BS EN 60244-14-1997 Methods of measurement for radio transmitters - External intermodulation products caused by two or more transmitters using the same or adjacent antennas《无线电发射机测.pdf

1、BRITISH STANDARD BS EN 60244-14:1997 IEC60244-14: 1997 Methods of measurement for radio transmitters Part 14: External intermodulation products caused by two or more transmitters using the same or adjacent antennas The European Standard EN60244-14:1997 has the status of a British Standard ICS 33.060

2、.20BSEN60244-14:1997 This British Standard, having been prepared under the directionof the Electrotechnical Sector Board, was published underthe authority of theStandards Board andcomes intoeffect on 15October1997 BSI 09-1999 ISBN 0 580 28440 9 National foreword This British Standard is the English

3、language version of EN60244-14:1997. Itis identical with IEC60244-14:1997. The UK participation in its preparation was entrusted to Technical Committee EPL/103, Transmitting equipment for radiocommunication, which has the responsibility to: aid enquirers to understand the text; present to the respon

4、sible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UKinterests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on requ

5、est to its secretary. From1January1997, all IEC publications have the number60000added to the old number. For instance, IEC27-1 has been renumbered as IEC60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both system

6、s. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding or European publications. The BritishStandards which implement these international or European publicati

7、ons may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of Br

8、itish Standards are responsible 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, pagesi andii, theEN title page, pages2 to20 and a back cover. Th

9、is standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSEN60244-14:1997 BSI 09-1999 i Contents Page National foreword Inside front

10、cover Foreword 2 Text of EN 60244-14 3ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60244-14 July1997 ICS 33.060.20 Descriptors: Radiocommunications, radio equipment, transmitters, measurements, performance evaluation, quality, intermodulation, radio disturbances English version Metho

11、ds of measurement for radio transmitters Part 14: External intermodulation products caused by two or more transmitters using the same or adjacent antennas (IEC 60244-14:1997) Mthodes de mesure applicables aux metteurs radiolectriques Partie 14: Produits dintermodulation lextrieur du canal provoqus p

12、ar deux metteurs ou plus utilisant la mme antenne ou des antennes adjacentes (CEI 60244-14:1997) Meverfahren fr Funksender Teil 14: Externe Intermodulationsprodukte, verursacht durch zwei oder mehr Sender, welche gleiche oder benachbarte Antennen benutzen (IEC 60244-14:1997) This European Standard w

13、as approved by CENELEC on1997-07-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning suc

14、h 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, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own l

15、anguage and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden

16、, Switzerland and UnitedKingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1997 CENELEC All rights of exploitation in any fo

17、rm and by any means reserved worldwide for CENELEC members. Ref.No.EN60244-14:1997EEN60244-14:1997 BSI 09-1999 2 Foreword The text of document103/2/FDIS, future edition1 of IEC60244-14, prepared by SC12C (transformed into IECTC103, Transmitting equipment for radiocommunication), was submitted to the

18、 IEC-CENELEC parallel vote and was approved by CENELEC as EN60244-14 on1997-07-01. The following dates were fixed: Endorsement notice The text of the International Standard IEC60244-14:1997 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 Introduction

19、 3 1 Scope 3 2 Normative references 3 3 Definitions 3 4 General measuring procedure 4 4.1 Introduction 4 4.2 Measurements in transmitter feeders 4 4.3 Precautions to be observed when making measurements 4 4.4 Off-air measurements 4 4.5 Special precautions to be observed when making off-air measureme

20、nts 5 5 Methods of measurement for specific transmitter service or configuration 5 5.1 Measurements for VHF radio transmitters 5 5.2 Measurements for adjacent antennas 5 5.3 Measurements for a common antenna 5 6 Presentation of the results 6 Annex A (normative) Theoretical notes 13 Annex B (informat

21、ive) Calculation of radiated levels of intermodulation products (q=1) 15 Annex C (informative) Maximum permittedpowerlevel of spurious emissions 16 Figure 1 Measurements in transmitter feeders 7 Figure 2 Off-air measurements 8 Figure 3 General arrangement for transmittersfeeding separate antennas 9

22、Figure 4 General arrangement for transmittersfeeding a single antenna 10 Figure 5 Alternative arrangement for transmitters feeding a single antenna 11 Figure 6 Typical HF station configurations 12 latest date by which the ENhas to be implemented atnational level by publication of an identical nation

23、al standard or by endorsement (dop) 1998-04-01 latest date by which the national standards conflicting with the EN haveto be withdrawn (dow) 1998-04-01EN60244-14:1997 BSI 09-1999 3 Introduction Following the decision of the World Administrative Radio Conference held at Geneva in1979 to extend the VH

24、F/FM broadcast band to108MHz, the ITU-R 1)has recommended more stringent limits on spurious emissions in some circumstances than those called for by the ITU Radio Regulations, in order to avoid interference to the aeronautical services. Annex C, reproduced from CCIR Recommendation329-6, summarizes i

25、n the form of a graph the requirements given in Provision304 and Appendix8 of the Radio Regulations, Geneva1990 (seealso Provisions138,139,146 and163 of the Radio Regulations, RR1-18/19/20/23, Sec.VI andVII). 1 Scope This part of IEC60244 details a measurement method for external intermodulation pro

26、ducts (intermodulation components) caused by two or more transmitters using the same or adjacent antennas. It describes recommended methods of assessing the performance of radio broadcast transmitters. The purpose of the measurements described in clauses4 and5 of this part is to prove, as far as pos

