Rec. Itu-r bo. 712-1




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Rec. ITU-R BO.712-1

RECOMMENDATION ITU-R BO.712-1*,**

High-quality sound/data standards for the broadcasting-satellite


service in the 12 GHz band

(1990-1992)


The ITU Radiocommunication Assembly,

considering

a) the needs expressed for the future development of satellite broadcasting both in the field of simultaneous transmission of a series of radio programmes of a very high technical quality and in the field of high-capacity data services;

b) the technical performance of the DSR (digital satellite radio) system which allows the transmission, in a channel of the 12 GHz band, of 16 stereophonic programmes of very high quality with maximum ruggedness against transmission errors;

c) the definition of the digital full-channel mode of operation of systems of the MAC/packet family which allows for flexible multiplexing (20 Mbit/s for systems C and D, 10 Mbit/s for the D2 system) of sound programmes of high quality as well as any type of data;

d) the technical flexibility of the MDS (multi-channel digital sound/data) system which allows not only the transmission of 12 high quality stereo programmes, but also in the case of lower e.i.r.p., the transmission of 6 high quality programmes with an additional error correction code;

e) that the MAC/packet system, the DSR system and the MDS system are intended for use via broadcasting satellites to fixed receivers;

f) that other systems are being developed for sound broadcasting at UHF to fixed, portable and especially to mobile receivers,

recommends

that when a sound/data broadcasting-satellite service to fixed receivers is introduced in the 12 GHz band the preferred systems should be (see Notes 1 and 2):

– the DSR system when the predominant consideration is the transmission of a number of very high-quality sound programmes within a wide coverage area;

– the full-channel digital mode of one of the systems of the MAC/packet family when the predominant consideration is the flexibility required for simultaneous transmission of high-quality sound programmes and high capacity data services;

– the MDS system when the predominant consideration is compatibility with the digital sub-carrier/NTSC system.
NOTE 1 – The issue of a sound/data standard for the broadcasting-satellite service is still under consideration in Region 2.

NOTE 2 – Detailed system descriptions are given in Annex 1.

NOTE 3 – The following guide is given to assist in following the relationship of the Annexes and Appendices.

ANNEX 1




APPENDIX 1 TO ANNEX 1







ANNEX 1 TO APPENDIX 1







ANNEX 2 TO APPENDIX 1







ANNEX 3 TO APPENDIX 1







ANNEX 4 TO APPENDIX 1







ANNEX 5 TO APPENDIX 1




APPENDIX 2 TO ANNEX 1




APPENDIX 3 TO ANNEX 1

ANNEX 1


High quality sound/data standards for the broadcasting-satellite
service in the 12 GHz band

1 Introduction


According to the current Radio Regulations, satellite channels in the 12 GHz band are assigned to each administration over which television programmes but also, alternatively, other services may be broadcast, as long as the transmitted signals do not cause more interference than conventional FM TV signals. The appropriate TV standards are recommended in Recommendation ITU-R BO.650 and specified in the relevant parts of the ITU-R special publication, “Specifications of Transmission Systems for the Broadcasting-Satellite Service”.

The introduction of digital sound recording and reproduction techniques constitutes a challenge to the broadcasting organizations to pass on such a quality to the subscribers which has been beyond the possibilities of conventional transmission methods (e.g. FM stereo). Besides this, in a number of countries there is a need for the emission of a large number of high-quality sound channels over a coverage area as large as possible. In addition, the growing requirements for data broadcast facilities resulted in investigations of systems suitable to transmit both sound and data in a flexible way.

Several possible systems are in various stages of development within different administrations. This Annex briefly describes the basic characteristics of three systems developed in the Federal Republic of Germany, by the EBU and in Japan.

