1、BRITISH STANDARD BS EN 60835-3-6:1997 BS 7573-3.6: 1997 IEC 835-3-6: 1996 Methods of measurement for equipment used in digital microwave radio transmission systems Part 3: Measurements on satellite earth stations Section 3.6 High-power amplifiers The European Standard EN60835-3-6:1996 has the status
2、 of a British Standard ICS 33.060.30BSEN60835-3-6:1997 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 15January1997 BSI 11-1998 The following BSI references relate
3、 to the work on this standard: Committee reference EPL/12/5 Draft for comment 95/210490 DC ISBN 0 580 26393 2 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, Radio co
4、mmunication 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 Retailers A
5、ssociation Radiocommunications Agency Amendments issued since publication Amd. No. Date CommentsBSEN60835-3-6:1997 BSI 11-1998 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN60835-3-6 3 List of references Inside back coverBSEN60835-3-6:1997 ii BSI
6、 11-1998 National foreword This British Standard has been prepared by Subcommittee EPL/12/5 and is the English language version of EN60835-3-6:1996 Methods of measurement for equipment used in digital microwave radio transmission systems Part3:Measurements on satellite earth stations Section6 High-p
7、ower amplifiers, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC835-3-6:1996, published by the International Electrotechnical Commission (IEC). BS EN 60835 is published in three Parts. The other Parts are: Part 1: Measurements common to te
8、rrestrial radio-relay systems and satellite earth stations; Part 2: Measurements on terrestrial radio-relay systems. Some of the many Sections of the three Parts have appeared under the number BS7573, of the same generic title. This Section of BSEN60835 defines and describes measurements on high-pow
9、er amplifiers used in satellite earth station transmitters. 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-relay syste
10、ms 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) A British Standard does not purport to include all the necessary provisions of a contract. Users of
11、 British 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, pages i and ii, theENtitle page, pages 2 to 8, an inside back
12、 cover 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 cover. 1) In preparationEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60835-3-6 July 1996 ICS 33.060.30 Descr
13、iptors: Telecommunications, radiocommunications, communication equipment, power amplifiers, earth station, microwave frequencies, digital technics, measurements, characteristics English version Methods of measurement for equipment used in digital microwave radio transmission systems Part3:Measuremen
14、ts on satellite earth stations Section6:High power amplifiers (IEC 835-3-6:1996) Mthodes de mesure applicables au matriel utilis pour les systmes de transmission numrique en hyperfrquence Partie3:Mesures applicables aux stations terriennes de tlcommunications par satellite Section6: Amplificateurs d
15、e puissance (CEI835-3-6:1996) Meverfahren fr Gerte in digitalen Mikrowellen-Funkbertragungssystemen Teil3: Messungen an Satelliten-Erdfunkstellen Hauptabschnitt6: Hochleistungsverstrker (IEC835-3-6:1996) This European Standard was approved by CENELEC on 1996-07-02. CENELEC members are bound to compl
16、y 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 such national standards may be obtained on application to the Central Secr
17、etariat 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 language and notified to the Central Secretariat has the same status as
18、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, Switzerland and United Kingdom. CENELEC European Committee for Electr
19、otechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1996 Copyright reserved to CENELEC members Ref. No. EN 60835-3-6:1996 EEN60835-3-6:1996 2 BSI 11-1998 Foreword The text
20、 of document 12E/258/FDIS, future edition1 of IEC835-3-6, prepared by SC12E, Radio-relay and fixed satellite communication systems, of IECTC12, Radiocommunications, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN60835-3-6 on1996-07-02. The following dates were fixed:
21、 Annexes designated “normative” are part of the body of the standard. In this standard, annexZA is normative. AnnexZA has been added by CENELEC. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative references 3 3 Power gain and efficiency 3 4 Return loss 4 5 Spurious signals 4 6 Amplitude/f
22、requency characteristics 4 7 Group-delay/frequency characteristic 4 8 Amplitude modulation/phase modulation converstion factor 4 9 Intermodulation products 5 10 Unwanted radiation (leakage) 5 Annex ZA (normative) Normative references to international publications with their corresponding European pu
23、blications 8 Figure 1 Arrangement for gain stability measurement 6 Figure 2 Arrangement for intermodulation products measurement 6 Figure 3 Illustration of intercept point 7 Figure 4 Arrangement for unwanted r.f. radiation measurements 7 latest date by which the EN has to be implemented at national
24、level 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) 1997-04-01EN60835-3-6:1996 BSI 11-1998 3 Introduction Power amplifiers need to deliver a microwave signal of suffic
25、ient output power. This signal should be produced with maximum efficiency and reliability and with minimum distortion. Generally, there are two categories of amplifiers, tubes and semiconductor devices. Among the tubes, klystrons and travelling-wave tubes (TWT) are the most frequently employed; semi
26、conductor amplifiers normally include field-effect transistors (FET). Travelling-wave tubes (TWT) and GaAs-field-effect transistors (FET) are most frequently used in satellite earth stations. Power amplifiers should have a flat gain over the specified bandwidth to avoid altering the overall transfer
27、 characteristics of a system. They should also be as linear as possible to avoid generation of sidelobes in the power spectrum and to limit adjacent channel interference. Finally, low AM to PM conversion and low intermodulation products are necessary to limit the degradation caused by non-linearitie
28、s. 1 Scope This section of IEC835-3 defines and describes the measurements normally carried out on high-power amplifiers used in satellite earth station transmitters. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisi
