Info Kxx
a\X\ |Y| \Z| format should be interpreted as follows: X values refer to System M (NTSC); Y values refer to Systems B, C, G, and H (PAL); and Z values refer to Systems D, K, and L (SECAM). All video signal-to-weighted noise ratios are calculated with weighting plus de-emphasis factors based on the unified weighting network (Rec. ITU-R CMTT.567-3), which has a noise bandwidth of 5 MHz for all TV systems.
b Excluding the maximum peak-to-peak deviation of 1 MHz due to the application of energy dispersal waveform.
cPeak frequency deviation of TV/FM carrier due to a 1.0-V peak-to-peak test tone at the crossover frequency of the pre-emphasis characteristic (excluding the maximum peak-to-peak deviation of 1 MHz due to the application of energy dispersal waveform).
d"A(P)"denotes previous Standard A earth station (G/T > 40.7 dB/K), and "A(R)" denotes revised Standard A earth station (G/T > 35.0 dB/K). "A" denotes either "A(P)"or "A(R)." eIf 22.5-MHz IF noise bandwidth is used in place of 30.0-MHz filters, the C/N value will be improved by about 1.2 dB.
fThe amount of overdeviation (OD) is defined as:
where Aftt = peak frequency deviation (in MHz) of TV/FM carrier due to 1.0-V peak-to-peak test tone at the crossover frequency of pre-emphasis characteristic, and Afcr = peak frequency deviation (in MHz) of the TV/FM carrier if it were designed to exactly match the receive filter bandwidth based on Carson's rule, Afcr = 1BIF - fm. Note that BIF is the receive IF bandwidth (in MHz) and fm is the maximum video bandwidth (in MHz). Source: INTELSAT IESS-306 (Rev. 3), Annex C (Ref. 26).
Figure 6.21. INTELSAT VII Atlantic 307.0° East satellite, expected antenna beam coverage for hemispheric, zone, and spot beams. Note: This satellite antenna coverage diagram illustrates the preliminary spacecraft platform pointing bias and spot beam pointing for this location. After the final pointing is selected, it or an appropriate pointing range will be used when determining the satellite antenna pattern advantage (Beta Factor) for each earth station as described in IESS-402. (The C-band spot beams are congruent.) The nominal beam edge contours are illustrated: □, subsatellite point; and ©, satellite antenna platform. Pointing bias = 1.90° East; yaw bias = 0°. It should be noted that INTELSAT uses a nonconventional 360° longitude scheme for identifying subsatellite points. (Figure and note are from INTELSAT IESS-409, Figure 7; Ref. 18.)
Figure 6.21. INTELSAT VII Atlantic 307.0° East satellite, expected antenna beam coverage for hemispheric, zone, and spot beams. Note: This satellite antenna coverage diagram illustrates the preliminary spacecraft platform pointing bias and spot beam pointing for this location. After the final pointing is selected, it or an appropriate pointing range will be used when determining the satellite antenna pattern advantage (Beta Factor) for each earth station as described in IESS-402. (The C-band spot beams are congruent.) The nominal beam edge contours are illustrated: □, subsatellite point; and ©, satellite antenna platform. Pointing bias = 1.90° East; yaw bias = 0°. It should be noted that INTELSAT uses a nonconventional 360° longitude scheme for identifying subsatellite points. (Figure and note are from INTELSAT IESS-409, Figure 7; Ref. 18.)
6.6 DOMESTIC AND REGIONAL SATELLITE SYSTEMS 6.6.1 Introduction
Domestic and regional satellite communication systems are attractive to regions of the world with a large community of interest. These regions may be just one country with a comparatively large geographical expanse, such as the United States, India, Brazil, Indonesia, Australia, Japan, Mexico, and Russia, or a group of countries with a common interest, such as Europe, or a common culture, such as the Arabic-speaking countries, or a common language, such as Hispanic America. Many of these systems also serve areas that are sparsely populated to deliver quality telephone/data service and TV programming. Canada's ANIK/TeleSat is a good example. Still another family of systems serves the business community, providing basically a digital offering. One important group of this type provides long-distance enterprise networking. In this case, the "enterprise" leases all or part of one or more satellite transponders. VSAT (very small aperture terminal) systems are in this category. They are really burgeoning in many parts of the world. VSAT systems are described in Chapter 8.
About three-quarters of the transponder space, particularly in the Ku-band, over North America supply TV programming to CATV headends and for hotels and motels.
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