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1、BRITISH STANDARD BS EN 50083-3:1995 Cabled distribution systems for television and sound signals Part 3: Active coaxial wideband distribution equipment The European Standard EN 50083-3:1994 has the status of a British Standard UDC 621.397.743 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07
2、:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 50083-3:1995 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board (L/1), was published under the authority of the Standards Board and comes into effect on 15 April 1995 BSI 03-1999 The following B
3、SI references relate to the work on this standard: Committee reference EEL/25 Draft for comment 91/32581 DC ISBN 0 580 23897 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EEL/25, Radio communication, upon which the fo
4、llowing bodies were represented: British Broadcasting Corporation British Radio and Electronic Equipment Manufacturers Association British Telecommunications plc Cable Television Association of Great Britain Confederation of Aerial Industries Electricity Association Institution of Electrical Enginee
5、rs Radio, Electrical and Television Retailers Association Radio communications Agency Society of Cable Television Engineers Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 50083-
6、3:1995 BSI 03-1999i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 50083-3 3 List of references Inside back cover Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 50083-3:1995 ii BSI 0
7、3-1999 National foreword This British Standard has been prepared by Technical Committee EEL/25 and is the English language version of EN 50083-3:1994 Cabled distribution systems for television and sound signals Part 3: Active coaxial wideband distribution equipment published by the European Committe
8、e for Electrotechnical Standardization (CENELEC). It forms Part 3 of a multi-Part standard on cabled distribution systems for television and sound signals. Other Parts to follow will cover terms and definitions, electromagnetic compatibility for components and systems, passive coaxial wideband distr
9、ibution equipment, headend equipment, optical equipment, system performance, digital cable television equipment for coaxial cabled distribution systems, and digital cable television equipment for optical cabled distribution systems. This Part specifies basic methods of measurement of the operational
10、 characteristics of one-way and two-way active equipment in order to assess its performance, identifies performance specifications to be published by manufacturers, and states the minimum performance requirements of certain parameters. It applies to all broadband amplifiers used in cabled distributi
11、on systems in the frequency range 5 MHz to 1 750 MHz. 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
12、obligations. Cross-references Publication referred toCorresponding British Standard EN 50083BS EN 50083 Cabled distribution systems for television and sound signals EN 50083-1:1993Part 1:1994 Safety requirements EN 50083-5:1994Part 5:1994 Headend equipment EN 60068BS EN 60068 Environmental testing H
13、D 323 seriesBS 2011 Environmental testing EN 60529:1991BS EN 60529:1992 Specifications for degrees of protection provided by enclosures (IP code) HD 571 S1BS 7477:1991 Guide for general principles for the creation of graphical symbols for use on equipment Summary of pages This document comprises a f
14、ront cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 28, 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 the amendment table on the inside front cover. Licensed
15、Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 50083-3 May 1994 UDC 621.397.743 Descriptors: Telecasting, cable television, sound broadcasting, community aerial systems, coaxial cables, components
16、, measuring techniques, specifications English version Cabled distribution systems for television and sound signals Part 3: Active coaxial wideband distribution equipment Systmes de distribution par cble destins aux signaux de radiodiffusion sonore et de tlvision Partie 3: Matriels actifs utiliss da
17、ns les systmes de distribution coaxiale large bande Kabelverteilsysteme fr Ton- und Fernsehrundfunk-Signale Teil 3: Aktive Breitbandgerte fur koaxiale Verteilnetze This European Standard was approved by CENELEC on 22 September 1993. CENELEC members are bound to comply with the CEN/CENELEC Internal R
18、egulations 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 Secretariat or to any CENELEC member.
19、 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 the official versions. CENELEC me
20、mbers 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 Electrotechnical Standardization Comit
21、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 50083-3:1994 E Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Un
22、controlled Copy, (c) BSI EN 50083-3:1994 BSI 03-1999 2 Foreword This European Standard was prepared by CENELEC Technical Committee TC 109, Cabled distribution systems for television and sound signals. The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50083-3 on
23、 1993-09-22. The following dates were fixed: For products which have complied with the relevant national standard before 1994-12-01, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 1999-12-01. Annexes designated “normative” a
24、re part of the body of the standard. In this standard, all annexes are normative. Contents Page Foreword2 1 Scope3 2 Terms and definitions3 3 Methods of measurement6 3.1 Linear distortion6 3.2 Non-linear distortion7 3.3 Automatic gain and slope control step response14 3.4 Noise figure15 4 Performanc
25、e requirements16 4.1 General requirements16 4.2 Safety16 4.3 Electromagnetic compatibility (EMC)16 4.4 Frequency range16 4.5 Impedance and return loss16 4.6 Gain16 4.7 Flatness17 4.8 Test points17 4.9 Group delay17 4.10 Noise figure17 4.11 Non-linear distortion17 4.12 Automatic gain and slope contro
26、l18 4.13 Hum modulation18 Page 4.14 Power supply18 4.15 Environmental18 4.16 Marking19 4.17 Mean operating time between failure (MTBF)19 Annex A (Normative) Test carriers, levels and intermodulation products24 Annex B (Normative) Checks on test equipment25 Annex C (Normative) Channel allocation for
27、CTB, CSO and cross modulation measurement27 Annex D (Normative) List of normative references28 Annex E (Normative) Special national conditions (SNC)28 Figure 1 Measurement of return loss20 Figure 2 Maximum error, a, for measurement of return loss using V.S.W.R. bridge with 46 dB directivity and 26 d
