1、 CEA Bulletin BTSC System Multichannel Television Sound Recommended Practices CEA-TVSB-5 R-2011 March 2011 NOTICE Consumer Electronics Association (CEA ) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manu
2、facturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards, Bulletins and other technical publications shall not in any respec
3、t preclude any member or nonmember of CEA from manufacturing or selling products not conforming to such Standards, Bulletins or other technical publications, nor shall the existence of such Standards, Bulletins and other technical publications preclude their voluntary use by those other than CEA mem
4、bers, whether the bulletin is to be used either domestically or internationally. Standards, Bulletins and other technical publications are adopted by CEA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, CEA does not assume any liability to any patent
5、 owner, nor does it assume any obligation whatever to parties adopting the Standard, Bulletin or other technical publication. This CEA Bulletin is considered to have International Standardization implication, but the International Electrotechnical Commission activity has not progressed to the point
6、where a valid comparison between the CEA Bulletin and the IEC document can be made. This Bulletin does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Bulletin to establish appropriate safety a
7、nd health practices and to determine the applicability of regulatory limitations before its use. This document is copyrighted by the Consumer Electronics Association (CEA) and may not be reproduced, in whole or part, without written permission. Federal copyright law prohibits unauthorized reproducti
8、on of this document by any means. Organizations may obtain permission to reproduce a limited number of copies by entering into a license agreement with IHS (http:/). .Requests to reproduce text, data, charts, figures or other material should be made to the CEA. (Formulated under the cognizance of th
9、e CEA R4 Video Systems Committee.) Published by CONSUMER ELECTRONICS ASSOCIATION 2011 Technology L.B.Tyler. C. RF transmission and antenna considerations; J.J. Gibson. D. Relations between amplitudes and phases of the stereophonic difference encoded signal “D“ and the stereophonic sum modulating sig
10、nal “M“ in the BTSC system when a sinewave feeds the left input; J.J. Gibson. E. A companding system for multichannel sound (A tutorial on companding); L.B.Tyler, et al. IEEE Transaction on Consumer Electronics, November 1984, Volume CE-30, Number 4. Reproduced with permission. F. Filter requirement
11、s in TV multichannel sound; Pieter Fockens. G. Aural carrier deviation by composite stereo -need for calibration; Pieter Fockens. H. Pilot protection in the BTSC system; Pieter Fockens. I. A proposed test signal for measuring crosstalk between subchannels; J.J. Gibson. J. BTSC companding programs -D
12、EBEX; J.J. Gibson. K. Calculations of expander noise reduction and noise pumping in the presence of signals; J.J. Gibson. 7 6. REFERENCES 1. EIA Multichannel Sound Reports Volume I, published by the National Association of Broadcasters, July 16, 1982. Volume l-A, published by the National Associatio
13、n of Broadcasters, November 9, 1983. Supplement to Volumes l-A and 2-A, published by Electronic Industries Association, December 5, 1983. Compandor Complexity Analyses, published by Electronic Industries Association, December 12, 1983. Zenith Separate Audio Program Generator; Multipath Buzz and Dist
14、ortion Investigation; Alpha-Omega Engineering, Inc. Statement, published by Electronic Industries Association, December 19, 1983. Volume 2, published by Electronic Industries Association, Consumer Electronics Group, August 6, 1982. Volume 2-A, published by Electronic Industries Association, November
15、 5, 1983. 2. Electrical performance standards for TV transmitters (To be published as EIA-508). 3. Recommended Practice for Audio Program Level Measurement (Draft in preparation by IEEE G 2.1.2, Audio Measurements Subcommittee). 4. Electrical Performance Standards for Television Broadcast Demodulato
16、rs, EIA RS-462 (May, 1979). 8 1. INTRODUCTION 1.1. Scope This document is intended to serve the industry in the form of recommendations for anyone wishing to practice multichannel television sound (MTS) in accordance with the BTSC system and the FCC Rules governing its use. Both the FCC Report and O
