ITU-R BS 707-5-2005 Transmission of multisound in terrestrial television systems PAL B B1 D1 G H and I and SECAM D K K1 and L《地面电视系统PAL B、B1、D1、G、H 和I、以及SECAM D、K、K1和L中的多音传输》.pdf
《ITU-R BS 707-5-2005 Transmission of multisound in terrestrial television systems PAL B B1 D1 G H and I and SECAM D K K1 and L《地面电视系统PAL B、B1、D1、G、H 和I、以及SECAM D、K、K1和L中的多音传输》.pdf》由会员分享,可在线阅读,更多相关《ITU-R BS 707-5-2005 Transmission of multisound in terrestrial television systems PAL B B1 D1 G H and I and SECAM D K K1 and L《地面电视系统PAL B、B1、D1、G、H 和I、以及SECAM D、K、K1和L中的多音传输》.pdf(7页珍藏版)》请在麦多课文档分享上搜索。
1、 Rec. ITU-R BS.707-5 1 RECOMMENDATION ITU-R BS.707-5*,*Transmission of multisound in terrestrial television systems PAL B, B1 D1, G, H and I, and SECAM D, K, K1 and L (1990-1994-1995-1998-2005) Scope This Recommendation provides systems specifications for television multisound. The ITU Radiocommunic
2、ation Assembly, considering a) the increasing requirement worldwide for suitable means of broadcasting stereophonic and/or multichannel sound and/or data from terrestrial television transmitters; b) the technical developments in this area and in particular the relative merits of various possible ana
3、logue and digital methods, as described in Report ITU-R BS.795; c) the improvements in television sound quality achieved with recent developments of equipment used for the transmission and reception of the two sound-carrier FM system; d) the improvements in television sound quality achieved with the
4、 NICAM-728 system using digital coding; e) Recommendation ITU-R BO.651 concerning “Digital PCM coding for the emission of high-quality sound signals in satellite broadcasting (15 kHz nominal bandwidth)”; f) Recommendation ITU-R BO.650 concerning the adoption of MAC/packet systems for satellite broad
5、casting in channels defined by the World Administrative Radio Conference for the Planning of the Broadcasting-Satellite Service (Geneva, 1977) (WARC BS-77) and the desirability of a close measure of commonality between digital systems for satellite and terrestrial broadcasting; g) the advantage of l
6、ow-cost analogue circuitry for multisound television receivers for the two sound-carrier FM system; h) the development of digital audio circuitry for other applications in the home; j) the ruggedness of the two sound-carrier FM system in difficult reception areas especially under multipath reception
7、 conditions and its excellent compatibility with existing receivers, transmitters, networks and services, including the case of 7 MHz channel spacing; k) the need to use a digital sound system in television that satisfies simultaneously and with a generous margin, the contradictory constraints of: r
8、uggedness in difficult reception areas, including the requirement for failure of sound after vision, and *This Recommendation should be brought to the attention of the International Electrotechnical Commission (IEC). *Radiocommunication Study Group 6 made editorial amendments to this Recommendation
9、in 2002 in accordance with Resolution ITU-R 44. 2 Rec. ITU-R BS.707-5 compatibility between the new and existing services, including the case of 7 MHz channel spacing; l) the fact that the two sound-carrier FM system was introduced to the ex-CCIR in 1974, became operational in 1981, and is now in ex
10、tensive use in the Federal Republic of Germany and in various other countries; m) the fact that the NICAM-728 system was introduced to the ex-CCIR in 1987, became operational in 1988, is now in extensive use in Finland, Sweden, Denmark, Norway, New Zealand and the United Kingdom and is planned for i
11、ntroduction in various other countries; n) the urgency of establishing unified standards in order to provide for the introduction of stereophonic and/or multichannel sound for the television broadcast services, recommends 1 that if analogue multisound is introduced in terrestrial television emission
12、s in countries using PAL television systems B, B1, G and H, the two sound-carrier FM system, as defined in Annex 1 should be used; 2 that if digital multisound is introduced in terrestrial television emissions in countries using PAL television systems B, B1, D1, G, H and I, and SECAM television syst
13、ems D, K, K1 and L, the system specified in Annex 2 should be used. NOTE 1 Studies are continuing to define multisound system parameters to be recommended for other television systems. NOTE 2 The transmission systems described can, in some cases, be used for data services. Where applicable, referenc
14、e to these data services will be found in the Annexes containing the system specifications. NOTE 3 Interference caused by multisound emission to other television systems is dealt with in Report ITU-R BT.1214. Annex 1 System specifications for the two sound-carrier FM system TABLE 1 Emission characte
15、ristics of the two sound-carrier FM system (Television systems B, B1, G and H) Characteristics Sound carrier 1 Sound carrier 2 RF-sound carriers Frequency referred to vision carrier (MHz) 5.5(1)5.5 0.2421875(1)Power referred to peak vision (dB) 13 20 Modulation MF MF Frequency deviation (kHz) 50 50
16、Audio-bandwidth (Hz) 40 to 15 000 40 to 15 000 Pre-emphasis (s) 50 50 AF-signals Monophonic Monophonic 1 Monophonic 1 Stereophonic (A + B)/2 B Double sound Monophonic 1 Monophonic 2 Rec. ITU-R BS.707-5 3 TABLE 1 (end) Characteristics Sound carrier 1 Sound carrier 2 Identification signals(2)Subcarrie
17、r frequency (kHz) 54.6875(3)(3.5 line frequency) Modulation AM Modulation depth (%) 50(4)Modulation frequency:(3)(Hz) Monophonic 0 Stereophonic 117.5 (line frequency/133) Double sound 274.1 (line frequency/57) Frequency deviation of the second sound carrier by the subcarrier (kHz) 2.5 Audio-frequenc
18、y companding(5)Not yet defined (1)The frequency difference between both sound carriers is 15.5 line frequency = 242.1875 kHz. Phase-locking of both sound carriers with the line frequency gives improvements, but is not absolutely necessary. (2)Additional identification signals of the three sound mode
19、s may also be transmitted in the digital data line in the vertical blanking interval. (3)The subcarrier and identification frequencies are phase-locked with the line frequency. (4)The residual 50% AM modulation depth is reserved for future identification of audio-frequency companding. (5)The use of
20、a compatible audio companding system would improve the audio signal-to-noise ratio. Annex 2 Summary of the system specification for digital multisound with terrestrial television systems B, B1, G, H, I and L 1 Introduction The following is a summary of the specification of the systems for transmissi
21、on of digital multi-sound with terrestrial television systems B, B1, D1, D, G, H, I, K, K1 and L. 2 Frame format Frame length: 728 bits Frame transmission rate: 1 frame/ms 2.1 Frame structure Frame alignment word: 8 bits Control information: 5 bits Additional data: 11 bits Sound/data coding block: 7
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