摘要:

AbstractThis paper addresses the question of integrating satellites within the ISDN, concentrating on PSTN application. After a brief look at the role satellites have played to date in international telecommunications, and the new environment that ISDN will bring, an examination is made of the work done by CCITT on the transmission aspects of ISDN. This is followed by a look at the main features of digital satellite systems at the present time, including transmission performance as defined by CCIR, and a critical comparison is made with ISDN requirements including an indication of how error performance may need improving. The paper concludes with a discussion of how satellite system operators might respond to the demands of the ISDN.

ISSN:0737-2884    

DOI:10.1002/sat.4600010202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper reviews two TDMA systems which have been developed at NTT (Nippon Telegraph and Telephone Public Corporation) for domestic use in Japan.The first system uses K‐Bands (30/20 GHz) and is called the TDMA‐65M system. This system constructs a variable channel capacity network between 8 major cities (regional centres).The second system uses C‐Bands (6/4 GHz) and is called the TDMA‐100M system. This system provides remote island communication links for simultaneous transmission of voice and colour television signals.These two TDMA systems were put into commercial operation in summer 1983 by using, respectively, the Communication Satellite‐2s, CS‐2a which was launched in February 1983 and CS‐2b which was launched i

ISSN:0737-2884    

DOI:10.1002/sat.4600010203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper is the second of a four‐part series addressing the testing and alignment techniques to be used in the INTELSAT TDMA/DSI system. In the first part,1the salient characteristics of the overall TDMA/DSI system were presented, together with a discussion of the fundamental requirements for testing and alignment. In this second part, INTELSAT's satellite system operations guide (SSOG) for TDMA is introduced and the principles of testing embodied in the SSOG tests are discussed. In particular, the impact of the unique TDMA access discipline on testing is examined. The third part will address the design of the specialized test equipment required. The fourth part will complete the series with a report on the operational experience gained in the initial stages of the TDMA implementation within the INTELSAT syste

ISSN:0737-2884    

DOI:10.1002/sat.4600010204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper describes the basic control features of a typical satellite switch system, such as INTELSAT VI. Factors are addressed pertaining to the data format that is used to express the switch plan, the timing control of the switch states comprising the satellite switch frame, the transmission of the switch plan to the satellite, storage and execution of the switch plan on board, and the coding of switch plan data for protection from radiation‐induced bit errors. Also, the implementation used to achieve precision control of the on‐board clock is discussed, and the influence of clock control variation on all the terrestrial interfaces that participate in the system is demonstrated. Finally, the method for achieving network‐wide coordinated switch state time plan/TDMA burst time plan changes, which are essential in an operational satellite‐switched (SS)‐TDMA system, is

ISSN:0737-2884    

DOI:10.1002/sat.4600010205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper describes the performance of various voice encoding techniques at 32 and 16 kb/s for applying to digital satellite communication systems. The subjective performances of adaptive differential PCM (ADPCM), adaptive predictive coding (APC), subband coding (SBC) and adaptive delta modulation (ADM) are compared under various satellite channel environments, that is, random and burst channel errors in satellite link and an ambient noise in the ship‐to‐shore direction in a maritime satellite channel. The performance of the voiceband data at 4·8 and 2·4 kb/s is also evaluated for these coders. ADPCM encoding at 32 kb/s is very attractive for conventional fixed satellite systems, keeping the equivalent quality to 64 kb/s PCM. On the other hand, APC encoding at 16 kb/s is also most suitable for maritime satellite communication systems at the sacrifice of a small degradation of speech qu

ISSN:0737-2884    

DOI:10.1002/sat.4600010206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA new standard of INMARSAT ship earth station for multi‐channel operation could find particular application on large passenger ships and off‐shore oil/gas platforms. This paper provides estimates of platform and ship motions and discusses general design requirements, notably of the antenna system. The discussion includes consideration of possible modulation and multiple access techniques. Single channel per carrier (SCPC) operation is advocated which permits easy integration with the present service to single channel INMARSAT Standard‐A ship earth stations. Major parameter/relative cost trade‐off curves needed in an overall ship earth station design optimization are pr

ISSN:0737-2884    

DOI:10.1002/sat.4600010207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe paper describes a new adaptive tracking system which, unlike simple step‐track sytems, does not use the stepping cycles to directly position the antenna. The system can cope with severe noise; about 15 dB worse than step track. The system is cheap and practical. Results are given for both large and small dish antenna

ISSN:0737-2884    

DOI:10.1002/sat.4600010208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractIn the design of communication satellite systems, knowledge of earth‐station receive antenna gain and gain stability is essential. Gain measurement relies on the establishment of a constant receive signal flux.This paper attempts to show how a standard gain horn and a reference source can be used together with a closed‐loop satellite ALC circuit to provide a stable, known received flux at the input of the earth‐station antenna with unknown gain. Theoretical limitations of the technique are discussed as a forerunner to future practical measurements.Elements of the reference receive chain are transportable and can therefore be used to cross‐calibrate antennas, even in the case of receive‐only

ISSN:0737-2884    

DOI:10.1002/sat.4600010209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600010211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600010212

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY