Page 440 - Satellite Communications, Fourth Edition

420 Chapter Thirteen

at the receiving antenna, assuming 6-dB polarization discrimination. The
sidelobe gain function for the earth-station antenna is 32 25 log
.

13.10. A satellite circuit operates with an earth-station transmit power of 30
dBW and a satellite [EIRP] of 34 dBW. This circuit causes interference with a
neighboring circuit for which the earth-station transmit power is 24 dBW, the
transmit antenna gain is 54 dB, the satellite [EIRP] is 34 dBW, and the receive
earth-station antenna gain is 44 dB. Calculate the carrier-to-interference ratio
at the receive station antenna. Antenna sidelobe characteristics of 32 25 log

dB may be assumed, with the satellites spaced at 2° and polarization isolation
of 4 dB on uplink and downlink.

13.11. Repeat Prob. 13.10 for a sidelobe pattern of 29 25 log
.
13.12. A satellite TV/FM circuit operates with an uplink power of 30 dBW, an
antenna gain of 53.5 dB, and a satellite [EIRP] of 34 dBW. The destination earth
station has a receiver antenna gain of 44 dB. An interfering circuit has an uplink
power of 11.5 dBW and a satellite [EIRP] of 15.7 dBW. Given that the spectral
overlap is [Q] 3.8 dB, calculate the passband [C/I] ratio. Assume polarization
discrimination figures of 4 dB on the uplink and 0 dB on the downlink and an
antenna sidelobe pattern of 32 25 log
. The satellite spacing is 2°.

13.13. Repeat Prob. 13.12 for an interfering carrier for which the uplink
transmit power is 26 dBW, the satellite [EIRP] is 35.7 dBW, and the spectral
overlap figure is 3.36 dB.

13.14. An FDM/FM satellite circuit operates with an uplink transmit power of
11.9 dBW, an antenna gain of 53.5 dB, and a satellite [EIRP] of 19.1 dBW. The
destination earth station has an antenna gain of 50.5 dB. A TV/FM interfering
circuit operates with an uplink transmit power of 28.3 dBW and a satellite
[EIRP] of 35 dBW. Polarization discrimination figures are 6 dB on the uplink and
0 dB on the downlink. Given that the receiver transfer characteristic for wanted
and interfering signals is [RTC] 60.83 dB, calculate the baseband [S/I] ratio
for an antenna sidelobe pattern of 29 25 log
. The satellite spacing is 2°.

13.15. Repeat Prob. 13.14 for an interfering circuit operating with an uplink
transmit power of 27 dBW, a satellite [EIRP] of 34.2 dBW, and [RTC] 37.94 dB.

13.16. Explain what is meant by single-entry interference objectives. Show that
an interference level of 600 pW0p is equivalent to an [S/I ] ratio of 62.2 dB.
13.17. For the wanted circuit in Probs. 13.12 and 13.13, the specified
interference objective is [C/I ] pb 22 dB. Is this objective met?

13.18. For broadcast TV/FM, the permissible video-to-noise objective is specified
as [S/N] 53 dB. The CCIR recommendation for interference is that the total
interference from all other satellite networks should not exceed 10 percent of the
video noise and that the single-entry interference should not exceed 40 percent
of this total. Show that this results in a single-entry objective of [S/I ] 67 dB.