5 to 30

UmiU [dB (jiV)l

Quasi -peak

66 to 565660

Average

56io464650

The lower limit shaii appiy at the transition frequencies.

Limits of radiated interference field strength.

TABLE VI Limits of radiated interference field strength in thefrequency range 30 MHz - 1000 MHz at a test distanceof 30 m for Class A equipment.

Frequency range(MHz)

30 to 230230 to 1 000

Quasi-peak limitsIdfl (*iV/m)l

3037

The lower limit shall apply at the transition frequency.

26

TABLE VII-Limits of radiated interference field strength in thefrequency range 30 - 1000 MHz at a test distance of10 m for Class B equipment.

Frequency range(MHz)

30 to 230230 to 1 000

Quasi-peak limits(dBUiV/m)|

3037

The lower itmtt shall apply tt the iransidon frequency.

(116) Note: If the field strength measurement cannot be made because ofhigh ambient noise level or for other reasons, measurement may bemade at a closer distance, e.g. 10 m or 3 m.

(11?) An inverse proportionality factor of 20 dB per decade should beused to normalize the measured data to the specified distance fordetermining compliance. Care should be taken in measurement oflarge test units at 3 m at frequencies near 30 MHz due to nearfield effects.

2.4.4.3 National legislation

(118) More and more countries have introduced legal requirements forradiation from computing devices. Basically, the measuringmethods are the same, but some countries specify an extended fre-quency range compared with others, and they also specify someadditional measurements.

2.4.4.3.1 USA

(119) The national regulation is FCC Part 15 Subpart J. For regulatorypurposes, the FCC has divided computing devices into two cate-gories based on how the computer is marketed and used:

Class A This is a computer marketed for use in a busi-ness/commercial/industrial area.

Class B This is a computer marketed for use in a resi-dential (home) environment. The fact that sucha computer is also used in business areas doesnot change the classification. Examples ofClass B computing devices are personal computers,electronic games for use in the home and electro-nic organs.

27

(120) Two squxpment authorization procedures are established for com-puting devices:

CertificationVerfication

(121) These methods are not optional for the manufacturer. Certifica-tion is mandated (mandatory) for most Class B equipment whereasverification applies to Class A equipment and some Class Bequipment.

Certification

(122) Under this procedure the applicant fills in an application on aspecial FCC form. Normally, this application is filled in by themanufacturer who assumes the responsibility for compliance of theequipment with FCC rules. However, other parties such as an im-porter or a vendor, may assume the responsibility for compli-ance, too, and may fill in the application. A detailed report ofmeasurement, showing that the device is in compliance with thelimit for Class B equipment, must be attached to the applicationfor certification.

(123) If the submitted information is accepted fry the FCC a Grant ofEquipment Authorization will be issued and an FCC identifierwhich shall be attached permanently and located conspicuously onthe equipment. The Grant is an authorization to initiate marketing.

Labelling requirements

(124) A Class B computing device subject to certification by the Com-mission shall have the following labelling.

"Certified to comply with Class B limits,Part 15 of FCC Rules. See instructions ifinterference to radio reception is suspected15

(t25) For a Class B computing device subjected only to verification ofcompliance by the manufacturer, the following or similar state-ment is optional:

"Complies with the limits for a Class B computingdevice pursuant to Subpart J of Part 15 of FCC rules11.

Information to user

(126) Information shall be provided to the user of a Class B acomputingdevice about the interference potential of the device and simplemeasures that can be taken by the user to correct the interfe-rence. This information shall b.e included in a conspicuousplace in the instruction manual. This is not required for anextremely low power, miniature computing devices such as anelectronic digital watch.

28

(127) T^e following language may be used to provide the required infor-mation, but any language that conveys the same meaning and canbe understood by an average person without a technical education,may be used:

This equipment generates and uses radio frequency energy andif not installed and used properly, that is, in strictaccordance with the manufacturer's instructions, may causeinterference to radio and television reception. It has beentype tested and found to comply with the limits for a ClassB computing device in accordance with the specifications inSubpart J of Part 15 of FCC Rules, which are designed toprovide reasonable protection against such interference in aresidential installation. However, there is no guaranteethat interference will not occur in a particular installa-tion reception, which can be determined by turning the equip-ment of and on, the user is encouraged to try to correct theinterference by one or more of the following measures:

Reorient the receiving antennaRelocate the computer with respect to the receiverMove the computer away from the receiverPlug the computer into a different outlet so thatcomputer and receiver are on different branch circuits

If necessary, the user should consult the dealer or anexperienced radio/television technician for additionalsuggestions. The user may find the following bookletprepared by the Federal Communications Commission helpful:

"How to Identify and Resolve Radio-TV Interference Problems".

This booklet is available from the U.S. Government PrintingOffice, Washington, DC 20402, Stock No. 004-000-003435-4".

(128) For personal computers the following warning statement shall beconspicuously located in bold letters in the instruction manual:

WARNING: This equipment has been certified to complywith the limits for a Class B computing device, pur-suant to Subpart J of Part 15 of FCC Rules, Only peri-pherals (computer input/output devices, terminals,printers, etc.) certified to comply with the Class Blimits may be attached to this computer. Operationwith non-certified peripherals is likely to result ininterference to radio and TV reception.

Verification

(129) Under this procedure the manufacturer or the importer must testthe computing device to determine whether it complies with theapplicable FCC technical standards. As soon as the manufacturerhas ensured himself that the device complies with the standardsand is labelled as required, he may start marketing the device.

(130) Under verification, no filing with the Commision is required. TheCommission may require the manufacturer of the equipment, subjectto verification, to submit a report of the measurements carriedout, a sample of the computing device or both.

(131) No Grant of Equipment Authorization is issued by the Commissionfor devices subject to verification. Accordingly, no FCC iden-tifier or the term "FCC ID" is permitted on the label of verifiedequipment.

Labelling requirements

(152) Each computing device which has been verified as complying withthe Class A limits shall have a label permanently attached in aconspicuous location easy for the user to observe. The followingstatement is stated on the label:

"This equipment complies with the requirements in Part 15 ofFCC Rules for a Class A computing device. Operation of thisequipment in a residential area may cause unacceptableinterference to radio and TV reception, requiring theoperator to take whatever steps neccessary to correct theinterference".

Information to user

033) The following warning or similar statement shall be provided in aconspicuous location in the operator's manual so that the user ofa Class A computing device is aware of its interference potential.Additional information about corrective measures may also be pro-vided to the user of the manufacturer's option.

WARNING: This equipment generates, uses, and can ra-diate radio frequency energy and if not installed andused in accordance with the instruction manual, maycause interference to radio communications. It hasbeen tested and found to comply with the limits for aClass A computing device pursuant to Subpart J of Part15 of FCC Rules, which are designed to provide reason-able protection against such interference when operatedin a commercial environment. Operation of this equip-ment in a residential area is likely to cause inter-ference in which case the user at his own expense willbe required to take whatever measures may be requiredto correct the interference.

Limits

(134) Limits are given for both conducted emission and radiatedemission.