2 Summary description of the systems


This section gives the summary description of the main features of each of the systems considered. Table 1 gives the list of relevant parameters of each system in a comparative way.
TABLE 1

Relevant parameters of satellite sound/data broadcasting
standards for the 12 GHz BSS band


Parameter

Digital satellite radio

MAC/packet family full-channel digital mode

Multi-channel digital sound/data




(DSR)

D2

C/D

satellite broadcasting (MDSD)

Multiplex structure

Synchronous time division multiplex
(STD)

Asynchronous time division multiplex
(ATD)

Sound: STD multiplex

Data: ATD multiplex



Total bit rate (Mbit/s)

20.48

10.125

20.252

24.576

MDS1 (2): 18.432 (Mode A)


21.504 (Mode B)

Useful bit rate (1) (Mbit/s)

19.22

09.576

19.242

MDS2 (2) : 9.216 (Mode A)
10.752 (Mode B)

Sound coding (3)

32 kHz sampling frequency

32 kHz sampling frequency (16 kHz for medium quality)

Mode A: 32 kHz sampling frequency 14/10 bit near-instantaneous companding




16/14 bit floating point technique

First coding law:
14/10 bit near-instantaneous compandor (HQI) (4)

Mode B: 48 kHz sampling frequency
16 bit linear coding







Second coding law:
14 bit linear coding (HQL)







No pre-emphasis

Pre-emphasis per ITU-T Recommendation J.17

Pre-emphasis:

50 s (zero)  15 s (pole)



Dynamic range

According to 16 bit resolution (equal to compact disk)

According to
14 bit resolution

Mode A: According to 14 bit resolution

Mode B: According to 16 bit resolution



Bit-error protection

BCH (63,44) code: corrects 2 errors in 63 bits or detects 5 errors. Additional protection by the scale factor

First protection level: 1 parity bit applied to the 6 MSB (HQI) or to the 10 MSB (HQL case) (error concealment only)

MDS1:

BCH (63,56) code: corrects 1 error and detects 2 errors. Additional protection by the 8 range information









Second protection level: Hamming code (11,6) for HQI and Hamming code (16,11) for HQL: corrects 1 error or detects 2 erroneous bits. Additional protection by scale factor for both protection levels

MDS2:

BCH (63,50) code: addition to the above, the whole data is protected


by (2,1) Viterbi decoding

Number of sound configurations (i.e. combination of sound coding and error protection scheme)

One (see above)

Four high quality

configurations (4), (5)

HQI1
HQL1
HQI2
HQL2


Two high quality configurations

Mode A


Mode B

TABLE 1 (continued)



Parameter

Digital satellite radio

MAC/packet family full-channel digital mode

Multi-channel digital sound/data




(DSR)

D2

C/D

satellite broadcasting (MDSD)

Sound channel capacity (monophonic)

32

HQI1: 26
HQL1: 19
HQI2: 19
HQL2: 14

HQI1: 53
HQL1: 40
HQI2: 40
HQL2: 30

MDS1: Mode A: 48 (maximum)
Mode B: 24 (maximum)

MDS2: Mode A: 24 (maximum)


Mode B: 12 (maximum)

Modulation

4-PSK differentially encoded

For D and D2: FM of duobinary coded data signal

For C: 2-4 PSK, differentially encoded



Minimum shift keying (MSK)



C/N for BER  10–3 (overall link with reference to 27 MHz bandwidth)

7.5 dB (6)

8 dB (7)

for D: 9.5 dB (7)

for C: 8.0 dB (8)



8.0 dB

Limit for perceptibility

2  10–3

1st level protection: 10–5

2nd level protection: 10–3



MDS1: 1  10–3

MDS2: 1  10–2



(1) Useful bit rate (for sound transmission) = total bit rate minus sync, additional data and packet headers.

(2) MDS1: a transmission class for a sufficient e.i.r.p. receiving condition.
MDS2: a transmission class for a lower e.i.r.p. receiving condition.

(3) All coding schemes used follow Recommendation ITU-R BO.651.

(4) HQI1 : High quality, near-instantaneous companding, 1st protection level
HQL1: High quality, linear coding, 1st protection level
HQI2 : High quality, near-instantaneous companding, 2nd protection level
HQL2: High quality, linear coding, 2nd protection level.

(5) In addition to high quality configurations, MAC/packet full-channel digital mode allows four medium quality configurations using 16 kHz sampling.

(6) Measured with a domestic receiver (first series of mass production).

(7) Values for 27 MHz IF filter; improvements of around 2 dB are possible by using narrower filters and/or applying Viterbi decoding.

(8) Typical value for differential demodulation. With coherent demodulation improvements are possible.


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