The error-rate performance of the high-speed QPSK digital satellite communication system with cochannel large capacity FDM-PM signal interference is studied by means of computer simulation. On the basis of the satellite signal’s narrowband transmission characters

base-band equivalent models of the satellite high-speed QPSK modem system

TWT no-nlinearity

large capacity FDM-FM interfering signal and noise are derived and realized in the computer. A computer simulation system is constructed

which is suitable for studying the error-rate performance of the high-speed QPSK digital satellite communication system under interference and noise. Using this equivalent system

the transmission error-rates of the high- speed QPSK satellite signal are simulated under varying signal-to-interference ratios and varying signal-to-noise ratios

the error-rate performance curves with up-link and down-link large-capacity FDM-FM signal interference are obtained

and the simulasion results are discussed.