Conducted emission

FrequencyMHz

0.45 - 1.6

1.6 - 30

Class AdBdyV

60

70

Class BdByV

48

48

Radiated emission

FrequencyMHz

30 - 88

88 - 216

216 - 1000

ClasdBpiV/m at 30 m

30

34

37

s AdByV/m at 3 m

50

54

57

Class BdByV/m at 3 m

40

44

46

Measuring methods

(135) The measuring method is as described in SECTION 2,4.4.1, however,if the measuring distance is more than 10 m, the receiving aerialshall be varied in a search range between 2 m and 6 m, instead of1 m and 4 m.

2.4.4.3.2 West Germany

(136) The national standard is VDE 0871. In the same way as for the USA,the computing devices are divided into two categories. (In fact athird category exists, which is used for measurements on largesystems at the user's installation):

Class 1 where an individual license is required by thelocal Telecommunication Office for every systemor unit marketed.

Class B where a general license is granted.

(15?) Two different authorization procedures are given for the twoclasses of equipment. In principal, the manufacturer/importer hasthe choice whether his customer shall make use of an IndividualLicense or a General License. However, if a mass product withminor changes can be brought into a standard to meet the moresevere requirements of VDE 0871 limit B, the ZZF may refuse anapproval under the Individual License and may require to make useof the General License. This is done in order to avoid the highadministrative effort in case of Individual License.

Individual license

(133) Under this procedure an application is filled in by the opera-tor/user and a license is granted by the local Telecommunica-tion Office at the location where the equipment will be used.

(139) The license is only granted on the basis of a previous type testand certification performed on application of the importer by theVDE Testing and Certification Institute. The certificate is sub-mitted to the ZZF for approval of a FTZ SERIAL TEST No., whichhas to be attached to the equipment. Only certificates from VDEare accepted by the ZZF.

General license

(140) Under this procedure no application from the operator/user of thecomputing device is required, provided that the manufacturer orimporter, respectively, ensures that there is compliance betweenthe requirements of VDE 0871 for Class B and the decree("Verfugung") 1046/1984 of the Federal Minister for Post andTelecommunications.

(141) A Class B computing device can be authorized one of two ways:

1) marked with a VDE Radio Protection Mark (F-Mark) withthe subscript "0871-B11. This license can only begranted by the VDE after a positive type test attheir facilities.

2) provided with a Manufacturer's or Importer's de-claration in German language on the equipment itself,in the instruction manual or on the warranty card,confirming that the equipment is in conformity withthe before-mentioned radio interference suppressionrequirements.

Moreover a registration at the ZZF is required. Byrequest of the ZZF, compliance with the requirementshas to be demonstrated by a test report on the basisof a manufacturer's self-certification. In this respectit is sufficient to have available the correspondentmeasuring results.

Limit

(142) Limits are given both for conducted emission and radiatedemission. The radiated emission is also measured in the frequencyrange 0.01 - 30 MHz. In this frequency range the field strengthis measured in the near field, where the ratio between theelectric field vector (E) and the magnetic field vector (H) isnot specified by the characteristic impedance of free spaceZ0 = 377 J2). In this frequency range only the magnetic field ismeasured. However, the measuring instrument is calibrated in

Conducted emission

FrequencyMHz

0.01 - 0.150.15 - 0.50.5 - 30

Class AdByV

mm

6660

Class BdByV

79 to 57,55448

Note; The limit decreases linearly with the logarithm of the frequencyin the range 0.01 - 0.15 HHz.

Radiated emission

FrequencyMHz

0

1

304168174230

470760

.01 - 1

- 30

4168

- 174- 230- 470

- 760- 1000

Class AdBuV/m dByV/m

(30 m) (100 m)

34

34

5430543054

452)59 to 57 l)2)

Class BdByV/ra dByV/m

(30 m) (10 m)

91.5 toOsi.s

51.5 to030

3434343434

4040

dByV/m

(30 m)

34

34

Notes: *) The limit decreases linearly with the logarithm of thefrequency.

2) Measuring distance 10 m.

Measuring method

(145) Basically, the measuring method is the same as described inSECTION 2.4.4.1. However, some additional measurements are re-quired by the VDE. Firstly, radiation measurements have to bemade in the frequency range 0.01 - 30 MHz. Secondly, terminalvoltages have to be measured on the signal line connectors ofa Class B computing device, if the signal cables to be used arenot screened. Normally, these measurements will always producevalues exceeding the limit. Therefore, it is an indirect way tomake it mandatory to screen all signal cables. Finally, if themains interference from a Class B computing device is less than5 dB below the limit and the computing device has a ground wire,measurements on the frequencies in question shall be repeatedwith the ground wire connected to the artificial mains networkthrough an inductor of 2 mH.

34

2.4.4.3.3 United Kingdom

(144) The national standard is BS 6527, 1984. On the whole it is inagreement with CISPR Publication 22. The standard is not man-datory by now. Therefore no authorization of computing devices isrequired.

2.4.4.3.4 Sweden

(145) Sweden has no national standard covering all computing devices,but there exists a standard for home computers and Televisiongames. This national standard is SEN 471010. The measuring methoddiffers from the international standard in the way that theemission is measured on all external cables by using an absorbingclamp instead of measuring the radiation by antennas. The stan-dard is mandatory.

2.4.4.3.5 Denmark

(146) ^he national standard is DS 5101: 1986. Basically it is inaccordance with CISPR Publication 22, but besides the two classesgiven in CISPR, a third class with more restricted levels for theemission is given and also possibility to define even moresevere limits is given.

(147) There are no mandatory authorization requirements for computingdevices, but the Post and Telecommunications authorities candemand the user to stop the operation of an equipment if theradio or television reception is disturbed.

(148) Mandatory requirements are under preparation.

2.4.4.3.6 EEC

(149) Work is going on with harmonization of the national legislation.This Work is not expected to be completed in the first couple ofyears. However, a harmonization will come and an EEC directivewhich probably will be based on CISPR 22 will be issued. Thismeans that the future authorization procedure for computing devi-ces in western Europe will be carried out as for householdappliances.

2.5 Future development trends

(1.50) The future trends of RFI requirements are that more and morelegislation will come up. The tendency is also that the authori-ties will adopt CISPR1s recommendation which will result in aharmonization of the RFI requirements at least in the technicalrespect.

35

/151) The trends are going in the direction to use more and more "ve-rification11 based on test results from independent test houses.It is essential that the test houses have a quality assurancepolicy and that their instruments are subject to regulary cali-bration procedures.

(152) UP <to no¥ t^e susceptibility requirements for electronic productshave mainly been a matter between the manufacturer and the indi-vidual consumer. Only Germany has legal immunity requirements forradio and television sets. Other countries have hardly any legalsusceptibility requirements. However, more and more suscepti-bility requirements will come up in the future. As an example theOIML (Organisation Internationale de Metrologie Legale) has setup a number of specifications including EMC for electronicweighing instruments. The IEC has two technical committees, whichare very active producing EMC standards. These are TC 65 andTC 77. Without doubt susceptibility requirements, or at leasttests, will be common in the future.

