Parallel PSK demodulator development

With increasing demands being placed on available bandwidth for data communications systems, there is a requirement for bandwidth efficient modulation protocols to minimize overall spectrum requirements. Often, it is also desirable to maintain low overall bit error rates, particularly in wireless applications such as HF radio.; Multiple carrier modulation techniques can provide high bandwidth efficiencies in both wireless and "land line" (wired) communications links. This thesis presents the development of a parallel phase shift keying demodulator, able to demodulate four simultaneous BPSK modulated independent carrier tones at keying speeds of 31.25 Baud. The system has also been proven to be able to isolate and demodulate single modulated channel carriers from 600 Baud BPSK up to 300 Baud 8PSK in a multiple parallel carrier environment. The previous generation PSK demodulator at UNB operated on a single DSP CPU, with a "conventional" single carrier tone signal. The work presented here is a parallel processing implementation on a multiprocessor platform, incorporating narrowband input signal filtering, demodulating up to four independent carrier tones simultaneously. Taking advantage of the powerful parallel processing functions of the DSP hardware, the demodulator remains flexible through software parameter reconfiguration to permit variations in carrier frequencies, modulation orders, and keying speeds on each carrier tone.