EFFECT OF A SOFT-LIMITER ON THE ERROR RATE OF AN M-ARY CPSK SYSTEM.
Abstract
The performance of an M-ary coherent phase shift keyed (CPSK) system over a channel which exhibits a soft-limiting input-output envelope characteristic is investigated. The nonlinearity is inserted between two channel noise sources. An expression for the error probability is obtained in terms of both noise powers and for various values of a limiter softness factor. It is shown that in a certain range of signal to noise ratios the presence of the soft-limiter provides some marginal improvement in the performance of binary CPSK systems, but that in all other situations it causes degradation in performance. The present analysis also yields results for a hard-limited channel as a limiting case.