Optimum processing of multilevel CPFSK

The improved probability of error of a narrowband continuous phase M-ary frequency shift keying (CPMFSK) system of B b/s/Hz (B>2) with a limiter-discriminator-integrator detector when compensating for the effect of the bandlimiting filter using a nonlinear postprocessor following the FM discriminator is determined. This postprocessor uses an adaptive decision scheme to combat the severe intersymbol interference caused by the bandlimiting filter. Error probability results are presented for the receiver, both with and without a postprocessor, as a function of various system parameters for M=2, 4, 8, and 16 symbols to support the superiority of this algorithm.<
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