(153) The increased use of electronics in all kinds of products makethem vulnerable to electrical interference, and malfunction mayoccur. If any, accidents occur due to the malfunction the manu-facturer can be hold responsible for the accident. Laws coveringproducts liability will come up in more and more countries.Therefore, it is important carefully to test a product forsusceptibility to electrical interference, before it is marketed.

56

3. AMD FACILITIES

(154) The facilities and the instrumentation mentioned in this chaptermake it possible to carry out measurements in accordance with thestandards given in CHAPTER 2.

(155) The survey will distinguished between test facilities and testinstrumentation. Facilities mean permanent installations neces-sary for the test such as shielded rooms, outdoor measuring siteetc. Instrumentation is the equipment such as receivers, antennae,artificial mains networks, which are used during the test.

(156) Besides, a listing of the instruments, the economic considera-tions and possible manufacturers of the instruments are given.

3.1 Instrumentation

(157) In this section the instruments necessary for the RFI measure-ments are mentioned. They are listed under headings of the dif-ferent kinds of measurements, such as conducted emission, radi-ated emission etc. Some of the instruments are used for more thanone type of measurement. In such cases the instrument is men-tioned more than once. This does not mean that any decision hasbeen made with regard to the necessity of having more than oneinstrument of the type in question. This matter will be discussedin the section concerning calibration and maintenance.

3.1.1 Conducted emission

(159) The artificial mains network (or LISN) is used to obtain a well-defined impedance across which the voltages are measured.

(159) The impedance charateristic of the most common used mains networkis shown in FIG. 7. This is the so-called 50 yH (and 50 fl) mainsnetwork. Another mains network which is used for the measurementof conducted emission according to FCC, is the so-called 5 yHnetwork. The impedance characteristic is shown in FIG. 8. The twomains networks can be used arbitrarily, provided that the read-ings obtained are corrected according to the curve given inFIG. 9. The correction varies from 10 dB at 450 kHz to 0 dB at2 MHz* Above 2 MHz no correction is required. The correction isbased on the relative impedance values of the 50 yH and the 5 yHmains network.

(160) it is recommended to purchase the 50 yH network, as this is themost commonly used. The network is available from several sup-pliers.

37

S H H O I D M Y Q I J I H I

FIG. 7 Impedance characteristic for a 50 yH mains network.

o2

Oz:IdZ)QUJo:

SWHO

FIG. 8 Impedance characteristic for a 5 yH mains network.

O

oo

H-o

(D(D

PJ

Ul

aBJ

enO

H.dt/1

rt

O

C o r r e c t i o n In dfi for 30 uH L I S N :Add co reeding* w i c h S uH LISNco o b t a i n va lues e q u i v a l e n t tothose cha t would be ob ta ined w i t ha 50 y H L I S N .

F R E Q U E N C Y ( M H r )

40

(161) The EMI meter is connected to the artificial mains network, andthe voltages on the mains terminals of the test object aremeasured. The EMI meter can either be a test receiver or aspectrum analyzer. The test receiver is a tunable frequencyselective RF voltmeter. The frequency selection already starts atthe front end of the receiver. Generally, spectrum analyzers donot use tuned receiver front ends. Therefore, this kind of EMImeters suffer from high spurious responses. The problems can beavoided by using a preselector in combination with a spectrumanalyzer.

(162) In order to permit some kind of signal recognition, the EMImeters are provided with a selection of several weighted detectorfunctions. In the test receiver these functions are built-in,whereas the spectrum analyzer normally must have external detec-tors added. A very important detector for interference measure-ments is the CISPR detector. This is primarily used where broad-band interference is to be measured, e.g. commutator noise. Ifthe interference is narrowband noise, the different detectorsgive the same readings (r.m.s. level).

(163) The principal advantage of the spectrum analyzers compared withthe test receiver is the large frequency coverage for a relati-vely small investment. Less emphasis is placed upon calibratingthe amplitude, especially for broadband emission sources. Infact, most spectrum analyzers offer only a small dynamic range toimpulsive signals. In contradistinction to this, the test recei-vers normally cover smaller frequency ranges, why more than onetest receiver is necessary in order to cover the frequency rangespecified in the standards. The receivers have a large dynamicrange, and the calibration facilities are very accurate. Anotherfact is that the test receivers are constructed to meet the stan-dards with respect to bandwidths e.g. 200 Hz, 9 kHz and 120 kHz,whereas spectrum analyzers have bandwidths, which slightly differfrom those, unless they have been especially constructed forradio interference measurements.

(164) Today the test receivers exist in two versions: a manually and anautomatically operating version. The manually operated receivershave dials for tuning the frequency, and are very easy to use.The automatically operated receivers are supplied with a data busconnector, and can be operated from a computer. By using the auto-matically operated test receiver you will achieve some of theadvantages of the spectrum analyzer. When the measurements arecarried out automatically, you will loose the "feeling11 with theresults. Therefore, care must be taken in having regulary cali-bration routines.

(165) In some cases the standards also prescribe mesaurements of inter-ference voltages on terminals other than the mains. For this pur-pose a line probe has to be used together with the EMI meter. Theline probe is simply formed as a capacitor (xc < 1500 ft) inseries with a 1450 Q resistor.

41

Discontinuous interference e.g. from contact function in refri-gerators, washing machines and thermostates is basically measuredin the same way as the continuous interference. Before the deci-sion whether the interference is discontinuous, it is necessaryto analyze the duration and the repetition rate of the inter-ference. For this purpose a digital interference analyzer hasbeen developed. The instrument is used in combination with atest receiver. In the near future it will only be required tomeasure discontinuous interference at frequencies below 30 MHz(today the interference also has to be measured at 45 MHz).

3.1.2 Radiated emission

(167) The EMI aeter for the radiation measurements can be either a testreceiver or a spectrum analyzer in the same way as for the con-ducted emission. Referring to the comments to the facilities, thetest receiver is much more easy to use on an outdoor measuringsite due to the ambient signal level than the spectrum analyzer.If a spectrum analyzer is used together with a preselector youwill have some of the advantages of the test receiver solution.The major part of the radiation faced with is narrowband emis-sion. Therefore a CISPR detector is not necessary.

(168) The antennae used are normally broadband or tuned. For the oscil-lator radiation measurements tuned dipoles are prescribed. Nor-mally, this kind of antenna is an adjustable dipole covering abroad frequency range. Standards for other kinds of radiationmeasurements accept the use of broadband antennae. To cover thespecified frequency range 25 - 1000 MHz usually two broadbandantennae have to be used.

(169) The antenna Bast for the receiving antenna shall have a height,which makes it possible to vary the antenna between 1 m and 4 mabove the ground (note: if the measuring distance is beyond 10 m,the antenna height has to be varied between 2 m and 6 m above theground plane). Masts where the antenna height automatically canbe varied are commercially available, but can easily be con-structed.

0?0) The turn table for relatively small test objects can also bedelivered by different suppliers, but again the construction isrelatively easy to carry out by yourself.

