1、BRITISH STANDARD BS EN 60244-8:1995 IEC 244-8: 1993 Methods of measurement for radio transmitters Part 8: Performance characteristics of vestigial-sideband demodulators used for testing television transmitters and transposers The European Standard EN 60244-8:1994 has the status of a British Standard
2、BSEN60244-8:1995 This British Standard, having been prepared under the directionof the ElectrotechnicalSector Board,was published under theauthorityof the StandardsBoardand comesintoeffect on 15September1995 BSI 12-1999 The following BSI references relate to the work on this standard: Committee refe
3、rence EPL/12 Special announcement in BSINews March 1995 ISBN 0 580 24669 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EPL/12, Radiocommunication, upon which the following bodies were represented: British Broadcasting
4、 Corporation British Radio and Electronic Equipment Manufacturers Association British Telecommunications plc Institution of Electrical Engineers Radio, Electrical and Television Retailers Association Radiocommunications Agency Amendments issued since publication Amd. No. Date CommentsBSEN60244-8:199
5、5 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 60244-8 3 List of references Inside back coverBSEN60244-8:1995 ii BSI 12-1999 National foreword This British Standard has been prepared by Technical Committee EPL/12 and is the English
6、language version of EN60244-8:1994 Methods of measurement for radio transmitters Part 8: Performance characteristics of vestigial-sideband demodulators used for testing television transmitters and transposers, published by the European Committee for Electrotechnical Standardization (CENELEC). It is
7、identical with IEC244-8:1993, published by the International Electrotechnical Commission (IEC) and is part of a series describing recommended methods of measurement for assessing the performance of radio transmitters. This Part is intended to be used for type tests and acceptance or factory tests an
8、d can be used to check the performance characteristics of a VSB demodulator used for measuring television transmitters and transposers. The measuring arrangement and method of measurement is, in most cases, identical with that described in BSEN60244-5 Methods of measurements for radio transmitters P
9、art5:1995 Performance characteristics of television transmitters, provided that the television transmitter is replaced by a high-quality, double-sideband (DSB) modulator capable of delivering test signals suitable for measuring an instrument which is significantly better in performance than a televi
10、sion transmitter. Some other measurements, using RF generators to simulate vision and sound carriers and sideband signals, are fully described. This Part is intended to be used in conjunction with BSEN60244-5:1995. To facilitate reproduction, some of the figures retain the French text. Other Parts o
11、f BS EN 60244 published to date are: It is anticipated that other Parts of IEC Publication 244 will be published as identical British Standards, subject to their harmonization by CENELEC. Part 5:1995 Performance characteristics of television transmitters Part 10:1993 Methods of measurement for telev
12、ision transmitters and transposers employing insertion test signals Part 11:1993 Transposers for FM sound broadcasting Part 12: Guideline for drawing up descriptive leaflets for transmitters and transposers for sound and television broadcasting Section 12.1:1994 Characteristics to be specified Secti
13、on 12.2:1994 Specification sheets Part 13:1993 Performance characteristics for FM sound broadcasting Cross-references Publication referred to Corresponding British Standard BS EN 60244 Methods of measurement for radio transmitters EN 60244-5:1994 (IEC 244-5:1992) Part 5:1995 Performance characterist
14、ics of television transmitters EN 60244-10:1993 (IEC 244-10:1986) Part 10:1993 Methods of measurement for television transmitters and transposers employing insertion test signals Part 12 Guideline for drawing up descriptive leaflets for transmitters and transposers for sound and television broadcast
15、ing EN 60244-12-1:1993 (IEC 244-12-1:1989) Section 12.1:1994 Characteristics to be specified EN 60244-12-2:1993 (IEC 244-12-2:1989) Section 12.2:1994 Specification sheetsBSEN60244-8:1995 BSI 12-1999 iii A British Standard does not purport to include all the necessary provisions of a contract. Users
16、of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Publication referred to Corresponding British Standard EN 60244-13:1993 (IEC 244-13:1991) Part 13:1993 Performance characteristics for FM
17、sound broadcasting Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, theENtitle page, pages2to16, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in t
18、he amendment table on the inside front cover.iv blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60244-8 September 1994 ICS 33.060.20 Supersedes HD 236.8 S2:1987 Descriptors: Radio transmitters, measurement, television, vestigial-sideband demodulator, requirements, properties English versio
19、n Methods of measurement for radio transmitters Part8:Performance characteristics of vestigial-sideband demodulators used for testing television transmitters and transposers (IEC244-8:1993) Mthodes de mesure applicables aux metteursradiolectriques Partie8:Qualitdefonctionnement des dmodulateurs band
20、e latrale rsiduelle utiliss pour les essais des metteurs et rmetteurs de tlvision (CEI 244-8:1993) Meverfahren fr Funksender Teil8:bertragungs-eigenschaften von Restseitenband-Demodulatoren zur Prfung von Fernsehsendern und Umsetzern (IEC 244-8:1993) This European Standard was approved by CENELEC on
21、 1994-07-05. 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 such national standards may
22、 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 language and notified to
23、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, Switzerland and United
24、 Kingdom. 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 1994 Copyright reserved to CENELEC members Ref. No. EN 60244-8:1994 EEN6
25、0244-8:1994 BSI 12-1999 2 Foreword The CENELEC questionnaire procedure, performed for finding out whether or not the International Standard IEC244-8:1993 could be accepted without textual changes, has shown that no common modifications were necessary for acceptance as a European Standard. The refere
26、nce document was submitted to the CENELEC members for formal vote and was approved by CENELEC as EN60244-8 on5July1994. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. Annexes designated “informative” are given only for information. In this standa
