1、Rec. ITU-R SA.514-3 1 RECOMMENDATION ITU-R SA.5 14-3 INTERFERENCE CRITERIA FOR COMMAND AND DATA TRANSMISSION SYSTEMS OPERATING IN THE EARTH EXPLORATION-SATELLITE AND METEOROLOGICAL-SATELLITE SERVICES (Questions ITU-R 139/7 and ITU-R 141/7) (1978-1990-1994-1997) The ITU Radiocommunication Assembly, c
2、onsidering 4 space-to-Earth links in some frequency bands; b) links in some frequency bands; that Recommendations ITU-R SA. 1026, ITU-R SA. 1160 and ITU-R SA. 1163 contain interference criteria for that Recommendations ITU-R SA.1160 and ITU-R SA.1163 contain interference criteria for Earth-to-space
3、cl Earth exploration-satellite and meteorological-satellite services, that it is necessary to have interference criteria for all command and data transmission systems operating in the recommends 1 that, for space-to-Earth data transmission links in bands other than those treated in Recommendations I
4、TU-R SA.1026, ITU-R SA.1160 and ITU-R SA.1163, the interference criteria for Earth receiving sites be established as follows: - for frequencies between 1 and 10 GHz, the power spectral density of noise-like interference or the total power of CW-type interference in any single band or in all sets of
5、bands shall not exceed -154 dEi(W/MHz) at the receiver input for more than 1% of the time; for frequencies less than 1 GHz, the permissible interference may increase at the rate of 20 dB per decreasing frequency decade; - 2 that, for Earth-to-space command and data transmission links in bands other
6、than those treated in Recommen- dations ITU-R SA.1160 and ITU-R SA.1163, the interference criteria for near-Earth spacecraft receivers be established as follows: - for frequencies between 300MHz and 10 GHz, the power spectral density of noise-like interference or the total power of CW-type interference in any single band or in all sets of bands 1 kHz wide shall not exceed -161 dEi(W/kHz) at the receiver input for more than 0.1% of the time; for frequencies less than 300 MHz, the permissible interference may increase at the rate of 20 dB per decreasing frequency decade. -
