1、BRITISH STANDARD BS EN 60835-2-9:1997 BS 7573-2.9: 1997 IEC 835-2-9: 1995 Methods of measurement for equipment used in digital microwave radio transmission systems Part 2: Measurements on terrestrial radio-relay systems Section 2.9 Service channels The European Standard EN 60835-2-9:1995 has the sta
2、tus of a British Standard ICS 33.060.30BSEN60835-2-9:1997 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 January 1997 BSI 11-1998 The following BSI references r
3、elate to the work on this standard: Committee reference EPL/12/5 Draft for comment 91/29838 DC ISBN 0 580 26392 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EPL/12, Radio communication, to Subcommittee EPL/12/5, Radi
4、o communication systems, upon which the following bodies were represented: British Broadcasting Corporation British Radio and Electronic Equipment Manufacturers Association British Telecommunications plc ERA Technology Ltd. Institution of Electrical Engineers Radio, Electrical and Television Retaile
5、rs Association Radiocommunications Agency Amendments issued since publication Amd. No. Date CommentsBSEN60835-2-9:1997 BSI 11-1998 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 60835-2-9 3 List of references Inside back coverBSEN60835-2-9:1997 i
6、i BSI 11-1998 National foreword This British Standard has been prepared by Subcommittee EPL/12/5 and is the English language version of EN 60835-2-9:1995 Methods of measurement for equipment used in digital microwave radio transmission systems Part2:Measurements on terrestrial radio-relay systems Se
7、ction 9: Service channels, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 835-2-9:1995, published by the International Electrotechnical Commission (IEC). BS EN 60835 is published in three Parts. The other Parts are: Part 1: Measurements c
8、ommon to terrestrial radio-relay systems and satellite earth stations. Part 3: Measurements on satellite earth stations. Some of the many Sections of the three Parts have appeared under the number BS 7573, of the same generic title. This Section of BS EN 60835 deals with measurements pertaining to t
9、he service channels used in digital microwave radio-relay systems. Cross-references Publication referred to Corresponding British Standard BS EN 60835 Methods of measurement for equipment used in digital microwave radio transmission systems BS EN 60835-1 Measurements common to terrestrial radio-rela
10、y systems and satellite earth stations EN 60835-1-2:1993 BS EN 60835-1-2:1995 Basic characteristics (IEC 835-1-2:1992) EN 60835-1-3:1995 BS EN 60835-1-3:1997 1)Transmission characteristics (IEC 835-1-3:1992) EN 60835-1-4:1995 BS EN 60835-1-4:1997 1)Transmission performance (IEC 835-1-4:1992) EN 6083
11、5-2-4:1995 BS EN 60835-2 Measurements on terrestrial radio-relay (IEC 835-2-4:1993) systems BS EN 60835-2-4:1997 1)Transmitter/receiver including modulator/demodulator A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsibl
12、e for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2 to 14, an inside back cover and a back cover. This st
13、andard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover. 1) In preparationEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60835-2-9 December 1995 ICS 33.060.30 Descriptors: Telecommunications,
14、radiocommunications, communication equipment, digital technics, radio-relay systems, microwave frequencies, transmission channels, measurements English version Methods of measurement for equipment used in digital microwave radio transmission systems Part 2: Measurements on terrestrial radio-relay sy
15、stems Section 9: Service channels (IEC 835-2-9:1995) Mthodes de mesure applicables au matriel utilis pour les systmes de transmission numrique en hyperfrquence Partie2:Mesuresapplicables aux faisceaux hertziens terrestres Section 9: Voies de service (CEI 835-2-9:1995) Meverfahren fr Gerte in digital
16、en Mikrowellen Funkbertragungssystemen Teil 2: Messungen an terrestrischen Richtfunksystemen Hauptabschnitt 9: Dienstkanle (IEC 835-2-9:1995) This European Standard was approved by CENELEC on 1995-11-28. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate th
17、e conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exist
18、s in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electr
19、otechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Elec
