INTERNATIONAL TELECOMMUNICATION UNION RADIOCOMMUNICATION BUREAU (Direct Fax No. +41 22 730 57 85) Administrative Circular 10 April 1994 CAR/8 TO THE ADMINISTRATIONS OF MEMBERS OF THE ITU Proposed approval of 8 draft new and revised Recommendations adopted by Radiocommunication Study Group 10 at its meeting from 28 February to 3 March 1994 At the meeting of Radiocommunication Study Group 10 (Broadcasting service (sound)), held from 28 February to 3 March 1994, the Study Group unanimously adopted the texts of 8 draft new and revised Recommendations, and agreed to apply the procedure of Resolution ITU-R 1 (see § 10) for approval of Recommendations between Radiocommunication Assemblies. The titles of these Recommendations are given in Annex. Having regard to the provisions of § 10.4.1 of Resolution ITU-R 1, I should be grateful if you would inform me by 10 July 1994, whether your Administration approves or does not approve these draft Recommendations. A Member who indicates that a draft new Recommendation should not be approved is requested to advise the reason and indicate possible changes in order to facilitate further consideration by the Study Group during the study period. After the above-mentioned deadline, the Director of the Radiocommunication Bureau will notify the results of this consultation by administrative circular and make arrangements for the Recommendations to be published in accordance with Resolution ITU-R 1. Richard C. KIRBY Director Annex: List of documents with titles Documents attached: Documents 10/BL/15 to 10/BL/22 Distribution: Administrations of Members of the ITU ANNEX List of titles of the 8 draft new and revised Recommendations adopted by Radiocommunication Study Group 10 (Geneva, 28 February to 3 March 1994) 1) Draft new Recommendations Draft new Recommendation ITU-R BS.[Doc.10/52(Rev.1)] 10/BL/15 LOW BIT-RATE AUDIO CODING This Recommendation specifies that for digital sound broadcasting emissions, contribution and distribution links and commentary links, the digital audio coding schemes described in ISO/IEC 11172-3, 1993 should be used. Layer III coding will apply to commentary links with bit rate of at least 60 kbit/s whilst layer II coding will apply to emission, distribution and contribution links. Draft new Recommendation ITU-R BS.[Doc. 10/65] 10/BL/18 METHODS FOR THE SUBJECTIVE ASSESSMENT OF SMALL IMPAIRMENTS IN AUDIO SYSTEMS INCLUDING MULTI-CHANNEL SOUND SYSTEMS This new Recommendation recommends procedures for testing, evaluating and documenting the subjective assessment of audio systems presenting small impairments such as those systems based on digital techniques exploiting psychoacoustic properties. The comprehensive set of procedures ranges from the selection of the listening panel to the programme material and listening conditions. Draft new Recommendation ITU-R BS.[Doc. 10/76(Rev.1)] 10/BL/19 SYSTEM FOR TERRESTRIAL DIGITAL SOUND BROADCASTING TO VEHICULAR, PORTABLE AND FIXED RECEIVERS IN THE FREQUENCY RANGE 30-3 000 MHz This Recommendation recognizing the need of a single worldwide standard for DAB, recommends a time frame to reach a final consensus on a draft new Recommendation on digital sound broadcasting systems and advises administrations to use digital system A for early implementation of terrestrial digital sound broadcasting services. 2) Draft revised Recommendations Draft Revision of Recommendation ITU-R BS.412-5 [Doc. 10/77]10/L B/20 PLANNING STANDARDS FOR FM SOUND BROADCASTING AT VHF The revision of this Recommendation consists of the inclusion of former Report 1064 as Annex 2 (particular interference cases in FM broadcasting) and the addition of a new Annex 3 dealing with the protection ratios for FM sound broadcasting in the case of the same programme and synchronized signals. Draft Revision of Recommendation ITU-R BS.640-1 [Doc. 10/58]10/B L/16 SINGLE SIDEBAND (SSB) SYSTEM FOR HF BROADCASTING The amendment to this Recommendation proposes a degree of suppression of the unwanted sideband of at least 25 dB where a carrier level of -6 dB relative to p.e.p. is used during the SSB transition period. Draft Revision of Recommendation ITU-R BS.707 [Doc. 10/78]10/BL/21 TRANSMISSION OF MULTI-SOUND IN TERRESTRIAL TELEVISION SYSTEMS PAL B, G, H AND I, AND SECAM L This Recommendation has been amended to extend to SECAM system L the recommended use of the NICAM 728 system for digital multisound associated to terrestrial TV emissions. Draft Revision of Recommendation ITU-R BS.774 [Doc. 10/79]10/BL/22 DIGITAL SOUND BROADCASTING TO VEHICULAR, PORTABLE AND FIXED RECEIVERS USING TERRESTRIAL TRANSMITTERS IN THE VHF/UHF BANDS The revision to this Recommendation includes two new considerings stressing that sound broadcasting has always used similar modulation techniques throughout the world and similar, if not identical, frequency bands leading to a receiver that could be used worldwide and recognizing that extensive broadcasting services provide programmes throughout the world. Draft Revision of Recommendation ITU-R BS.775 [Doc. 10/63]10/BL/17 MULTI-CHANNEL STEREOPHONIC SOUND SYSTEM WITH AND WITHOUT ACCOMPANYING PICTURE The revision of this Recommendation includes changes to the reference loudspeaker arrangement and a number of notes added to better define the reference listening test conditions. __________