1、BRITISH STANDARD Characteristics of DVB receivers The European Standard EN 50256 1998 has the status of a British Standard ICs 33.160.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 50256:1998 BS EN 50256:1998 direction of the Electrotechnical Sector Committee, was pu
2、blished under the authority of the Standards Committee and comes into effect on 15 December 1998 hd. No. National foreword Da Text affected This British Standard is the English language version of EN 50256A998. The UK participation in its preparation was entrusted by Technical Committee EPL 100, Aud
3、io, video and multimedia systems and equipment, to Subcommittee EPL 100/1, Radio receiving equipment, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the - monitor related international and European development
4、s and promulgate interpretation, or proposais for change, and keep the UK interests informed; them in the UK 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 publicat
5、ions referred to in this document 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 provisi
6、ons of a contract. Users of British Stan- 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, the EN title page, pages 2 to 5 and a
7、back cover. O BSI 1998 I l ISBN O 580 30397 7 - STD-BSI BS EN 5025b-ENGL 1998 I Lb24bb9 074L5L5 9TT D EUROPEAN STANDARD NORAD3 E;uROPEE”E EUROP- NOFW EN 50256 April 1998 Descriptors: television systems, television broadcasting, digital technics, television receivers, decoders, television by satellit
8、e, cable television, specifications English version Charack however, experiments in SECAM environments resulted in an optimum value of 8 dB. In the foliowing, a value of 10 dB is provisionally considered. Input level range Adjacent channel requirements 47 dB(pV) to 67 dB(p,V) Adjacent channel recept
9、ion in PAL or SECAM or igital environment is possible. The level of the adJacent digital channel can be 3 dF3 higher and the level of the axent analogue channel can be 13 dF3 higher than the level of the wanted digital channel (Ilus specification will be superseded if an appropriate amendment of EN
10、55020 is accepted) NOTE In the case of a back-off value of 10 dB, the carrier-to-noise ratio for digital signals in cable systems according to EN 50083-7, is 31 dB minimum (noise in 8 MHz bandwidth). Noise figure Under consideration Return loss Under consideration 4.2.2 Demodulator parameters The de
11、modulator shall be compatible with ETS 300 429. 4.3 Terrestrial COFDM receiver This section is under consideration. 5 WEG-2, systems, video and audio decoding The functionality of the receiver/decoder shall be compliant with ETR 154. 6 Functions and interfaces (See also EN 50201.) The application of
12、 the interfaces is optionai. 6.1 Interaction channel 6.1.1 Internal telephone modem Standards Dialling DTM or pulse Connector RT-45, see EN 50049-1 for analogue audio signais on pentelevision connectors, and EN 61938 for other audio signais. 7 Conditional access interface interface is specified in E
13、N 50221. O BSI 1998 BS EN 502561998 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Roya
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