29、ons of this section of IEC835-3. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this section of IEC835-3 are encouraged to investigate the possibility of applying the most recent editions of the norma
30、tive 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 used in digital microwave radio transmission systems Part1: Measurements common to terrestrial radio-relay systems and satellit
31、e earth stations Section 2: Basic characteristics. IEC 835-1-3:1992, Methods of measurement for equipment used in digital microwave radio transmission systems Part1: Measurements common to terrestrial radio-relay systems and satellite earth stations Section3: Transmission characteristics. 3 Power ga
32、in and efficiency 3.1 Input and output power See IEC 835-1-2. Special care shall be taken to exclude from the measurement non-useful signals such as harmonics of the desired frequency. A low-pass filter of known insertion loss at the measurement frequency shall be connected between the power meter a
33、nd the measurement point if not already included in the amplifier under test. NOTESome amplifiers are subject to damage if driven to excessive output power, therefore it may be necessary to limit the drive level during this measurement. 3.2 Power gain See IEC 835-1-2. High-power amplifiers are usual
34、ly operated in a non-linear power transfer characteristic region. For this reason, power gain values are given under at least two conditions: small-signal output power; rated output power, or saturated output power, where rated output power is not specified. In the case of TWT amplifiers, saturated
35、output power is often defined as that level for which a 1dB increase in input power results in a 0,1dB increase in output power. For solid-state amplifiers, frequently the 1dB compression point is used. The small-signal gain is the gain which is obtained when the amplifier operates in the linear por
36、tion of the input power/output power characteristic. The transfer characteristic is considered to be linear when the input power is sufficiently lower than that required to saturate the amplifier. If the high-power amplifier under test has gain control or level control the power gain shall be measur
37、ed at specified control settings 3.3 Efficiency The efficiency of an amplifier is given by the rated output power divided by the total primary power, including the power for heat exchangers or air-cooling equipment, if required, and is expressed as a percentage. 3.4 Gain stability 3.4.1 Definition T
38、he power gain stability of an amplifier is the variation in gain at a specified output power level and frequency over a specified period of time. It is convenient to distinguish between short-term stability (hours) and long-term stability (months). Gain stability is expressed in decibels.EN60835-3-6
39、:1996 4 BSI 11-1998 3.4.2 Method of measurement A suitable measuring arrangement is shown in Figure 1. After the amplifier under test has attained thermal stability, a signal of specified level and frequency is applied to the input port and the output power is adjusted to the specified level. The pa
40、rameters to be measured are recorded on a multi-track recorder for a specified period of time. This helps to reveal possible correlations between gain changes and parameter changes. These parameters are: RF output power level; RF input power level; primary power supply voltage(s); ambient temperatur
41、e or amplifier coolant temperature (whichever is applicable). 3.4.3 Presentation of results The parameters given in the preceding subclause shall be continuously recorded during the specified time interval(s) and the results presented as multi-track XY recordings. 3.4.4 Details to be specified The f
42、ollowing items should be included, as required, in the detailed equipment specification: a) input test-signal frequency; b) input test-signal level; c) output power; d) environmental conditions; e) period of time during which measurements are to be made; f) highest permitted gain fluctuations in the
43、 above time period. 4 Return loss See IEC 835-1-2. This measurement is usually made under “cold” conditions. This means that no electrode voltages are applied. 5 Spurious signals See IEC 835-1-2. 6 Amplitude/frequency characteristics See IEC 835-1-3. In some cases, a sweep-frequency method is recomm
44、ended but care should be taken to ensure that when sweeping the frequency across the band of interest with constant input power, the output power does not exceed the values recommended for safe operation of the amplifier under test. Since high-power amplifiers are non-linear, the output power shall
45、be specified. 7 Group-delay/frequency characteristic See IEC 835-1-3. When the f.m. method is used, the measurement equipment typically operates at an intermediate frequency which has to be up-converted to the frequency of the high-power amplifier and the signal from its output converted back to the
46、 intermediate frequency. With some types of amplifiers, the measurement equipment is liable to introduce a group delay of the same order as that to be measured. It is essential, therefore, to make the measurement with and without the high-power amplifier in circuit in the test arrangement, and to ca
47、lculate the difference between the two measurements. The phase shift through high-power amplifiers is dependent upon the r.f. drive level and it is important, therefore, that the drive level be kept constant over the sweep-frequency range. 8 Amplitude modulation/phase modulation conversion factor Se
48、e IEC 835-1-3. This parameter is important for modulation involving carrier amplitude changes (e.g. QAM).EN60835-3-6:1996 BSI 11-1998 5 9 Intermodulation products See IEC 835-1-2. The intermodulation products due to multicarrier amplification may vary across the operating frequency range of the ampl
49、ifier under test, so the test should therefore be repeated for several pairs of frequencies. The third order intermodulation product level varies by 3dB for a 1dB change in drive power when the amplifier is operated well below saturation. Figure 2 shows the measurement arrangement. In many cases it is convenient to specify the non-linear characteristics of the amplifier with one single number, the third order intercept point (IC P3 ). This is a fictitious power level, expressed in dBm, and denotes the intercept point
