1、BRITISH STANDARD Methods of measurement for equipment used in digital microwave radio transmission systems Part 1. Measurements common to terrestrial radio-relay systems and satellite earth stations Section 1.2 Basic characteristics The European Standard EN 60835-1-2 : 1993 together with its amendme
2、nt Al : 1995, has the status of a British Standard ICs 33.060.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN BS 7573 : Section 1.2 : 1993 IEC 835-1-2 : 1992 60835-1-2 : 1995 Incorpomting Amendment No. 1 to BS 7573 : Section 1.2 : 1993 (renumbers BS as 1995) and ArnWm
3、t No. 1 to 1995 BS EN 60835-1-2 : BS EN 60835-1 -2 : STD*BSI BS EN b0835-1-2-ENGL 1775 9 1b24bb9 Ob39523 Li47 BS EN 60836-1-2 : 1995 Issue 2, September 1997 Tliis British Standard, having ken prepared under the direction of the Electronic Equipment Standards Policy Cominittee, was published tinder t
4、he authority of the Standards hard and coiiies into effect on 1.5 April 1993 O BSI 1997 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Electronic Equipinent Standards Policy Coinmittee (EEL/-) to Technical Cornmit,t.ee EELBS, upon which
5、 the following bodies were represented: British Broadcasting Corporation British Radio and Electronic Eqiiipiiieiit Maiiufactureix Association British klecorninunications plc Institution of Electrical Engineers Radio, Electrical and Television Retailers Association Radiocorninunications Agency The f
6、ollowing body was also represented in the drafting of the standard, I through subcommittees and panels: ERA Technology Ltd. The following BSI references relate to the work on this Standard: Coinmittee reference EELl25 Ilrafts for comment 89 24855 Dc !?0/3:W“ I“ ISBN O 580 21TJ2 9 Amendments issued s
7、ince publication Renuiiibeis BS as BS EN 60835-1-2 : 1995 STD-BSI BS EN b0835-1-2-ENGL 1775 = LbZVbbS Ob37524 383 = Issue 1, September 1997 BS EN 60835-1-2 : 1995 Issue 3 2 1 blank 2 2 2 2 Original blank original original 1 1 1 Summary of pages The following table identifies the current issue of eac
8、h page. Issue 1 indicates that a page has been introduced for the frst time by amendment. Subsequent issue numbers indicate an updated page. Vertical sidelining on replacement pages indicates the most recent changes (amendment, addition, deletion). Page lld 1 le 1 If 1 1g llh 12 13 14 14a 14b 15 16
9、Inside back cover Back cover Page Front cover Inside front cover a b i EN front cover iib iv 1 to 10 11 1 la 1 lb 1 IC 11 . 111 Change of identifier Issue 1 1 1 1 1 original original original 1 1 original blank blank 2 Wherever BS 7573 : Section 1.2 : 1993 appears in this standard, it should be read
10、 as BS EN 60835-1-2 : 1995. * vi * O BSI 1997 a STD-BSI BS EN b0835-1-2-ENGL 1775 Lb24bb7 Ob37525 2LT W Issue 2, September 1997 BS EN 60835-1-2 : 1995 Contents page Committees responsible Wide front cover National foreword ii Foreword iib introduction Method 1 Scope 2 Carrier frequency 3 spectrum ii
11、i 1 1 2 4 Impedance (admittance) 5 6 Level (volhgelpower level, gain) 8 I 6 Noise temperature and noise figure 1 la A (informative) Bibliography 15 Annex Figures 1 Arrangement for measuring fkequency 12 2 Arrangement for spectrum measurement 12 3 mical arrangement for measuring intermodulation produ
12、cts 13 4 13 6 14 6 mical arrangement for measuring insertion gain or loss 14 7 8 9 I I 10 D NORME EUROP- EUROP- Nom 1995 lb2Libb9 Ob39527 O92 EN 60835-1-2 August 1993 + Al March 1995 UDC 621.396.6 : 629.783 : 621.317.08 Descriptors: Radiocommunications, telecommunications, satellite broadcasting, co
13、mmunication equipment, earth stations, radio-relay systems, microwave frequencies, tests, characteristics, measurements English version Methods of measurement for equipment used in digital microwave radio transmission systems Part 1: Measurements common to terrestrial radierelay systems and satellit
14、e earth stations Section 2: Basic characteristics (includes amendment Al : 1995) (IEC 8351-2 : 1992 + Al 1995) Mthodes de mesure applicables au matriel utilis pour les systmes de transmission numrique en hyperfi-quence Partie 1: Mesures communes aux faisceaux hertziens terrestres et aux stations ter
15、riennes de tlcommunications par satelJite (inclut lamendement Al : 1995) Meverfhen fr Gerte in digitalen Mikrowellen-FunkUbertragungssystemen Teil 1: Messungen an terrestrischen Richtfunksystemen und Satelliten-Erdfunkstellen Hauptabschnitt 2: Grundlegende Eigenschaften (enthlt nderung Al : 1995) Se
16、ction 2: Caractristiques de base (lEC 8351-2 : 1992 + Al : 1995) (CE1 8351-2 : 1992 +Al : 1995) This European Standard was approved by CENELEC on 1993-07-06. CENELEC members are bound to comply with the CENKENELEC internal Regulations which stipulate the conditions for giving this European Standard