(171) The magnetic radiation is measured at frequencies below 30 MHz. Aloop antenna (or frame antenna; the physical form of the antennais not so important) is used together with an EMI meter. It isrecommended to use a test receiver as this generally has a sen-sitivity which is better than a spectrum analyzer. Alternativelya spectrum analyzer together with a preselector can be used.

42

3*1.3 Radiated power

(172) to absorbing clamp (MDS-clamp) is used to measure the RFI currenton the mains cable and/or other external cables from test objectsof small physical size. This test method is used instead ofmeasurements of the radiation by antennae. In order to have theequivalent power from the test object, the absorbing clamp has tobe calibrated in the test set-up. The read-out on the EMI meter(dBpiV) can then be converted to an equivalent power (dBpW).

(175) The EMI ffieter must have a built-in CISPR detector, or it must beconnected to such one, as the specified test method normally isused for broadband emissions.

3.1.4 Susceptibility test

(174) In order to be able to carry out susceptibility tests in accor-dance with FTZ regulations some additional instrumentation mustbe available.

A strip line is an antenna formed by two parallelplates, and is used for frequencies below 150 MHz.It is not available from any suppliers, but has tobe constructed, which is not very complicated.

1 signal generator of 5-10 W covering the frequencyrange 0.15 - 150 MHz.

A voltmeter with selectivity in the audio frequencyrange or with an external bandpass filter.

(175) A coupling network for the induced noise signal has to be con-structed by yourself.

3.1.5 Peripherals

Besides all the above listed equipment, which is dedicated forspecific test set-ups, it is necessary to make investments instandard laboratory instrumentation such as oscilloscope(s),voltmeters, etc. Furthermore, if the test house has to carry outinterference suppression for the clients, investments, which arenot negligible, have to be made in a number of standard mainsfilters, RF chokes, ferrit cores, capacitors etc.

3.2 Facilities

(177) The measurement of the conducted emission may be carried out inan ordinary laboratory if the size is adequate, but for reasonswhich will be explained later, a shielded room is recommended.

43

(178) If the conducted emission measurements are carried out in anordinary laboratory, it is necessary to have a ground plane of asize greater than two square meters as a reference for the mea-surement. It is also necessary to insert a filter in the mainssupply.

(179) For the measurement of interference power by a MDS clamp a mini-mum length of the laboratory of 6 m will be required (at 30 MHz,X/2 = 5 m).

(180) Instead of carrying out the conducted measurements in an ordinarylaboratory, it is recommended to use a shielded room. In this wayinterference from the ambients can be completely avoided. Thismakes it possible to use automatic measuring equipment withoutloosing any confidence to the result because of external inter-ferences.

(181) A shielded room is compulsory for all kinds of susceptibilitytests. Immunity test of radio or television receivers accordingto the FTZ regulations must take place in a shielded room.

(182) The relevant standards for RFI testing require the use of an openair test site for test of the radiated emission. It is necessarythat the ambient signal level is relatively low to ensure thatthe measured interference originates from the device under testand not from irrelevant sources. The test site shall be situatedon a flat area, and a considerable distance from buildings orother reflecting objects shall be provided for. The reflectionfrom the ground must be perfect in order to meet the specifiedrequirements for the site attenuation. This problem is oftensolved by having a metal ground plane covering the entire testsite. The prescribed measuring distances are 3 m, 10 m, 30 m, and100 m. In most cases a test distance of 10 m is sufficient. Onlymeasurements of large objects must be carried out at greater di-stances. According to FCC, equipment subject to a 30 in measuringdistance may be measured at a distance of from 3 m to 30 m, pro-vided that the results are extrapolated to equivalent signal at30 ra utilizing an inverse distance extrapolation factor (20 dB/decade). The same point of view is not taken by the VDE. A con-version from 3 m distance to a distance of 10 m is not accepted.

(183) Some practical matters are associated with open air test sitetesting. Firstly, it will be time-consuming and costly if person-nel and specimens have to be brought back and forth, in case ofthe open area test site being separated from the rest of the testhouse. Secondly, bad weather conditions may require cancelling orpostponing of planned tests. Finally, the weather conditionscause corrosion or mechanical destruction of permanent installa-tions such as ground plane, antenna mast, and the like.

44

(184) The first problem can easily be solved by having the outdoormeasuring site close to the test house. In some cases it will beideal to have outdoor measuring site on top of a test house withflat roof, where the entire surface is covered with metal plates.In this way the problem with reflecting objects might be solvedmore easily as most objects are below the surface of the groundplane. If the test site has to be used for large objects of heavyweight, it is more convenient to place the measuring site nearthe ground floor, as the transportation to and from the roofmight be difficult.

(185) The second and the third problem could be solved by covering theentire measuring site with a non-conducting cover, A possiblesolution could be a glassfiber dome. The problems could also besolved by having a shelter, where the device under test could beplaced during the measurements. The mast for the receivingantenna could remain outside the shelter.

(186) The radiation has to be measured from all directions of the de-vice under test. This requirement necessitates a rotable plat-form. While the device is rotated, the receiving antenna has tobe moved up and down between 1 m and 4 ra. In order to obtain acentral control, the elevation and the rotation can be motorizedand supplied with a remote -control.

(187) Ideal open air locations rarely exist, A spectrum of distinctfrequencies for the licensed transmitters will always exist,especially in urban areas. Due to this fact, automatically ope-rated measuring receivers cannot be used on an open air testsite, because distinction between signals from transmitters andinterference signals from the device under test cannot be made bythe automatically operated receiver. Instead a manually operatedmeasuring receiver is used. The specified frequency range isslowly scanned. During the scanning, it might be necessary toswitch off the device under test to determine whether the re-gistered interference on specific frequencies originates fromthe device or from the ambient. The ambient signals also preventthe use of a spectrum analyzer. A spectrum analyzer can withgreat advantage be used in a shielded room. A survey of the totalnoise spectrum will be given in one sweep. Information about thedominating frequencies for the interference will be given. Forpurpose of interference suppression, the spectrum analyzer isexcellent, as it displays the entire frequency range. However, itmust be remembered that the final measurements have to be carriedout on the outdoor measuring site.

(188.) According to VDE, measurements of the radiation in the frequencyrange 10 kHz to 30 MHz are also required. The ambient noise inthis frequency range is usually too large to allow measurementsoutside a shielded room.

45

3.3 Suppliers and economic considerations

(189) In this section some of the possible suppliers are listed. Theprices for the listed instruments are those valid today (primo1986) in Denmark. Some of the prices can vary slightly at thedifferent markets of the world. The prices for those facilities,which have to be constructed by local workers are estimatedfigures.

(190) Manufacturers: Rohde & Schwarz (R&S)

Schwarzbeck/Chase (Schw/Cha)(Though two companies, they are very closerelated).

Eaton (Ea)(The RFI products from this company have pre-viously been sold under brand names such as"Singer-Stoddard" and "Ailtech").