20、trotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1995 Copyright reserved to CENELEC members Ref. No. EN 60835-3-6:1995 EEN60835-2-9:1995 BSI 11-1998 2 Foreword The text of document 12E/246/DIS, future edition 1 of IEC 835-2-9, pre
21、pared by SC 12E, Radio-relay and fixed satellite communication systems, of IECTC 12, Radiocommunications, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60835-2-9 on 1995-11-28. The following dates were fixed: Annexes designated “normative” are part of the body of t
22、he standard. Annexes designated “informative” are given for information only. In this standard, annex ZA is normative and annex A is informative. Annex ZA has been added by CENELEC. Contents Page 1 General 3 1.1 Scope 3 1.2 Normative references 3 2 Analogue interface of service channels transmitted
23、by analogue techniques 3 2.1 Return loss 3 2.2 Input deviation sensitivity 3 2.3 Output deviation sensitivity 4 2.4 Transmit-receive section parameters 4 3 Analogue interface of service channels transmitted by digital techniques 5 3.1 Return loss 5 3.2 Amplitude-frequency characteristic 5 3.3 PCM co
24、der overload point 5 3.4 Idle channel noise 6 3.5 Total distortion including quantizing distortion 6 4 Digital interface of service channels transmitted by digital techniques 6 4.1 Return loss, terminal balance ratio 6 4.2 Acceptability of the signal at the input of the transmit code converter 6 4.3
25、 Level and shape of the signal at the output of the receive code converter 7 4.4 Effect of jitter 7 Annex A (informative) Bibliography 13 Annex ZA (normative) Normative references to international publications with their corresponding European publications 14 Figure 1 Method of service channel trans
26、mission over a digital radio-relay system 8 Figure 2 Measurement of peak-to-peak deviation in case of sinusoidal modulation using a spectrum analyzer 9 Figure 3 Back-to-back connection of transmit-side and receive-side multiplex equipment 10 Figure 4 Test arrangement for measuring the signal-to-tota
27、l distortion ratio 11 Figure 5 Test arrangement for measuring the acceptability of the signal at the input of the transmit code converter 11 Figure 6 Test arrangement for measuring the level of the signal at the output of the receive code converter 12 latest date by which the EN has to be implemente
28、d at national level by publication of an identical national standard or by endorsement (dop) 1996-09-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 1996-09-01EN60835-2-9:1995 BSI 11-1998 3 1 General 1.1 Scope This section of IEC 835-2 deals with mea
29、surements pertaining to the service channels used in digital microwave radio-relay systems. In digital radio-relay systems, two basic methods are commonly used for the transmission of service channel signals (that is voice, supervisory and control signals) (see annex A, ref. 6). The first transmissi
30、on method uses analogue transmission techniques where the i.f. or r.f. carrier signal of the digital modulator is directly frequency-modulated by the analogue service channel signal, which is then recovered at the receive end by an f.m. demodulator (for example in the carrier recovery circuit of a c
31、oherent digital demodulator). In the second method of transmission, digital transmission is used and the service channel signal is transmitted in the form of separate bits inserted into the main bit stream by a multiplexer (possibly together with a bit stream carrying additional information). For di
32、gital transmission, the service channel signal may be either an analogue signal which is digitally encoded for bit insertion or a digital signal, in which case suitable code conversion is normally applied in order to convert the line code into a code suitable for the radio equipment. At the receive
33、end, a demultiplexer is used to recover the service channel bits and thus supply, after suitable decoding or code conversion, the service channel output signal. Normally, more than one service channel is transmitted. Sometimes an additional bit stream (for example alarm control signals for protectio
34、n switching and supervisory equipment) may also be transmitted. Suitable multiplexing and demultiplexing equipment is then used, such as frequency division multiplexing for analogue transmission, and time division multiplexing for digital transmission. The use of time division multiplexing also allo
