Comparison of correlator configurations for band-limited FSK demodulation

Comparisons of the performance of different types of correlator receivers and the limiter-discriminator for FSK (frequency shift keying) demodulation are presented, based on a modification of the analysis used by N. Ekanayake (1984), which allows the IF (intermediate frequency) bandlimiting to be taken into account. It is shown that for optimal values of IF bandwidth and deviation ratio, all receivers perform about the same, hence, the choice of receiver type can be made based on implementational considerations. To this end, the signal-to-interference ratio is introduced as a possible criterion for selecting the receiver type. Further, some of the correlator types considered possess the capability of being tuned, allowing them to perform better for larger values of the deviation ratio and IF bandwidth. It is shown that the conditions for optimal Pe performance of FSK are modified when sampling offset is considered