1、BRITISH STANDARD BS EN 61580-2:1997 IEC1580-2: 1996 Methods of measurement for waveguides Part2: Level of intermodulation products The European Standard EN61580-2:1996 has the status of a British Standard ICS33.120.10BSEN61580-2:1997 This British Standard, having been prepared under the directionof
2、the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 February1997 BSI12-1998 The following BSI references relate to the work on this standard: Committee reference EPL/46/2 Draft announced in BSI Update October1996 ISBN0580269388 Comm
3、ittees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EPL/46, Cables, wires and waveguides, RF connectors and accessories for communication and signalling, to Subcommittee EPL/46/2, RFconnectors and waveguides, upon which the follo
4、wing bodies were represented: AEA Technology BEAMA Electrical Cable and Conductor Accessory Manufacturers British Non-Ferrous Metals Federation British Telecommunications plc Federation of the Electronics Industry Ministry of Defence National Supervisory Inspectorate Society of Cable Television Engi
5、neers Amendments issued since publication Amd. No. Date CommentsBSEN61580-2:1997 BSI 12-1998 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 61580-2 3BSEN61580-2:1997 ii BSI 12-1998 National foreword This British Standard has been prepared by Subc
6、ommittee EPL/46/2 and is the English language version of EN61580-2:1996 Methods of measurement for waveguides Part2: Level of intermodulation products, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC1580-2:1996 published by the Internation
7、al Electrotechnical Commission (IEC). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Sum
8、mary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2 to6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front co
9、ver.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN61580-2 August1996 ICS33.120.10 Descriptors: Waveguides, level of intermodulation products English version Methods of measurement for waveguides Part2:Levelofintermodulation products (IEC1580-2:1996) Mthodes de mesure appliques aux guides donde
10、s Partie2: Niveau des produits dintermodulation (CEI1580-2:1996) Meverfahren fr Hohlleiter Teil2:Intermodulationspegel (IEC1580-2:1996) This European Standard was approved by CENELEC on1996-07-02. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the condi
11、tions 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 exists in th
12、ree 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 electrotechni
13、cal 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 Electrotech
14、nique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart35, B-1050 Brussels 1996 Copyright reserved to CENELEC members Ref. No. EN61580-2:1996 EEN61580-2:1996 BSI 12-1998 2 Foreword The text of document46B/207/FDIS, future edition1 of IEC1580-2, prepared by SC46B,
15、Waveguides and their accessories, of IEC TC46, Cables, wires, waveguides, R.F. connectors, and accessories for communication and signalling, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN61580-2 on1996-07-02. The following dates were fixed: Contents Page Foreword 2
16、1 Scope 3 2 Principle 3 3 Set-up 3 3.1 Set-up 1 3 3.2 Test equipment 4 3.3 Set-up 2 4 3.4 Test equipment 4 4 Preparation of test specimen 4 5 Procedure 4 6 Expression of results 5 7 Requirements 5 Figure 1 Set-up 1 5 Figure 2 Set-up 2 6 latest date by which the EN has to be implemented at national l
17、evel by publication of an identical national standard or by endorsement (dop)1997-04-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow)1997-04-01EN61580-2:1996 BSI 12-1998 3 1 Scope This part of IEC1580 is applicable to intermodulation products in waveg
18、uides. The objective of the test procedure given below is to characterise the level of unwanted signals caused by the presence of two or more transmitting signals in waveguides or waveguide assemblies. The basic theory of the generation of intermodulation products in RF circuits is well described in
19、 the literature. In the case of passive waveguide components, intermodulation distortion is caused by sources of non-linearity of mostly unknown nature, location and behaviour. A few examples are: intermetallic contacts, corrosion products, dirt, etc. Most of these non-linearities generate measurabl
20、e intermodulation products only when exposed to relatively high RF-power levels (1 W). Threshold and cut-off effects are found frequently. In addition, most of these effects are subject to changes over time due to mechanical stress, temperature changes, variations in material characteristics (cold f
21、low, etc.), climatic changes and so on. NOTEThe generation of intermodulation products does not necessarily follow the law of the usual non-linear equation of quadratic form. Therefore, interpolation to higher or lower power levels causing the intermodulation is not allowed. On the other hand, sourc
22、es of intermodulation tend to be not frequency selective. This allows for testing waveguides at one particular frequency within the band of operation. 2 Principle For the test, signals of frequencies F p , F q , F r . F nwith equal power level are combined and fed to the waveguide under test. The te
23、st signal(s) should contain at least10dB less harmonic of self-intermodulation signal level than the expected level generated in the WUT. Using two generators with different frequencies F pand F qthe intermodulation products of the third order are measured with a calibrated receiver. The unwanted si
24、gnals in the waveguide frequency band are: In the case of three transmitting signals, the intermodulation products of third order are: Theoretically, the level of these intermodulation products are6dB higher than products measured with the two-signal method. To optimise the test set-up, normally the
25、 two-transmitter method will be used. NOTEExperience shows that the generation of intermodulation products originates from point-sources of radiation inside a WUT therefore; either the reflected or the transmitted intermodulation signal can be measured. In most cases, the third order intermodulation
26、 signals represent the worst-case condition of unwanted signals generated; therefore, the measurement of these signals characterise the WUT in a sufficient way. However, the test set-ups given in this procedure are also suitable for measuring intermodulation products of higher order. 3 Set-up Two di