17、rder in Docket 21323 which authorized MTS, and the OST Bulletin No.60 (OST 60 gives a technical description of the BTSC system) referred to in that report are reproduced in Appendix A. This document is intended for equipment manufacturers and broadcasters. For manufacturers, there is discussion mate
18、rial useful to determine design tradeoffs together with recommended performance standards. For broadcasters, there is discussion and information, which allows individual equipment items to be defined in terms of performance so that the transmitter plant will perform properly as a system. Receiver is
19、sues are identified which are of particular significance to the broadcaster as well as to the receiver manufacturer. While there is herein much useful information for the CATV industry, this document does not directly address the CATV MTS application. 1.2 Description of the System and Its Protection
20、 The transmission standards are graphically illustrated in Figure 1.2.1 and summarized in Table 1.2. More detailed system standards are found in OST 60 and the total system block diagram in Figures 1.2.2 and 1.2.3. The main-channel aural-carrier modulation consists of an (L+R) audio signal. It is su
21、bjected to 75 us preemphasis. The (L-R) audio signal is subjected to compression (the transmitter part of the companding system that includes complementary expansion in the receiver). The compressed (L-R) signal causes double-sideband, suppressed-carrier amplitude modulation of a subcarrier at 2f Hw
22、here f H is the transmitted picture horizontal scanning frequency, 15.734 kHz. The audio bandlimits of both preemphasized (L+R) and of encoded (L-R) are 50 Hz and 15 kHz. The main channel peak deviation is 25 kHz. The stereophonic subchannel peak deviation is 50 kHz. When L and R are statistically i
23、ndependent, the combined peak deviation of the main channel and the stereophonic subchannel is also 50 kHz when full interleaving exists. When (L+R) and (L-R) signals do not have matching pre-emphasis characteristics (as is the case when (L-R) is compressed), the combined deviation of main channel a
24、nd stereophonic subchannel is constrained to 50 kHz. The separate components assume their respective natural levels as dictated by the acoustic scene. 9 10 11 12 Note in Table 1.2 that the listed 25 kHz main channel (monophonic) peak deviation is embedded in the 50 kHz (L-R) part of the 73 kHz total
25、 deviation due to the above-mentioned constraint. Therefore, the system is operated under two deviation constraints, 25 kHz for the main channel and 50 kHz for the combination of the main channel and the stereophonic subchannel, whichever deviation limit is reached first. A CW pilot subcarrier signa
26、l of frequency f His transmitted with a main carrier deviation of 5 kHz. The subcarrier for the second audio program (SAP) channel has a frequency of 5f H(78.670 kHz) and is frequency locked to 5f Hin the absence of modulation. The SAP audio signal is subjected to compression identical to that of th
27、e (L-R) signal. The resulting SAP modulating signal is bandlimited to 10 kHz and frequency modulates the SAP subcarrier to a peak deviation of 10 kHz. The professional subchannel has a subcarrier located at approximately 6.5 f Hand modulates the aural carrier by 3 kHz peak deviation. The protection
28、afforded the BTSC MTS system in the FCC rules (Section 73.682, C,3) is essentially one of allowing only the BTSC system to use a pilot of 15.734 kHz although no protection is afforded the second audio program (SAP). Furthermore, since the BTSC system as described in OST 60 is referred to in the rule
29、s, the system performance standards from OST 60 are essentially part of the FCC rules. 1.3 Definitions 1.3.1 Miscellaneous Definitions Visual demodulator -A device performing according to EIA Standard RS-462 (4) used for the measuring of a transmitters ICPM and visual modulating frequency characteri
30、stics. Aural carrier monitoring and measuring equipment - Equipment to monitor the aural radiated signal and to measure its desired and undesired characteristics; also serves to measure the potential visual-carrier related interference. BTSC companding -A noise reduction process used in the stereoph
31、onic subchannel and in the second audio program subchannel consisting of compression (encoding) before transmission and complementary expansion (decoding) after reception. (This definition conforms to “compandoring“ in OST 60 Section A). BTSC stereo audio processor -The processor that accepts L and R audio input signals and delivers the stereophonic 13