Electro-Metrics*

Hewlett Packard (HP)

Siemens

I suppliers of shielded roomsBelling & LeeRay Proof

* The company is a supplier of the same type of RFI equipment as the com-pany EATON. Their products are not included in this report.

3.3.1 Facilities

Open area test site:

(191) It is not possible at the moment to give any estimation of theprice, as the price level for the local working force is notknown.

Shielded rooa:

(192) A turn key room of an approx. size of 1=8 m, w = 5 m , h = 2.5 mUS$ 40,000

46

(193) Instead of a turn key room, local workers can make the construc-tion. If this solution is chosen, it is necessary to buy the doorincluding door-casing from one of the suppliers of shieldedrooms. The honeycombs for the ventilation and the mains filteralso have to be delivered from the professional suppliers.

Door

Filter

: US$ 6,000

: US$ 4,000

Honeycombs (6 pcs. of 325 mm x 325 mm) : US$ 3,000

3.3.2 EMI meters

Test receivers:

Manufacturer

R&SR&SR&SR&SEatonEatonEatonSchwarzbeckSchwarzbeckSchwarzbeckSchwarzbeckChaseChaseChaseChase

Type No.

ESH2ESH3ESVESVPNM 17/27ANM 37/57ACCA- 7LSME 1530FSME 1515FMLK 1518VUME 1520ALFR 1000HFR 2000UHR 4001UHR 4000

Frequency range

9 kHz- 30 MHz9 kHz- 30 MHz20 MHz- 1 GHz20 MHz-1.3 GHz10 kHz- 32 MHz30 MHz- 1 GHZ10 kHz- 1 GH210 kHz-150 kHz80 kHz- 30 MHz9 kHz- 30 MHz25 MHz-1000 MHz9 kHz-150 MHz

150 kHz- 30 MHz25 MHZ-300 MHz25 MHz-1000 MHZ

PriceUS$

25,00036,00032,00050,00031,00033,0008,0009,00011,00021,50022,00010,00013,00036,00045,000

Comments

Manual operatedAutomaticManual operatedAutomaticManualManualC1SPR adaptorManualManualManualManualManualManualAutomaticAutomatic

Spectrum analyzers:

Manufacturer

HP

HP

HPHPHP

Type No.

8567A

8566B

853A/8558B85685A85650A

Frequency range

up to 1.5 GHz

up to 22 GHz

up to 1.5 GHzup to 1.5 GHz

PriceUS$

27,000

55/000

13,00020,0009,000

Comments

EMI softwareoptional

EMI softwareoptional

EconomyPreselectorCISPR adaptor

47

3.3.3 Accessories

Product

Artificialmains network

Artificialmains network

Artificialmains network

Artificialmains network

Artif fcalmains network

Disconitnuousinterferenceanalyzer

Absorbingclamp

Broadbanddipole*

Log-periodicantenna*

Loop antenna*

VHP dipole

UHF dipole

Broadbandantenna

Broadbandantenna

Tripod for theloop antenna

Antenna mast

Antenna mast

Turn table

Manufac-turer

R&S

Schwa .

Schwa.

Chase

Chase

Chase

R&S

R&S

R&S

R&S

Schwa.

Schwa.

Schwa .

Schwa.

R&SChase

R&S

HP/Emco

HP/Enco

Type No.

ESH2-Z5

NSLK 8128

NLSK 8126

HH 2053

m 2050

DIA 1512

MOS 21

HVF-Z1

HL 023A1

HFH2-Z2

VHA 9103

UHA 9105

BBA 9106

UHALP 9107

HFU-ZTP1

HFU-Z

- —

Priceus$

5,000

5,000

3,600

3,600

2,200

20,000

3,000

1,500

3,000

3,800

800

800

300

1,100

1,5001,500

5,000

20,000

15,000

Comments

4x25A (50A)

4x32A (50A)

ax16A

4x16A

2X15A

Requires a testreceiver

25-80 MHz

80-1300 MHz

9 kHz-30 MHz

Adjustable30-300 MHz

Adjustable300-1000 MHz

30-300 MHz (requiresVHA 9103}

300-1000 MHz

Transportablemanually elevation

Automaticallyelevation

Automaticallyrotation

* These antennae are also available from EMCO for approx. the same price.

48

3.3.4 Software and peripherals

Product

EM! software

EMI softwareControl lerControl ler1 HbytememoryPlotter

Plotter

PlotterPrinter

Manufac-turer

HP

R&SR&SHPHPHP

HP

R&S

Type No.

85864B

ESVP K2PCA59816S98257A7550

7*470

DOP

PriceUS$

3,000

1,80011,0005,6001,5003,850

1,500

2,5002,000

Comments

Requires a 1 Mbytememory

8 pens + papercassette2 pens ideal for853A/8558B

3.3,5 Complete automatically operated test systems

(194) Both Rohde & Schwarz, Chase and Hewlett Packard offer completeautomatically operated test system. The instrumentation is formedby a number of the units listed. The approximate price for thefrequency range 9 kHz - 1 GHz:

Complete test system: approx. US$ 100,000

(Excl. turntable and antenna mast)

3.4 Calibration and maintenance

(195) Even though many modern EMI meters have built-in calibration fa-cilities, which automatically check the meter before each meas-urement, it is necessary to have a regulary calibration routinewith traceability to primary standards if the test results haveto be approved by the authorities.

(196) For calibration very complex and accurate equipment is necessary.Therefore, such measurements can only be carried out at very fewlaboratories. Hong Kong Government standards and calibration hasthe capability to do this. Agents for manufacturers of EMI metersoperate in many countries and some of these have the capabilityto carry out routine check and smaller repairs of complexmeasuring equipment. In Hong Kong for example Rohde & Schwarzhas the necessary facilities for this. However, if the measuringequipment is exposed to more serious damages or faults, the re-pair can often only take place at the manufacturer's laboratory,due to the very complex nature of these instruments. The moreautomatic and thereby complex the instrumentation is, the moretime must be foreseen for maintenance. At least 3-4 weeks an-nually, the equipment cannot be used due to calibration and main-tenance. Therefore, it is necessary to have more than one sample

49

of equipment in order to serve the industry properly. However,the additional instrumentation also increases the capacity ofthe test house.

3.5 Me©d for recognition of test results

(197) The manufacturers could save large amounts of money if the typeapproval tests carried out by one test house or authority wasrecognized by other authorities all over the world. Unfortunate-ly, this is not the case. No authorities issue a general accep-tance to a test house to have their test results recognized.There does not exist any qualification exam to pass, which per-mits a test house to issue type approval marks. However, manyauthorities will accept technical reports from test houses as abasis for a type approval if adequate information about the technical level of the test house is given. At the same time manyproducts need no type approval. A verification or a certificationbased upon the measuring results from a foreign test house willbe sufficient.

(198) The application procedures differ from country to country andthey depend on the product category. Below three administrativeprocedures will be discussed briefly. These are:

FCC (USA)

EEC (European Economic Communities)

National European Authorities (procedures, which arenot harmonized within EEC).