27、fferent test set-ups are described. Both of them allow the measurement of intermodulation signals of more than100dB below carrier level. The set-up onFigure1 may be assembled from standard microwave radio link hardware selected for this particular application. There are two critical components in th
28、is configuration which must be carefully checked for lowest self-intermodulation generation: the summing device and the circulator used for the decoupling of the intermodulation signals. The set-up on Figure1 allows the combination of current laboratory signal generating devices with one power ampli
29、fier only. The self-intermodulation free measurement dynamic range depends only on the quality of the filter diplexer used for the decoupling of the intermodulation signals. NOTEThe results of measured intermodulation levels of WUT, with more than one flange generating intermodulation products, can
30、be falsified by super-position. To verify a reproducible measurement set-up, knocking the flanges with a screwdriver could be helpful. Experience shows that devices containing magnetic materials (circulators, isolators, etc.) can be prominent sources for intermodulation signal generation. 3.1 Set-up
31、1 Two or more high power signal sources or signal generators with power amplifiers are required to reach the specified sum power. The summing device may be a circulator, hybrid junction, coupler or filter network provided that the self-intermodulation generated is at least 10dB below the level to be
32、 measured on the WUT. The WUT shall be terminated by a load for the specified power if necessary. F k3=2F p F q F k3=2F q F p F K3=2F p+ F q F r F K3 , =2F q+ F r F p F K3 ,=2F r+ F q F pEN61580-2:1996 4 BSI 12-1998 The receiving band-pass filter, tuned for the desired intermodulation signal is foll
33、owed by a low-noise amplifier (if required) and a receiver. 3.2 Test equipment In order to reach level differences of100.150dB between the carrier level(s) and the intermodulation signals, high-performance test equipment is required. All components must be carefully chosen for lowest levels of self-
34、intermodulation generation (seenote4in3.3). The set-up illustrated inFigure1 consists of: signal generators, power output to produce the specified sum power; frequency stability to match the requirements of the measuring receiver; low-pass filters; isolators; power combiner (see note1 in3.3); circul
35、ator (see note2 in3.3); load; band-pass filter; low-noise amplifier; measuring receiver (see note3 in3.3); signal generator for level calibration. 3.3 Set-up2 The set-up inFigure2 consists of two or more frequency stabilised signal generators combined with a power-combiner or hybrid. NOTE1Alternativ
36、ely, circulator(s), directional coupler(s), hybrid junctions or filter networks may be used. NOTE2The circulator may be replaced by a filter diplexer. NOTE3The measuring receiver may be replaced by a spectrum analyser. NOTE4The interface flanges to the WUT are best constructed as A-type (choke) flan
37、ges for minimum intermodulation. For the combined signal, only one power amplifier allowing for the sum power specified for the intermodulation test is necessary. The high-pass filter at the amplifier output suppresses all intermodulation signals (2F p F q ,etc.) below F pand also the broadband nois
38、e, generated by the power amplifier. Furthermore, it acts as a diplexer system together with the receiving band filter. For this set-up, the low-pass/band-pass combination must be designed and selected for a self-intermodulation level of at least10dB below the level to be measured on the WUT. The re
39、ceiving band-pass filter, tuned for the lowest intermodulation signal as described, is followed by a low-noise amplifier (if required) and a receiver. As an alternative, high power generators or generators with individual power amplifiers can be combined to provide the necessary power level. Care mu
40、st be taken that the high power levels do not produce excessive intermodulation products in the summing devices. 3.4 Test equipment In order to reach level differences of100.150dB between the carrier level(s) and the intermodulation signals, high-performance test equipment is required. All component
41、s must be carefully chosen for lowest levels of self-intermodulation (see note4). The set-up illustrated inFigure2 consists of: signal generators; frequency stability to match the requirements of the measuring receiver; signal combiner (see note1); power amplifier for the specified sum power; filter
42、 diplexer formed by a waveguide below cut-off and a band-pass filter (seenote2); load; low-noise amplifier; measuring receiver (see note3); signal generator for level calibration. NOTE1Alternatively, circulator(s), directional coupler(s), hybrid junctions or filter networks may be used. NOTE2A waveg
43、uide below cut-off filter is preferred because of the very high suppression of the unwanted intermodulation product(s) possible. For proper diplexing function, the distance between the two filters shall be chosen carefully. NOTE3The measuring receiver may be replaced by a spectrum analyser. NOTE4The
44、 interface flanges to the WUT are best constructed as A-type (choke) flanges for minimum intermodulation. 4 Preparation of test specimen The WUT shall be carefully checked for proper power handling range, cleanliness and correct flange interconnection dimensions. 5 Procedure The set-up used shall fi
45、rst be calibrated for correct signal levels transmitted to the WUT. Then, the receiver shall be calibrated for correct level indication using a calibrated signal source. A load with the necessary power rating is then connected to the test port and the level of self-intermodulation generated by the d
46、ifferent components in the set-up is recorded. The level of self-intermodulation should be at least10dB below the specified value for WUT.EN61580-2:1996 BSI 12-1998 5 Then, the WUT is inserted and terminated with the same load as used for the calibration procedure. The level of intermodulation from
47、the WUT is read on the receiver. 6 Expression of results The results are expressed as intermodulation free range, for a given power level for the transmitted signal in the WUT. 7 Requirements Compliance with specifications. Figure1 Montage1 Set-up1EN61580-2:1996 6 BSI 12-1998 Figure2 Montage2 Set-up
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