27、rd, Annex A is informative andAnnex ZA is normative. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative references 3 3 General terms and definitions 3 4 General conditions of operation and measurement 4 5 Measuring arrangements and standard video test signals 4 6 Demodulator input and out
28、put characteristics 5 7 Linear distortion 6 8 Non-linear distortion 9 9 Wave-form distortion 9 10 Unwanted modulation 9 11 Special measurements for data signals in the vision signal 10 12 Measurements relative to the synchronous-detection mode 10 13 Performance of the sound section 11 Annex A (infor
29、mative) Input impedance 15 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications 16 Figure 1 Measuring arrangement 12 Figure 2a Example of Nyquist slope characteristic template, system B/G 13 Figure 2b Example of the a
30、mplitude/video-frequency characteristic template, system B/G, sound trap out of circuit 13 Figure 2c Example of the amplitude/video-frequency characteristic template, system B/G, sound trap in circuit 14 Figure 2d Example of the group delay receiver precorrection for system B/G curve with tolerances
31、 14 latest date of publication ofan identical national standard (dop) 1995-07-15 latest date of withdrawal ofconflicting national standards (dow) 1995-07-15EN60244-8:1994 BSI 12-1999 3 Introduction International Standard IEC244-8 is one of a series of parts of IEC244. A vestigial-sideband (VSB) demo
32、dulator is a measuring instrument for assessing the performance characteristics of television transmitters, for which the method of measurement is described in IEC244-5. The measuring arrangement and the method of measurement for the VSB demodulator is therefore in most cases identical with that in
33、IEC244-5, with the understanding that the television transmitter is replaced by a high-quality, double-sideband (DSB) modulator which is capable of delivering test signals suitable for measuring an instrument which is significantly better in performance than a television transmitter. Therefore, for
34、most measurements, reference is made toIEC 244-5. A number of measurements, using radio-frequency generators to simulate vision and sound carriers and sideband signals, are fully described in this standard. 1 Scope This part of IEC244 is intended to be used for type tests and acceptance or factory t
35、ests and may be used to check the characteristics of a demodulator used for measuring television transmitters and transposers. It is not mandatory to measure all the described characteristics. Additional measurements may be carried out by agreement between customer and manufacturer. Measuring perfor
36、mance characteristics in accordance with this standard, makes the comparison of the results of measurements, made by different observers, possible. Limit values for acceptable performance are not normally specified, but, in connection with the presentation of measured characteristics, some figures c
37、an be given for the sake of clarity. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC244. At the time of publication, the editions indicated were valid. All normative documents are subject to
38、revision, and parties to agreements based on this part of IEC244 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 244-1:1968, Method
39、s of measurement for radio transmitters Part 1: General conditions of measurement, frequency, output power and power consumption (revision under consideration). Amendment 2, 1989 IEC 244-5:1992, Methods of measurement for radio transmitters Part 5: Performance characteristics of television transmitt
40、ers. IEC 244-10:1986, Methods of measurement for radiotransmitters. Part 10: Methods of measurement for television transmitters and transposers employing insertion test signals. IEC 244-12-1:1989, Methods of measurement for radio transmitters Part 12: Guideline for drawing up descriptive leaflets fo
41、r transmitters and transposers for sound and television broadcasting Characteristics to be specified. IEC 244-12-2:1989, Methods of measurement for radio transmitters Part 12: Guideline for drawing up descriptive leaflets for transmitters and transposers for sound and television broadcasting Specifi
42、cation sheets. IEC 487-1:1984, Methods of measurement for equipment used in terrestrial radio-relay systems Part 1: Measurements common to sub-systems and simulated radio-relay systems. IEC 864-1:1986, Standardization of interconnections between broadcasting transmitters or transmitter systems and s
43、upervisory equipment Part 1: Interface standards for systems using dedicated interconnections. Amendment 1, 1987 CCIR Report 404-2:1974, Distortion of television signals due to the use of vestigial sideband emissions. 3 General terms and definitions 3.1 vestigial-sideband demodulator the term vestig
44、ial-sideband demodulator, sometimes referred to as a “Nyquist demodulator”, is used in this standard to refer to that equipment with one or more radio-frequency inputs and with one or more demodulated video and audio outputs the demodulator shall include: a “zero carrier” reference pulse; true synch
45、ronous and envelope detection, switchable; in the case of synchronous detection, a quadrature video output;EN60244-8:1994 4 BSI 12-1999 a switchable “sound trap” and associated group delay correction filter (with the sound trap switched out, the phase/frequency characteristic shall be linear); indep
46、endent (direct) sound demodulation, and intercarrier sound demodulation may be used; in the case of multiple sound channels, a suitable demodulator and decoder, and analogue or digital sound outputs depending on the system concerned. 3.2 description of the television systems and other relevant infor
47、mation see Annex A of IEC244-5 3.3 Definitions relating to the demodulator output and input signals 3.3.1 output voltage the peak-to-peak voltage of the video output signal 3.3.2 reference output level an output voltage of1V between sync pulse level and white level 3.3.3 input voltage the voltage of
48、 the vision signal at the input of a demodulator for negative (or positive) modulation of the vision carrier is the r.m.s. voltage, expressed in mV or dB(mV), of a sinusoidal signal with an amplitude corresponding to the synchronizing pulse level (or white reference level) of that signal 3.3.4 input
49、 voltage range the input voltage range of a demodulator is the range of input voltages within which the demodulator can deliver the reference output level within its performance specifications by adjusting the input attenuator of the demodulator 4 General conditions of operation and measurement The vestigial-sideband demodulator shall be tested under normal operating conditions. A sufficient warm-up time, in accordance with the demodulator specification, shall be allowed before commencing measurements. T
