1、6 ITU-R RECMN*SNG* 1152 75 m 4855232 0525762 T8b m Rec. ITU-R SNG.1152 RECOMMENDATION ITU-R SNG. 1 152 USE OF DIGITAL TRANSMISSION TECHNIQUES FOR SATELLITE NEWS GATHERING (SNG) (SOUND) (Question -R 227/4) (1995) The ITU Radiocommunication Assembly, considering that the very nature of Satellite News
2、Gathering (SNG) requires that earth stations are used for short periods of that highly portable transmitlreceive stations are essential for sound news gathering operations under that low bit rate coding methods, such as ISO/IEC 11 172-3 layers II and III, are already defined that provide that these
3、stations could provide data communications for exchange of text; that technologies exist that could provide this service, a) time and for specific news gathering purposes and hence must be activated in an expedient manner; b) conditions where other forms of communications of the needed quality are n
4、ot readily available; cl various levels of audio quality for sound news gathering; d) e) further considering f) that single channel per carrier (SCPC) transmitting equipment offers a possibility for SNG (sound) on satellites in the FSS bands; g) that some equipment and services for SNG (sound) purpo
5、ses are already used in the mobile-satellite service (MSS) bands under special license from some administrations (e.g. INMARSAT-A, INMARSAT-B and INMARSAT-M systems); h) that technology is advancing rapidly in the area of sound encoding techniques, permitting higher quality sound at reduced bit rate
6、s; j) that further studies are needed to develop uniform technical standards for digital SNG (sound) earth station transmission and to investigate issues, such as cascading of codecs, recommends 1 indicated in Annex 1. that the services and equipments used for SNG (sound) purposes should have the ge
7、neral characteristics as ITU-R RECMNrSNG. 1152 95 q55212 05257b3 712 Rec. ITU-R SNG.1152 ANNEX 1 General characteristics of SNG (sound) systems 7 SNG (sound) should have the following general characteristics: Technical attributes Audio quality: Range of systems from a “minimum-level-of-service” syst
8、em providing acceptable voice-only audio quality to a “full-level-of-service” system providing feeds of remote concerts with CD-quality stereo audio. Znteroperability: All systems of a specified “level-of-service” shall interoperate. Standards: Use internationally recognized standards. Coordination:
9、 Provides two-way communications to coordinate the feeds. Other services: Supports transmission of fax and data. Maintainability: Self-testing, maintainable by operator and soft fail modes of operation. Area of service: Can be used throughout the world including remote areas. Extension: Provides for
10、 graceful evolution to include new features and new technology and standards. Physical attributes Electrical characteristics: Operates on commercial power standards throughout the world. Operates with battery C) voltages for several hours. Environmental characteristics: Operates in temperatures of -25 “C to +55 “C and humidity of 95% non-condensing at 40 OC. Tolerant of dust and shocks. Size and weight: Transportable by one individual for a “minimum-level-of-service” system or by no more than two individuals for a “full-level-of-service” system.