17、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 exists in three official versions (English, French,
18、German). A version in any other language made by transiation under the responsibility of a CENELEC member into its own language and notified to the Centrai Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denm
19、ark, 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 Electrotechnique Europisches Komitee fr Elektrotech
20、nische Normung Central Secretariat: rue de Stassart 36, B-1060 Brussels O 1993 Copynght reserved to CENELEC members Ref. No. EN 608351-2 : 1993 + Al : 1995 E STDeBSI BS EN b0835-L-Z-ENGL 1995 W LbZYbbS Ob39528 T27 EN 60836-1-2 : 1993 hue 2, September 1997 Foreword The CENELEC questionnaire procedure
21、, perormed for finding out whether or not the International Standard IEC 8351-2 : 1992 could be accepted without tem changes, has shown that no common modifications where necessary for the acceptance as a European Standard. The reference document was submitted to the CENELEC members for formal vote
22、and was approved by CENELEC as EN 608351-2 on 6 July 1993. The following dates were fured - latest date of publication of an identical national standard (dop) 19940801 atest date of withdrawal of conflicting national standards (dow) 19940801 - Foreword to amendment Al The text of document 12E(C0)164
23、, future amendment 1 to IEC 8351-2 : 1992, prepared by SC 12E, Radierelay and satellite communications systems, of IEC TC 12, Radiocommunications, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as amendment Al to EN 608351-2 : 1993 on 19954306. The following dates were fu
24、red - latest date by which the amendment has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1996-03-01 latest date by which the national standards confiicting with the amendment have to be withdrawn (dow) 19960301 - iib O BSI 1997 STD*BSI
25、 BS EN b0835-1-2-ENGL 1995 1b24bb9 Ob39527 9b5 W 835-1-2 IEC INTRODUCTION Modern test sets often combine a number of different measurement functions under the control of a microprocessor. In this way generally more than one parameter is checked and analysed step-by-step in accordance with specific s
26、oftware programmes. The results of the measurements are printed or plotted automatically and the programme description and tolerance analysis form part of the presentation of results. An example of such specialized equipment is a network analyser which combines two and four-port measurement faciliti
27、es in one microprocessor-controlled unit. iii STD-BSI BS EN bO835-L-Z-ENGL 1775 m Lb2LibbS 0b37530 b87 m 835-1-2 IEC METHODS OF MEASUREMENT FOR EQUIPMENT USED IN DIGITAL MICROWAVE RADIO TRANSMISSION SYSTEMS Part 1 : Measurements common to terrestrial radio-relay systems and satellite earth stations
28、Section 2: Basic Characteristics 1 Scope This section of IEC 835-1 deals with the measurement of basic characteristics common to terrestrial radio-relay systems and satellite earth stations. These basic characteristics apply to all of the frequency ranges employed in the radio systems, .e: - radio f
29、requency; - intermediate frequency; - baseband (e.g. clock frequency of the digital baseband signal). The method of measurement for each parameter (e.g. return loss) is presented, wherever possible, as a single clause which is applicable to any of the above frequency ranges. Where exceptions occur,
30、they will be given in the relevant clauses. 2 Carrier frequency 2.1 Definition and general consideration The carrier frequency is that frequency in the r.f. signal spectrum which is modulated by the information, or baseband, signal. The carrier frequency is normally measured without modulation. If e
31、nergy dispersal is employed, it should be rendered inoperative, if possible, before making measurements. 2.2 Methods of measurement The arrangement for measuring frequency using a counter or digital frequency-meter is shown in figure 1. The band-pass filter is required only if spurious signals are p
32、resent. The amplifier and/or attenuator are required only if the input range of the frequency-meter does not cover the range of levels concerned. Both the equipment under test and the test equipment itself should be allowed to attain thermal stability before making any measurements. The digital freq
33、uency-meter indications are then read during an interval of, for example, one second, depending upon the integrating time of the instrument used. Alternatively, a recorder may be used to record the indications of the digital frequency- meter for a number of counts. The number of counts will depend u
34、pon whether noise is present or not, and whether this modulates the signal or is superimposed upon it. 1 STD-BSI BS EN b835-1-2-ENGL 1775 H 1bZLibbS Ob39531 513 m 835-1-2 IEC Generally, the analysis of a statistical series averaged over several measuring intervals will provide evidence of the repeat
