Page 441 - Satellite Communications, Fourth Edition

Interference 421

13.19. Explain what is meant by protection ratio. A TV/FM carrier operates at a
modulation index of 2.619, the top modulating frequency being 4.2 MHz. Calculate
the protection ratio required for quality factors of (a) 4.2 and (b) 4.5. How do these
values compare with the specified interference objective of [C/I] pb 22 dB?

13.20. Explain what is meant by energy dispersal and how this may be achieved.

13.21. Explain what is meant by coordination in connection with interference
assessment in satellite circuits.

References

CCIR Recommendation 523. 1978. “Maximum Permissible Levels of Interference in a
Geostationary Satellite Network in the Fixed Satellite Service Using 8-bit PCM
Encoded Telephony Caused by Other Networks of This Service.” 14th Plenary
Assembly, Vol. IV, Kyoto.
CCIR Report 391-3. 1978. “Radiation Diagrams of Antennae for Earth Stations in the Fixed
Satellite Service for Use in Interference Studies and for the Determination of a Design
Objective.” 14th Plenary Assembly, Vol. IV, Kyoto.
CCIR Report 454-3. 1982. “Method of Calculation to Determine Whether Two Geostationary-
Satellite Systems Require Coordination.” 15th Plenary Assembly, Vol. IX, Part 1, Geneva.
CCIR Report 634-2. 1982. “Maximum Interference Protection Ratio for Planning Television
Broadcast Systems.” Broadcast Satellite Service (Sound and Television), Vols. X and
IX, Part 2, Geneva.
Chouinard, G. 1984. “The Implications of Satellite Spacing on TVRO Antennas and DBS
Systems.” Canadian Satellite User Conference, Ottawa.
ITU. 1985. Handbook on Satellite Communications (FSS). Geneva.
ITU. 1986. Radio Regulations. Geneva.
Jeruchim, M. C., and D. A. Kane. 1970. Orbit/Spectrum Utilization Study, Vol. IV. General
Electric Doc. No. 70SD4293, December 31.
Microwave Filter Company, Inc. 1984. “TI and TVROs: A Brief Troubleshooting Guide to
Suppressing Terrestrial Interference at 3.7–4.2 GHz TVRO Earth Stations.”
Sharp, G. L. 1983. Reduced Domestic Satellite Orbital Spacings at 4/6 GHz. FCC/OST
R83-2, May.
Sharp, G. L. 1984a. “Reduced Domestic Satellite Orbit Spacing.” AIAA Communications
Satellite Systems Conference, Orlando, FL, March 18–22.