Sensitivity simulation results for a direct-conversion FSK receiver

Results of computer simulation of a direct-conversion FSK (frequency-shift keyed) receiver are reported. The demodulation sensitivity depends strongly on the characteristics of the channel and postdetection filters. The sensitivity is defined as the Eb/No ratio at a bit-error rate of 10/sup -2/. The authors evaluated the dependence of the receiver sensitivity for bandwidth, section order, and filter type as parameters. Sensitivity degradation caused by the local frequency drift was determined. A phase detection technique for this type of receiver, which improves the sensitivity by 2 dB, is proposed.