EFFECTS OF INTERSYSTEM RADIO INTERFERENCE FROM WIDEBAND FM SIGNALS ON PSK SIGNAL.

Some practically optimal conditions for coexistence of analog and digital systems in an intersystem interference environment may be found in a compromise between both systems. To find them, as a first step, the authors have investigated and discussed the effects of multiple wideband FM systems upon an M-ary coherent PSK (MCPSK) system under the assumption that both systems are sharing the same radio frequency bands. The paper proposes an analysis method which is directly applicable to the wideband FM interferers. The symbol error performance of the MCPSK system in the presence of Gaussian noise and cochannel or adjacent channel interference from wideband FM systems is evaluated and given in graphs as functions of carrier-to-noise ratio, carrier-to-interferer ratio and normalized carrier separation. From the results obtained, one can expect some optimal or suitable operating conditions (frequency allocation, bandwidth and power) for a PSK channel in the intersystem interference from analog FM channels.