FCC

(199) The FCC operates with four different application procedures:

Verification, where the manufacturers merely assure that theequipment complies with the appropriate technical standards. Theother procedures are: Type approval, Type acceptance and Certifi-cation, which all need an authorization from the FCC. An applica-tion for an equipment authorization shall be filed on a form pre-scribed by the Commission. Each of them shall be accompanied byall the information required in the relevant part of the rulesand regulations. The technical test data submitted with the ap-plication shall be signed by the person who performed or super-vised the tests. The Commission may require this person to submita statement showing that he is qualified to perform or supervisethe required measurements. Each laboratory making measurements tobe filed with an application at the FCC shall submit a descrip-tion of their measurement facilities to the Commission. The de-scription shall include the following information:

1) Location of the test site.

2) Physical description of the test site accompaniedby photographs.

3) Drawing showing the dimensions of the site, the physi-cal layout of supporting structures, and all structureswithin 5 times the distance between the measuring setand the device being measured.

4) Description of supporting structures used to supportthe device under test.

5) List of measuring equipment used.

6) Information concerning the calibration of the measuringequipment i.e. when the equipment was last calibratedand frequency of calibration.

7) A statement indicating whether this facility is avail-able to do measurement work for others on contractbasis.

(200) The information shall be kept current at all times. At leastevery 3 years the organization filing the data shall advice thatthe data on file is current.

(201) The open field test site shall be calibrated in accordance withFCC bulletin QST55, August 1982, which specifies the siteattenuation.

(202) Applications for equipment authorizations shall be mailed to FCCat the following address:

Chief, Authorization & Standards DivisionFCCP.O. Box 429Columbia, Maryland 21045USA(Phone: + 301 - 725 - 1585)

(203) Grants can be given to foreign manufacturers as well as importersin the USA.

EEC (European Economic Communities)

(204) In order to facilitate the exchange of goods within the EuopeanCommon market, harmonization of national rules and regulations isrecommended. The harmonization is governed through directivesfrom the Communities, These directives shall be incorporated inthe national legislation. Up to now only a few regulations havebeen harmonized, but the tendency is that more and more har-monization will take place and the harmonization work will bespeeded up.

(205) If a Product is subjected to an EEC directive, a type approval isnot necessary. The product can be marketed by using a manufac-turer declaration stating that it complies with the relevantdirective and given by a person who is a citizen of the countryin question. This person does not need to possess measuring faci-lities or have a technical education. However, in case of inter-ference problems caused by the product he will be held respon-sible by the authorities.

(206) The declaration can be based on measurements carried out by localtest facilities in HK. The statement shall be given in the manual,the guarantee certificate or be placed conspicuously on the pro-ducts. The statement shall be given in the national language.Directives in English language can be ordered from the UnitedKingdom:

H.M. Stationery OfficeP.O. Box 569London SE1 9NH(Phone: + 1 - 9286977 ext 365)

national Euopean Authorities

(20?) Products, which are not subject to any EEC directives, have to beauthorized in each country. This especially concerns radio trans-ceivers like walkie-talkies. Normally, the authorities do notaccept any technical measurements submitted by the manufacturers.The measurements have to take place at a laboratory controlled bythe Postal Authorities. The lack of harmonization is not onlyconcentrated to the administrative procedures, also the technicalspecifications differ from country to country* Furthermore, thespecifications are subject to changes, which makes it difficultto ensure that a certain specification is up to date. Mostly,individual manufacturers cannot achieve a subscription for thiskind of technical standards.

(208) However, if local facilities were available in HK this organiza-tion -would be able to assist the manufacturers with some of themeasurements, especially the spurious emissions from the cabinet,which require an open air test site. After some time, when alocal organization has proved its capability to perform this typeof measurements, it might facilitate the procedure to have awalkie-talkie accepted.

(209) Furthermore, the organization could on request provide the manu-factures with the relevant standard and application forms.

(210) In most countries applications for authorizations have to be sub-mitted to the General Directorate of Posts and Telecommunications.Information about rules and regulations can also be given bythese organizations. A list of addresses for a number of foreignauthorities is given in APPENDIX 2.

52

3.5.1 Accreditation schemes

(211) Technical testing is carried out at many laboratories all overthe world. The test reports issued by these laboratories are usedas documentation to demonstrate that a certain product meets therequired specifications. The users of the test reports may by do-mestic or foreign contracting parties, or public auhorities, whomthe contracting parties approach with respect to the test report.The basic interest of the users is that the testing is carriedout with adequate security with regard to technical testing, andthat performance of the testing is documented.

(212) To cover these demands some countries have introduced accredita-tion shemes. Accreditation is a formal recognition of a testinglaboratory to carry out tests in accordance with clearly and un-ambiguously defined methods, shown in advance by testing or useover a certain time to be repeatable and reproducible. Such me-thods are i.e. described in standards, in public directives orother similar documents. However, testing technique and technicaldevelopment often takes place at such a rate that the normal pro-cedures for obtaining consensus on new methods do not satisfy thedemand to have new tests carried out* Therefore, laboratoriesmust often make decisions about the application of methods whichare described, but not yet finally published; If such methods canbe evaluated in a sufficiently qualified manner as being moregenerally recognized - and used - they can often justifiably beconsidered as having the same status as the official methods.

(213) Accreditations are awarded as a result of successful laboratoryassessment and are followed by appropriate monitoring* Moreover,the laboratory must have an organizational structure, including asystem for quality assurance, enabling it to maintain the levelsdetermined for performing the activities in the laboratory. Thebasis criteria for facilities as well as personnel of an accre-dited laboratory is described in ISO Guide 25 "General Require-ments for the Technical Competence of Testing Laboratories".

(214) A national accreditation scheme was set up in Denmark in August1973. Elektronikcentralen has been operating successfully underthis scheme since 1976. The oldest accreditation scheme is foundin Australia, where it has been operating since 1947. The demandsfor testing and official certificates are increasing due to thefact that the products become more and more complicated. The con-sumers want to be sure that a product meets the specified re-quirements. In order to avoid the same test to be carried out ina number of countries, and to save money for the individual con-sumer, the interest in authorized laboratories is increasing. In1977 the first international conference on mutual recognition ofnational accredited laboratories was held in Copenhagen. Afterthis conference the International Laboratory Accreditation Com-mittee (ILAC)was founded. The objectives of this organizationare to work for international recognition of technical reportsfrom accredited laboratories. Unfortunately, ILAC has up to now

53

not succeeded in a worldwide recognized accreditationscheme. But due to the fact that more and more testing ofproducts is needed many national testing boards have madebilateral agreements in specific areas. Moreover, even ifno formal agreement exists a test report from an accreditedlaboratory will often reduce the number of tests in theother countries.

3.5.2 International standardization organizations

(215) Participation in international standardization work willgive information about the trends in the internationallegislation and the personal contacts with participantsfrom other countries will often be helpful in order tc havethe technical reports recognized* The two most importantinternational standardization organizations are ISO andIEC.

c sc sc

ommute*S«b»€ommj(trt

f Commit!**Coflt«iit«t

FIG. 10 The organizational structure of the IEC.

