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1、BRITISH STANDARD BS EN 50083-3:2002 Cable networks for television signals, sound signals and interactive services Part 3: Active wideband equipment for coaxial cable networks The European Standard EN 50083-3:2002 has the status of a British Standard ICS 33.060.40 NO COPYING WITHOUT BSI PERMISSION EX
2、CEPT AS PERMITTED BY COPYRIGHT LAW BS EN 50083-3:2002 This British Standard, having been prepared under the direction of the Electrotechnical Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 3 July 2002 BSI 3 July 2002 ISBN 0 5
3、80 40014 X National foreword This British Standard is the official English language version of EN 50083-3:2002. It supersedes BS EN 50083-3:1999 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee EPL/100, Audio, video and multimedia systems and equipment
4、, to Subcommittee EPL/100/4, Cable distribution systems, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in
5、 this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a
6、 contract. Users are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or prop
7、osals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 53 and a back cover. The BSI copyright date displa
8、yed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments EUROPEAN STANDARDEN 50083-3 NORME EUROPENNE EUROPISCHE NORMApril 2002 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotech
9、nique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2002 CENELEC -All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 50083-3:2002 E ICS 33.060.40Supersedes EN 50083-3:1998 English v
10、ersion Cable networks for television signals, sound signals and interactive services Part 3: Active wideband equipment for coaxial cable networks Rseaux de distribution par cbles pour signaux de tlvision, signaux de radiodiffusion sonore et services interactifs Partie 3: Matriels actifs large bande
11、utiliss dans les rseaux de distribution coaxiale Kabelnetze fr Fernsehsignale, Tonsignale und interaktive Dienste Teil 3: Aktive Breitbandgerte fr koaxiale Kabelnetze This European Standard was approved by CENELEC on 2001-10-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regul
12、ations 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. Thi
13、s 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 member
14、s are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EN 50083-3: 2002- 2 - Foreword This European Standa
15、rd was prepared by CENELEC Technical Committee TC 209, “Cable networks for television signals, sound signals and interactive services“ on the basis of EN 50083-3:1998 and the first amendment to EN 50083-3. The text of this first amendment was submitted to the Unique Acceptance Procedure and was appr
16、oved by CENELEC on 2001-10-01 to be published as part of a second edition of EN 50083-3. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement(dop)2002-10-01 latest date by which the nati
17、onal standards conflicting with the EN have to be withdrawn(dow)2004-10-01 Annexes designated “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard, Annexes A, B, C and D are normative and Annexes E and F are informative.
18、_ - 3 -EN 50083-3: 2002 Content 1Scope 5 1.1General 5 1.2Specific scope of this part 3 5 2Normative references.6 3Terms, definitions, symbols and abbreviations.7 3.1Terms and definitions . 7 3.2Symbols11 3.3Abbreviations.12 4Methods of measurement 13 4.1Linear distortion.13 4.2Non-linear distortion.
19、14 4.3Automatic gain and slope control step response.24 4.4Noise figure.25 4.5Cross talk attenuation26 4.6Signal level for digitally modulated signals .27 4.7Method of measurement for non-linearity of return path equipment carrying only digital modulated signals Measurement of composite intermodulat
20、ion noise ratio (CINR) .27 5Equipment requirements29 5.1General requirements29 5.2Safety29 5.3Electromagnetic compatibility (EMC)29 5.4Frequency range .29 5.5Impedance and return loss.29 5.6Gain29 5.7Flatness.30 5.8Test points.30 5.9Group delay.30 5.10Noise figure.30 5.11Non-linear distortion.30 5.1
21、2Automatic gain and slope control .31 5.13Hum modulation 31 5.14Power supply.32 5.15Environmental .32 5.16Marking.32 5.17Mean operating time between failure (MTBF).33 5.18Requirements for multiswitches .33 Annexes Annex A (normative) Test carriers, levels and intermodulation products 42 Annex B (nor
22、mative) Checks on test equipment.44 Annex C (normative) Table C.1 - Frequency allocation plan .45 Annex D (normative) Special national conditions46 Annex E (informative) Measurement errors which occur due to mismatched equipment .47 Annex F (informative) Examples of signals, methods of measurement a
23、nd network design for return paths 48 Tables Table 1 - Return loss requirements for all equipment.34 Table 2 - Correction factors where the modulation used is other than 100% 34 Table 3 - Notch filter frequencies.35 Table C.1 - Frequency allocation plan.45 Table F.1 - Application of methods of measu
24、rement in EN 50083-3 for return path equipment.48 Table F.2 - Application of methods of measurement in EN 50083-6 for return path equipment.49 EN 50083-3: 2002- 4 - Figures Figure 1 - Measurement of return loss.35 Figure 2 - Maximum error a for measurement of return loss using V.S.W.R. bridge with d
25、irectivity D = 46 dB and 26 dB test port return loss .35 Figure 3 - Basic arrangement of test equipment for evaluation of the ratio of signal to intermodulation product.36 Figure 4 - Connection of test equipment for the measurement of non-linear distortion by composite beat 36 Figure 5 - Connection
26、of test equipment for the measurement of composite crossmodulation.37 Figure 6 - Carrier/hum ratio = ? 20 lgdB? A a 37 Figure 7 - Test set-up for local-powered objects38 Figure 8 - Test set-up for remote-powered objects.38 Figure 9 - Oscilloscope display38 Figure 10 - Measurement of AGC step respons