27、sible, that the requirements of the Radio Regulations with respect to maximum permissible radiated levels of intermodulation products from LF, MF, HF, VHF, UHF and SHF transmitters will be fulfilled when two or more transmitters use the same or nearby antennas. The method of measurement given in thi

28、s part is not appropriate for type tests and IT SHOULD BE NOTED THAT THE MEASUREMENTS ARE TO BE CARRIED OUT ONLY WHEN MUTUALLY AGREED between the purchaser and supplier of the equipment. 2 Normative references The following normative documents contain provisions which, through reference in this text

29、, constitute provisions of this part of IEC60244. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC60244 are encouraged to investigate the possibility of applying the most recent edition

30、s of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ITU-R 1)Recommendation329-6:1994, Spurious emissions (Fasc.I). Radio Regulations and Appendices: Geneva1990 3 Definitions For the purpose of this part of IEC60244, the

31、following definitions apply. 3.1 external intermodulation products and spurious emission intermodulation products are classified by the Radio Regulations as spurious emissions, i.e.,emissions on frequencies outside the necessary bandwidth, the levels of which may be reduced without affecting the cor

32、responding transmission of information. In addition to intermodulation products, spurious emissions include harmonic emissions, parasitic emissions and frequency conversion products, but exclude out-of-band emissions external intermodulation products result from intermodulation between the various t

33、ransmissions when different transmitters make use of antennas located close together, or share the same antenna the external intermodulation products (components) may be caused by non-linearity in the output stage of a transmitter if the transmission from another transmitter is superimposed on its o

34、wn. Such intermodulation may result from coupling between open transmission lines, switching units, nearby antennas (seeFigure 6) or imperfect separation in the combining network between transmitters sharing the same antenna. External intermodulation products may also be produced if an interfering t

35、ransmission penetrates the driver stages of a transmitter 3.2 out-of-band emission emission on a frequency or frequencies immediately outside the necessary bandwidth which results from the modulation process, but excluding spurious emissions 3.3 harmful interference interference which endangers the

36、functioning of a radionavigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with the Radio Regulations 1) Formerly CCIR.EN60244-14:1997 4 BSI 09-1999 3.4 necessary bandwidth for a given class of

37、emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate given and with the quality required under specified conditions 3.5 type A-mode interference (applies to VHF/FM broadcast services only) type A-mode interference relates to interfe

38、rence radiated from VHF/FM broadcast transmitters at or near the frequency of aeronautical services in the adjacent band from108MHz to137MHz the ITU-R subdivides type A-mode interference into type A1-mode and type A2-mode Type A1-mode interference comprises radiated intermodulation products from bro

39、adcast transmitters generated in the aeronautical band from108MHz to137MHz. It is generally a low-level effect but may be of significance at100dB, or lower, relative to the transmitter carrier reference level. It is a form of spurious emission and can be regarded as harmful interference as defined i

40、n the Radio Regulations. Type A2-mode interference relates to out-of-band emissions from broadcast transmitters on frequencies just below108MHz to aeronautical services just above108MHz. 4 General measuring procedure 4.1 Introduction The following procedures assume the measurements are made manually

41、 using readily available test equipment and components. However, the precautions which need to be observed to avoid errors also apply to automatic measurements using specially designed equipment for the continuous monitoring of critical transmitter installations. The methods described are suitable f

42、or measurements of type A1-mode interference down to at least100dB relative to the reference carrier level. Theoretical considerations, including nomenclature used in all formulae in this standard, are detailed in Annex A. Procedures are given for on-site measurements of signals derived from directi

43、onal couplers in the feeders between the transmitters and the antennas and also for off-air measurements. 4.2 Measurements in transmitter feeders a) The test equipment is connected to the transmitter system which is to be measured as shown in Figure 1. b) With the stop filters (one for each transmis

44、sion) switched out of circuit, measure the levels of the unmodulated carrier frequencies to establish a reference level against which intermodulation products (hereinafter “IPs”) can be measured. If the transmitter powers are not equal, the lowest power transmission should be used as the reference.

45、c) Switch in all the stop filters and tune each to give maximum attenuation at the appropriate carrier frequency so that each of the carriers is attenuated by approximately55dB, for example. (The attenuation is to be determined by the dynamic range of the spectrum analyzer.) d) Calculate the frequen

46、cies at which IPs can be expected to occur using the formulae given in clauseA.2, and measure the level of each of these IPs relative to the reference carrier, using the spectrum analyzer. 4.3 Precautions to be observed when making measurements a) Ensure that levels into the spectrum analyzer are su

47、fficiently low to avoid IP generation within the analyzer itself. This may be checked simply by attenuating the input to the spectrum analyzer by3dB and noting that all IPs are also reduced by3dB. b) Verify that signals identified as IPs are generated in the transmitter system by switching off the t

48、ransmitters in turn. c) Correct the measured values of the IPs to allow for any differences in performance at the carrier frequencies and IP frequencies of the following: directional coupler; stop filter insertion loss (this is particularly important for any IP close to a carrier frequency); main tr

49、ansmitting feeder loss. NOTEThe measurement described in 4.2 does not represent the actual radiated level from the antenna. To obtain the radiated level, correct the results as described in 4.3 c), taking into account the frequency response and/or VSWR of the antenna. 4.4 Off-air measurements a) Connect the test equipment to a calibrated broad-band receiving antenna at the location where the measurements are to be made, as shown in Figure 2. b) Carry out the tests described in4.2 b),4.2 c), and4.2 d).EN60244-14:1997 BSI 09-