54

APPENDIX 1

Definitions of terms

This appendix gives the definitions of the terms used in the EMCtechnology. Many of the definitions have not been used in thisreport, they are only given as information. Before the terms aregiven in alphabetical order some basic terms are presented.Further, two terms "RFI test house" and "RFI service centre11

which have been frequently used throughout the report shall beexplained.

DEFINITIONS

RFI test house

An organization which has all the necessary equipment and exper-tise to carry out EMC measurements according to various stan-dards. They are capable of making redesign or interferencesuppression of the test object if it does not meet the requiredlimits.

RFI service centre

An organization with the same capabilities as for the "RFI testhouse11. But their services are extended with consultative taskssuch as information about mandatory standards in variouscountries, interpretations of standards, approval procedures,setting up test specification without doing any tests, andgeneral information about EMC matters.

EMC

ELECTROMAGNETIC COMPATIBILITY - the meaning of which is:

The capability of a device to function satisfactorily in itselectromagnetic environment without introducing intolerabledisturbances to that environment or to other devices therein.

1FI

Radio frequency interference - the degradation of the receptionof a wanted signal caused by radio frequency disturbances.

Electromagnetic noise

An electromagnetic phenomenon uncorrelated with any signal andwhich is usually impulsive and random, but may be of a periodicnature.

Note: In some countries, periodic phenomena are not encompassedby the term "noise".

Electromagnetic disturbance

Electromagnetic noise or an unwanted signal which might besuperimposed on an electrical signal or electrical quantityand which may produce performance degradation.

Unwanted signal

A signal that may impair the reception of a wanted signal.

Electromagnetic interference

Impairment of the functioning of a device, equipment or systemcaused by an electromagnetic disturbance.

The totality of electromagnetic sources makes out the:

Electromagnetic environment

The totality of electric and magnetic field strengths (or powerflux densities) voltages and currents, whether intentionally orunintentionally generated existing at a given locaiton.

The EM-environment includes:

Natural sourcesMan-made noise sources

Natural sources

EM signals not produced by man. May be divided into:

Cosmic noiseAtmospherics

Man-made noise

Noise generated by machines or other man-made devices.

57

ALPHABETIC LIST OF TERMS

Absorbing clamp (HDS-clamp)

A measuring device (defined by CISPR), moveable along the mainslead of an energized appliance intended to assess the level ofinterference power which is produced by this appliance.

Artificial aains network

American: Line impedance stabilizationNetwork LISN

A network inserted in the supply mains lead of the apparatus tobe tested which provides, at radio frequencies, a specified loadimpedance for the measurement of interference voltages and isola-tes the apparatus from the supply mains at radio frequencies.

Two main types exist:

V-networkDelta network

Asymmetrical (covnon node) interference voltage

Interference voltage (or the vector mean of the voltage)appearing between a conductor, a set of conductors (cable) or anapparatus and reference ground.(See further: Terminal interference voltage).

Average detector

A detector whose output voltage is the average of the envelope ofan applied signal.

58

BROADBAND NOISE

TIME DOMAIN

FREQUENCY DOMAIN

EUEKTRONIKCENTRAtCM

Broadband signal

A signal having a spectral energy distribution sufficiently uni-form and continuous, so that the response of the measuringapparatus or receiver does not vary significantly when tuned overa range of frequencies several times the receiver bandwidth.

Burst

A succession of short pulses, typically generated when an induc-tive load is switched off.

Capacitive coupling

Coupling of a (noise) signal from one circuit to another by anelectrical near-field.

Click (defined by CISPR)

A pulse with a duration shorter than 200 ms and which isseparated from the following disturbance by an interval of atleast 200 ms. A click may contain a number of pulses.

Coraoii mode voltage

See: Asymmetrical voltage.

Conducted interference

Electromagnetic interference which is propagated along a conduc-tor, a water pipe, structural steel or other metal structures.

Conductive coupling

Coupling of a (noise) signal from one circuit to another by animpedance common to both circuits.(See further: Transfer impedance).

Continuous noise

Electromagnetic disturbance (noise), the effect of which is notresolvable into a succession of discrete pulses in the normaloperation of the particular system concerned and whose averageamplitude does not vary significantly with time.

According to CISPR impulsive noise with a duration of more than200 ms.

Coupling factor

The ratio of voltage (or current) appearing at a specified loca-tion of a given circuit to the corresponding voltage (or current)at a specified location in the originating circuit.

Culprit circuit

Circuit which causes interference to another circuit or equipment.

Delta network

An artificial mains network used for measurements enabling thesymmetrical and asymmetrical disturbance voltages of a singlephase circuit to be measured seperately.

Detector functions

Three main types of detectors are referred to:

Quasi-peak detectorAverage detectorRMS detector

Differential mode (Syaaetrical) voltage

The voltage between any two of a specified set of activeconductors.

60

Discontinuous interference

Electromagnetic disturbance (noise) occurring during some periods(bursts) alternated with noise-free intervals.

Mote: Discontinuous noise of specified duration and repetitionperiods is categorized as clicks.

Electric field

Near-field, where the wave impedance Zy is higher than for afar-field

Z = -i-TJL > 377 flW I Hi

61

ELECTROMAGNETIC FIELD

DIRECTION OPPROPAGATION

IMPEDANCE OF FIELDIII

FAR FIELD : Z « t 2 0 « « 3 7 7 o

NEAR FIELDS i

ELECTRIC FIELD : Z>377o

HAGNETIC FIELD : Z<3T7Q

fLEKT«ONIKCENTRALEN

Electro»agpnetic field

Far-field where the eletrical component E and the magnetic com-ponent H are perpendicular to each other and where the fieldimpedance Zy is constant

= 120 IT = 377

Enission

Emanation of electromagnetic energy from a source by radion orconduction or both.

62

Conducted emission

Electromagnetic energy which is propagated along a conductor.

Radiated emission

Emission which may be coupled to a susceptible device byradiation (including induction).

External immunity

Capability of a device, equipment or system to resist disturban-ces appearing at other than its normal input terminals or antenna.

Electrostatic discharge (ESD)

• A' transfer of electrostatic charge between bodies of differentelectrostatic potential by direct contact.

Immunity

The capability of a device, equipment or system enabling it toresist an electromagnetic disturbance.Is the complementary term of susceptibility,

Impulsive noise (disturbance)

Electromagnetic disturbance (noise), the effect of which isresolvable into a succession of discrete pulses in the normaloperation of the particular system concerned.

Inductive coupling

Coupling of a (noise) signal from one circuit to another by amagnetic near-field.

Insertion loss

The ratio of the voltages (or currents) appearing immediatelybeyond the point of insertion of a component or filter unit in agiven system, before and after the insertion.

Internal immunity

Capability of a device, equipment or system to resist disturban-ces appearing at its normal input terminals or antenna.

Inter-system interference

Electromagnetic interference in one system due to a disturbanceproduced by another system.