28、B test port return loss20 Figure 3 Basic arrangement of test equipment for evaluation of the ratio of signal to intermodulation product21 Figure 4 Connection of test equipment for the measurement of non-linear distortion by composite beat21 Figure 5 Connection of test equipment for the measurement o
29、f composite crossmodulation22 Figure 6 Measurement of a.g.c. step response22 Figure 7 Time constant Tc23 Figure 8 Measurement of noise figure23 Figure A.1 An example showing product formed when 2fa fb24 Figure A.2 An example showing products formed when 2fa 1 is a non-linear distortion product, wher
30、e to 6i is an integral multiple of a single term in the input signal, e.g. 4 62, the product is regarded as a harmonic distortion product. If it is formed from two or more terms, e.g. 2 61 63, it is known as an intermodulation distortion product. Since the values of a1, a2, a3, etc., usually decreas
31、e relatively rapidly with increasing values of n, it is found that the predominant non-linear output signals arise from the terms in the transfer function in such a way that the sum p1+ p2+ .pm= n, and n is defined as the order of the non-linear distortion product, e.g. 3 61 2 63 is a fifth order pr
32、oduct arising from the term a5Vin5. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 50083-3:1994 8 BSI 03-1999 The m input signals represented in the expression are not necessarily distinct signals. Any periodic signal may be represented
33、by a series of sinusoidal terms as in the expression for Vin. For the predominant non-linear output signals it is found that: so that if the amplitudes of all the input signals are multiplied by a common factor K, the amplitude of the nth order distortion products will be multiplied by Kn (since p1+
34、 p2+ p3+ .pn = n). When the levels of all inputs signals are raised by 1 dB, the level of any signal nth order distortion product will increase by n dB, and the resultant signal/distortion ratio will decrease by (n-1) dB. This relationship will be referred to as the “standard level variation” of a d
35、istortion product. If a distortion product is due to components of different order, and/or different order products occur within the bandwidth of the device used to measure the level of distortion products, then the measured level will not follow a standard level variation. In principle, an infinite
36、 number of terms is necessary for a complete description of a non-linear characteristic. However, considering the standard level variation of terms of different order, the relative conribution of higher-order terms increases with the level of input signals. Conversely, if signal levels are low enoug
37、h, only a few of the lowest order terms will produce significant conributions at the output. If all input signals are limited to a frequency band of less than one octave, the frequencies of all second-order terms will fall outside the band limits. Signal frequencies can also be allocated in two or m
38、ore non-contiguous bands in a manner that will place all second-order products outside the bands. Third-order distortion products, in particular some of the products that occur at frequencies represented by 61 62 63 cannot be kept out of the band that contains the input signals. The accumulation of
39、third-order distortion products may therefore be a limiting factor in the performance of a wideband multi-channel distribution system. 3.2.1.2 Measurement Measurements related to the following phenomena are described: intermodulation between two or three single frequency signals; composite beats pro
40、duced by a number of single frequency signals; composite crossmodulation between a number of single frequency signals. A proper specification shall include at least the following details: a) the particular effect that is measured; b) the required signal to distortion ratio. The result of the measure
41、ment shall be given as the worst case maximum signal level at the equipment output that allows the required signal to distortion ratio to be met. If the output level is sloped with frequency, this shall be defined. The effect shall be defined as being of a particular order (e.g. “third-order intermo
42、dulation”). 3.2.2 Intermodulation 3.2.2.1 Introduction The two equal carrier and the three equal carrier methods described are applicable to the measurement of the ratio of the carrier to a single intermodulation product at a specified point within the cabled distribution system. The methods can als
43、o be used to determine the intermodulation performance of individual items of equipment. NOTEIt should be especially noted that the simultaneous use of many channels spaced by the same frequency interval results in a large number of intermodulation products (particularly those of the third-order) fa
44、lling near the vision carrier of a wanted television channel. In these cases, the resultant interference is of an extremely complex nature and an alternative measurement procedure will be needed. This is covered in 3.2.3 and 3.2.4. Examples of second-order and third-order intermodulation products ar
45、e given in Annex A. Second-order products are encountered only in wideband equipment and systems, covering more than one octave, and shall be measured using two signals (see A.1). Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 06 07:55:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 50083-3:19
46、94 BSI 03-19999 Third-order products are encountered in wideband and narrowband equipment and systems and shall be measured using three signals (see A.2). NOTEIf the unequal carrier method of measurement, as described in subclauses 3.2 and 6.2.1.3 of EN 50083-5, is used, the output level giving the
47、appropriate signal to distortion ratio must be decreased by 6 dB to obtain the correct result for the equal carrier method described here. 3.2.2.2 Equipment required a) A selective voltmeter covering the frequency range of the equipment or system to be tested. This may be a spectrum analyser. b) The
48、 appropriate number of signal generators covering the frequencies at which the tests are to be carried out. c) A variable attenuator with a range greater than the signal to intermodulation ratio expected, if not incorporated in the voltmeter described in 3.2.2.2 a). d) A combiner will be required fo
49、r tests on equipment and systems with a single input (Figure 3). NOTEAdditional items may be necessary, for example to ensure that the measurements are not affected by spurious signals generated in the test equipment itself. (Annex B). 3.2.2.3 Connection of equipment The equipment shall be connected as shown in Figure 3. 3.2.2.4 Measurement procedure The measurement procedure comprises the following steps: a) General Unless otherwise required, the reference levels used in the measurements shall be the nominal output levels spe