27、e.39 Figure 11 - Time constant Tc.39 Figure 12 - Measurement of noise figure.39 Figure 13 - Presentation of the result of CINR .40 Figure 14 - Characteristic of the noise filter .40 Figure 15 - Test setup for the non-linearity measurement41 Figure 16 - Measurement of cross talk attenuation for loop
28、trough ports of multiswitches.41 Figure A.1 - An example showing products formed when 2?A ?B 42 Figure A.2 - An example showing products formed when 2?A 1 is a non-linear distortion product, where ? i is an integral multiple of a single term in the input signal, e.g. 4?2, the product is regarded as
29、a harmonic distortion product. If it is formed from two or more terms, e.g. 2?1 - ?3, it is known as an intermodulation distortion product. Since the values of a1, a2, a3, etc., usually decrease relatively rapidly with increasing values of n, it is found that the predominant non-linear output signal
30、s 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?1-2?3 is a fifth order product arising from the term a Vin 5 5 . - 15 -EN 50083-3: 2002 The m input signals represented in the express
31、ion are not necessarily distinct signals. Any periodic signal may be represented by a series of sinusoidal terms as in the expression for Vin. For the predominant non-linear output signals it is found that: m p m ppp iVVVVV. 321 321 ? so that if the amplitudes of all the input signals are multiplied
32、 by a common factor K, the amplitude of the nth order distortion products will be multiplied by Kn (since p1+p2+p3+.pm = n). When the levels of all input 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
33、will decrease by (n-1) dB. This relationship will be referred to as the “standard level variation“ of a distortion 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 distortio
34、n products, then the measured level will not follow a standard level variation. In principle, an infinite 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 contribution o
35、f higher-order terms increases with the level of input signals. Conversely, if signal levels are low enough, only a few of the lowest order terms will produce significant contributions at the output. If all input signals are limited to a frequency band of less than one octave, the frequencies of all
36、 second-order terms will fall outside the band limits. Signal frequencies can also be allocated in two or more 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 r
37、epresented by ?1 ? ?2 ? ?3 cannot be kept out of the band that contains the input signals. The accumulation of third-order distortion products may therefore be a limiting factor in the performance of a wideband multi-channel distribution system. 4.2.1.2 Measurement Measurements related to the follow
38、ing phenomena are described: ? intermodulation between two or three single frequency signals; ? composite beats produced 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 deta
39、ils: a)the particular effect that is measured; b)the required signal to distortion ratio. The result of the measurement 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 freq
40、uency, this shall be defined. The effect shall be defined as being of a particular order (e.g. “third-order intermodulation“). 4.2.2 Intermodulation 4.2.2.1 Introduction The two equal carrier and the three equal carrier methods described are applicable to the measurement of the ratio of the carrier
41、to a single intermodulation product at a specified point within the cable network. The methods can also be used to determine the intermodulation performance of individual items of equipment. NOTE 1 It should be especially noted that the simultaneous use of many channels spaced by the same frequency
42、interval results in a large number of intermodulation products (particularly those of the third-order) falling near the vision carrier of a wanted television channel. EN 50083-3: 2002- 16 - In these cases, the resultant interference is of an extremely complex nature and an alternative measurement pr
43、ocedure will be needed. This is covered in 4.2.3 and 4.2.4. Examples of second-order and third-order intermodulation products are 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 (se
44、e A.1). Third-order products are encountered in wideband and narrowband equipment and systems and shall be measured using three signals (see A.2). NOTE 2 If the unequal carrier method of measurement, as described in EN 50083-5, is used, the output level giving the appropriate signal to distortion ra
45、tio must be decreased by 6 dB to obtain the correct result for the equal carrier method described here. 4.2.2.2 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 appropriate number of signal gener
46、ators 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 4.2.2.2 a); d) A combiner will be required for tests on equipment and systems wi
47、th a single input (Figure 3); NOTE Additional 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). 4.2.2.3 Connection of equipment The equipment shall be connected as shown in Figure 3. 4.2.2.4 Meas
48、urement procedure The measurement procedure comprises the following steps: a)General Unless otherwise required, the reference output levels used in the measurements shall be the nominal output levels for the equipment. It shall be quoted whether the signal output levels are constant over the frequen
49、cy range or not. If the specified output levels are not constant over frequency range then the output levels off all the test signals shall be quoted in the results. Measurements of both second-order and third-order products shall be carried out with the test signals widely and closely spaced over each band of interest at frequencies capable of producing significant products within the overall frequency range. Where the equipment to be measured includes automatic gain control, tests shall be carried out at the nominal operati
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