Differential Detection of Duobinary CPFSK

Differential detection of duobinary CPFSK is analyzed to determine its performance as an alternative to other incoherent bandwidth efficient detection schemes. It is shown that a BPSK differential receiver can correctly detect a duobinary MSK signal when precoding (differential encoding) is employed at the transmitter. The effects of intersymbol interference due to IF filtering at the receiver are analyzed for a Gaussian and a 4th-order Butterworth IF filter. Furthermore, nonredundant error correction is shown to be feasible for differential detection of duobinary MSK and a method of analyzing the performance of the error correction receiver is presented.