On Differential Detection of Binary FM

Differential detection of binary frequency-shift keyed signals (binary FM) is analyzed. It is shown that, by proper selection of the delay interval, the error rate of differentially detected binary FM can be made equal to the error rate of binary DPSK provided that the modulation index
h
satisfies
h \geq 0.5
. If
h > 0.5
, it is shown that the differential detection of binary FM yields poorer performance than DPSK.