ISSN:0737-2884    

DOI:10.1002/sat.4600020402

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe attractive properties of the digital constant amplitude modulation scheme CPM (continuous phase modulation) have been demonstrated in a previous paper in this journal.1This concerned both the power and spectral efficiency of the large family of CPM schemes over the Gaussian channel.In this paper the considered channel can be both bandlimited or band‐ and amplitude‐limited at the same time. Analytical results as well as simulations are presented for a number of selected CPM schemes.In today's increasing demand for bandwidth, CPM is an attractive candidate for future satellite applications because of its spectral efficiency. In addition to this comes the fact that the transmitted signal has a constant amplitude and good detection performance when optimal coherent detection is perfor

ISSN:0737-2884    

DOI:10.1002/sat.4600020403

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

年代:1984

数据来源: WILEY

摘要:

AbstractWithout any doubt the geostationary orbit is for many applications the most suitable orbit because of the apparent standstill of its satellites. Unfortunately geostationary satellites cannot illuminate the polar regions and furthermore the number of orbit positions is limited. With satellites on certain, dependent on the system, circular or elliptical orbits inclined against the equatorial plane, it is possible to form, off the geostationary orbit, loop‐shaped quasi‐positions—referred to as Loopus positions—which are served by satellites of alternate identity. The basic idea is to employ in shift several satellites along the same apparent track which, in the alternate play with the earth's rotation, form small loops at the celestial sphere. Change‐over takes place at the loop intersection point where a collision of the two satellites is just avoided. Thus a system with for example three satellites, which serve two Loopus positions, allows uninterrupted (quasi‐)stationary communication via earth‐stations in two c

ISSN:0737-2884    

DOI:10.1002/sat.4600020404

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

年代:1984

数据来源: WILEY

摘要:

AbstractCarrier compression and third order intermodulation products of two and three unequal carriers have been studied experimentally using a 36 MHz wide C‐band transponder of INSAT‐1B satellite. From the experimental data, empirical relations for carrier compression for two unequal carriers have been derived, which agree with the measured data within ±0.5 dB. The empirical relations for carrier compression derived for two unequal carriers have been extended to three unequal carriers and good correlations with measured data have been obtained. Empirical relations for third order intermodulation products of two and three (f1+f2‐f3type) unequal carriers have also been d

ISSN:0737-2884    

DOI:10.1002/sat.4600020405

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

年代:1984

数据来源: WILEY

摘要:

AbstractElliptical antenna beams are used for planning of direct broadcast satellite systems. In this paper concepts of the beam optimization process are described briefly. A method of plotting the optimized beam on a suitable map projection is discussed. An interactive computer program, which can be used for the optimization and plotting of beams on a given territory, is described with the help of examples.

ISSN:0737-2884    

DOI:10.1002/sat.4600020406

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

年代:1984

数据来源: WILEY

摘要:

AbstractA Ku‐band satellite transponder capacity is evaluated for a PCM/QPSK/FDMA system in which many carriers are transmitted in an SCPC mode. The capacity depends on earth‐station sizes, error‐correction coding, required signal‐to‐noise ratio and required availability in rain; for simplicity all of these parameters are assumed to be the same for all carriers in the transponder. A method of accounting for the effects of rain is developed; it is assumed that the earth‐stations do not adjust their output power when it rains. Trade‐offs between earth‐station sizes and error‐correction code r

ISSN:0737-2884    

DOI:10.1002/sat.4600020407

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

年代:1984

数据来源: WILEY

摘要:

AbstractIn this paper, the INTELSAT SPADE system is re‐examined after 10 years of operation in the Atlantic Ocean Region. A functional description of the system is provided together with its technical evolution from the early years of development to the current maturity. Network monitoring and control, together with a summary of the SPADE System's activity from its traffic statistics and billing information are also discussed. Finally, it is shown that SPADE has fully met its original purpose and, based on the continuing high usuage of the SPADE system and the availability of a new generation SPADE terminal, SPADE will continue to be an important service for many years to com

ISSN:0737-2884    

DOI:10.1002/sat.4600020408

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

年代:1984

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600020409

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

年代:1984

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600020410

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

年代:1984

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600020411

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

年代:1984

数据来源: WILEY