35、ws the simultaneous digital transmission of analogue and digital service channel signals. Figure 1 shows the simultaneous application of all the above possible service channel transmission systems. However, in a given radio-relay link, only one or two of these systems is used at a time. 1.2 Normativ
36、e references The following normative documents contain provisions which, through reference in this text, constitute provisions of this section of IEC 835-2. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based
37、 on this section of IEC 835-2 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 835-1-2:1992, Methods of measurement for equipment us
38、ed in digital microwave radio transmission systems Part 1: Measurements common to terrestrial radio-relay systems and satellite earth stations Section 2: Basic characteristics. IEC 835-1-3:1992, Methods of measurement for equipment used in digital microwave radio transmission systems Part 1: Measure
39、ments common to terrestrial radio-relay systems and satellite earth stations Section 3: Transmission characteristics. IEC 835-1-4:1992, Methods of measurement for equipment used in digital microwave radio transmission systems Part 1: Measurements common to terrestrial radio-relay systems and satelli
40、te earth stations Section 4: Transmission performance. IEC 835-2-4:1993, Methods of measurement for equipment used in digital microwave radio transmission systems Part 2: Measurements on terrestrial radio-relay systems Section4:Transmitter/receiver including modulator/demodulator. 2 Analogue Interfa
41、ce of service channels transmitted by analogue techniques 2.1 Return loss See IEC 835-1-2. 2.2 Input deviation sensitivity 2.2.1 Definition The input deviation sensitivity, S m , of a frequency modulator, for a sinusoidal signal with a given frequency, is expressed as the ratio of the frequency devi
42、ation, Df, to the baseband voltage, V b , at the input of the service channel, i.e.: S m= Df / V bkHz/V V band Df are both expressed in either peak or r.m.s, values. The deviation sensitivity of the modulator is a function of the baseband frequency if a pre-emphasis network is applied.EN60835-2-9:19
43、95 4 BSI 11-1998 2.2.2 Method of measurement The service channel input port is driven by a sinusoidal signal with an input level and frequency producing the specified nominal deviation. The r.f. output port of the transmitter is connected, via a suitable r.f. attenuator, to a down converter which co
44、nverts the frequency of the r.f. output signal to the i.f. range, and a deviation meter is connected to the i.f. output of the down converter. The down converter and deviation meter are both commercially available items of equipment. The reading of the deviation meter is noted, and the deviation sen
45、sitivity is calculated as the ratio of the deviation to the input level. A simple alternative method can be applied if the modulation index is large enough, for example if Df is 70 kHz and modulation frequency is 1 kHz. On a spectrum analyzer with calibrated frequency axis, the f.m. spectrum around
46、the centre frequency produced by a sinusoidal drive signal is displayed using a measurement bandwidth around 1 % of the deviation to be measured. The peak-to-peak deviation can be read immediately as indicated in Figure 2. In case the deviation meter or spectrum analyzer is not able to measure prope
47、rly when the carrier is modulated by the main bit stream, it may be necessary to carry out the measurement in the absence of modulation. 2.2.3 Presentation of results Input signal level and frequency, together with the measured deviation and the calculated deviation sensitivity, are tabulated. 2.2.4
48、 Details to be specified The following items should be included, as required, in the detailed equipment specification: a) nominal input signal level and frequency; b) permitted deviation sensitivity range. 2.3 Output deviation sensitivity 2.3.1 Definition The output deviation sensitivity, S d , of a
49、 frequency demodulator for a sinusoidal signal with a given frequency is expressed as the ratio of the baseband voltage, V b , at the service channel output to the frequency deviation Df, i.e.: S d= V b/ Df V/kHz V b and Df are both expressed as either peak or r.m.s. values. The deviation sensitivity of the demodulator is a function of the baseband frequency if a de-emphasis network is applied. 2.3.2 Method of measurement The demodulator i.f. input port is disconnected from the receiver and driven by a signal genera