35、ability of the results. NOTE - The above method may also be used when the r.f. carrier is modulated by a zero mean baseband signai, provided that the digital frequency-meter does not introduce errors which depend upon the modulating signal. The averaging interval of the digital frequency-meter shoul
36、d exceed 100 cycles of the modulating signal. Alternatively, e.9. when performing frequency measurements on baseband signals, where a long time is required (10 s or more), several counter readings with a short averaging time can be taken and the average of these readings calculated. There are also o
37、ther methods applicable for carrier frequency measurement with modulation. For example, the substitution or interference method using a spectrum analyser as an indicator in conjunction with a synthesizer as a reference frequency source. 2.3 Presentation of results The readings of the digital frequen
38、cy-meter should be recorded manually or automatically as a function of time. The integrating time and the accuracy of the digital frequency-meter should be stated. When several counter readings are taken they should be tabulated, together with the calculated average value. The measured accuracy can
39、be expressed as an absolute value, e.g. 50 kHz, or as a fractional value, e.g. one part in The nominal carrier frequency should also be stated. 2.4 Details to be specified The following items should be included, as required, in the detailed equipment specif ication: a) nominal value of frequency and
40、 required accuracy; b) the pari of the equipment to be measured and the pori at which the measurement is to be made; c) permitted frequency tolerance. 3 Spectrum It is necessary to evaluate the spectrum which is to be transmitted by the radio-relay or satellite earth station in terms of wanted or un
41、wanted signals. Wanted signals within the necessary bandwidth are treated under “signal spectrum“, and unwanted signals which appear outside the necessary bandwidth are treated under “spurious emissions“. 3.1 Signal spectrum 3.1 .l In accordance with reference 1 the spectrum of a modulated signal is
42、 defined by the following characteristics: Definitions and general considerations - necessary bandwidth: - occupied bandwidth; - out-of-band signal; - unwanted spectrum components. 2 STD-BSI BS EN b0835-1-2-ENGL 1775 m Lb24bb7 Ub37532 45T m 835-1-2 IEC The necessary bandwidth is a theoretical value
43、which ensures that the information will be transmitted with the required quality, whereas the occupied bandwidfh is a measurable value within which a specified percentage of the total power of a given signal should lie (e.g. 99 %). The out-of-band signal is that part of the signal which is outside t
44、he necessary bandwidth and results from the modulation process and/or caused by spectral restoration or spectral spreading. Unwanted spectrum components within the necessary bandwidth are also measured. NOTE - Unwanted components with an inadmissibly high level in the transmitted signal usually adve
45、rsely affect the error ratio. These components therefore have a different significance in digital systems than in analogue systems. 3.1.2 Methods of measurement A suitable measuring arrangement is shown in figure 2. To measure the spectrum of the modulated signal, a random bit sequence modulation ma
46、y be applied. This bit sequence is usually generated by a pseudo-random generator (e.9. a sequence of 223 - 1 bits for 140 Mbit/s systems). The resolution bandwidth of the analyser should be greater than the bit rate of the pseudo-random bit sf?uence by a factor of 50 to 100 (e.g. for a bit rate of
47、34 Mbit/s and a sequence of 2 - 1 bits, the resolution bandwidth is (50:lOO) x 34 . 106/(2” - l), approximately 50:lOO kHz). To measure the level of the unwanted components within the necessary bandwidth it is necessary to operate the equipment under test without modulation. 3.2 Spectrum of spurious
48、 components 3.2.1 Definition and general considerations According to the Radio Regulations, a spurious emission is an emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information
49、. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequency conversion products, but exclude out-of-band emissions. Unwanted signal components may be divided into two categories: i) Spurious components excluding intermodulation products but including: - harmonic signals; - parasitic signals; - frequency conversion products. i) Intermodulation products 3 Harmonics are components hating a frequency n times that of the wanted signal, where n is an integer greater than 1. Intermodulation products are ge