Intra-systea interference

Electromagnetic interference occurring in a given system due to adisturbance produced within the same system.

ISM (Industrial, scientific, »edical) equipment

Equipment for non-communication industrial, scientific, medical,household, or similar applications in which radio frequency energy,is intentionally generated or used in order to treat materials.

Line impedance stabilization network LISM

American term for artificial mains network.

Magnetic field

Near-field where the wave impedance Zy is lower than in thefar-field

377Z =_!_=.w IE

NARROWBAND NOISE

27.12 54,24 81,36 108.48FREQUENCY DOMAIN

I ^

eiEKTftONIKCCMTRAUM

Narrowband signal

Signal which has a bandwidth being small compared to the band-width of the registering apparatus (measuring receiver).

64

Near-field

State of an electromagnetic field in short distance from the ra-diating antenna where the far-field conditions have not yet oc-curred.

Peak detector

A detector, the output voltage of which is the peak value of anapplied signal.

Quasi-peak detector

A detector having specified electrical time constants, which whenregularly repeated pulses of constant amplitude are applied toit, delivers an output voltage which is a fraction increasing to-wards unity as the pulse repetition rate is increased,

Radiation

Emission, by a mechanism other than conduction, of a wanted sig-nal or an electromagnetic disturbance.

Radio environment

The combined effect at any given location of the emission createdby normally operating authorized transmitters. It has the dimen-sion of field strength and varies with frequency.

Root-nean-square (RMS) detector

A detector, the output voltage of which is the RMS value of anapplied signal.

Sag (dip)

English term for a short drop or decrease of the power voltage.

Duration : A fraction of and up to some tens of periods.

Spike

English term for a short pulse superimposed on the supply voltageor signal leads.

Duration : Less than 1 ms.Amplitude: Up to some kV.

Stripline

A terminated transmission line consisting of two parallel platesbetween which a transverse electromagnetic field is set up fortesting purposes.

65

Surge

English term for a pulse longer than a spike.

Duration: A half period an dup to a few periods.

Susceptibility

The incapability of a device, equipment or system to resist anelectromagnetic disturbance.

Notes: (1) Susceptibility is a lack of immunity.(2) The larger the value of the immunity level, the higher

higher is the immunity. Contrarily, the lower thelevel of the susceptibility the higher is the suscep-tibility.

Symmetrical (noise) voltage

See: Differential mode voltage.

TEM-cell

An enclosed system in which the electromagnetic wave is propa-gated in the transversal electromagnetic (TEM) mode to produce aspecified ambient field for measuring purposes.

Note: The electromagnetic field in such a device simulates afree space field.

66

INTERFERENCE VOLTAGES AT THETERMINALS OF AN APPARATUS

Vo

VF V"D

*WWXMZ^^

\r.

JLt-

Vc

Ve

EtEKTRONlKCENTfULEN

Terainal voltages

Voltages from leads (or terminals of an apparatus) to referenceground or between leads.

The figure shows examples of -terminal voltages.

VF, VQ = V-terminal voltages

Vj) = Differential mode voltage

VQ = Common mode voltage

67

TRANSFER IMPEDANCE, DEFINITION

ELECTROMAGNETICENVIRONMENT

ItFIELD-INDUCED CURRENTON OUTER SURFACE

PROTECTED AREA

U,

VOLTAGE COUPLED THROUGHTO INNER SURFACE

BORDER

z -ZT-|E

ELEKTRONIKCENTRALEN

Transfer impedance Zt

The ratio between the voltage Uj coupled into a screened systemand the generating current Ig on the screen.

V-network

An artificial mains network used for measurements enabling theinterference voltages between each wire and earth to be measuredseparately.

Note: The V-network may be designed for application to networksof any number of wires.

Victim

Circuit or equipment which is exposed to an interference signal.

66

APPENDIX 2

Addresses of foreign teleadministrations

AUSTRALIAThe SecretaryDepartment of CommunicationsP.O. Box 34Belconnen A . C . I . 2616 (Australia)

BELGIUMRegie des telegraphes et des telephonesrue des palais, 42B-1Q30 Bruxelles

CANADAThe Director GeneralInternational Relations BranchDepartment of CommunicationsJournal North Building300, Slater StreetOTTAWA, Ontario K1A OC8 (Canada)

DENMARKPost- og TelegrafvaasnetTELEINSPEKTIONENIslandsbrygge 81DK-2300 Copenhagen S

FINLANDGeneral Directorate of Postsand TelecommunicationsP.O. Box 528SF-00101 Helsinki 10

FRANCEDirection generale des telecommunicationsDirection des Affaires industrielleset internationales (DAII)Service des affaires internationales (SAI)38-40, rue du General-LeclercF-92131 Issy.les Moulineaux

GREECEMinistere des communicationsDirection generale des postes ett.e 1 ecommunica t ions49, avenue SyngrouATHINAI (Grece)

HOLLANDDirection generale des postes,des telegraphes et des telephonesKortenaerkade 122518 AX La Haye (Pays-Bas)

70

SWEDENHeadquarters of the SwedishTelecommunications AdministrationS-123 86 FARSTA

USADirectorOffice of International CommunicationsPolicy (EB/TD)Department of stateWashington, B.C. 20520 (United States)

GERMANY (FRG)Bundesministerium fur das Post undFernmeldewesenAdenauerallee, 81D-5300 Bonn

AUSTRIADirection generale des postes etdes telegraphesPostgasse 8A-1011 Wien

JUGOSLAVIACommunaute des postes, telegrapheset telephones yougoslavesPalmoticeva, 211000 Beograd (Yougoslavia)

HUNGARYAdministration centrale des postes ettelecommunications de HongrieBudapestRep. pop. hongroise1540

TJEKKOSLOVAKIAFederal Ministry of Posts andTelecommunicationsInternational DivisionOlsanska 5CS:- 125 02 Praha 3

IRELANDDepartment of Posts and TelegraphsCommercial BranchInternational Division4th level, Ardilaun CentreSt.' Stephen's Green, Dublin 2 Ireland

71

ICELANDThe Director General of Posts andTelecommunicationsP.O. Box 270121 Reykjavik (Iceland)

ITALYMinistreo Poste e TelecomraunicazioniDirezione GeneraleUfficio Relazioni InternazionaliViale America1-00100 Roma-Eur

LUXEMBURGDirection des poster etTelecommunicationsL-202Q Luxembourg

NORWAYNorwegian TelecommunicationsAdministrationPostboks 6701, St. Olavs plassN-Oslo 1

SWITZERLANDDirection generale de 1'Entreprisedes postes, telephones et telegraphesCH-3030 Berne

SPAINMinisterio de Transportes, Turismoy CommunicacionesJunta Nacional de Telecommunicaciones(Gabinete de Ordenacion de lasTelecommunicaciones)Calle.de Alcala, 54Madrid 13 (Espana)

UNITED KINGDOM (U.K.)The Under SecretaryPosts and Telecommunications DivisionDepartment of IndustryAshdown House123, Victoria StreetLondon SW1E 6RB (United Kingdom)

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