Differential phase-shift keying applied to chirp data signals

Chirp communication systems have been constructed that use signals having ascending and descending linear frequency sweeps to define mark and space data states, respectively. Such signal states are approximately orthogonal, and are generally detected noncoherently. The paper describes preliminary investigations into a method of differential phase modulation applied to chirp data signals. This improves the chirp-system performance in white noise and single carrier interference, and essentially retains the inherent protection that chirp signals have in multipath conditions. Also, improved bandwidth utilisation may be achieved with multiphase operation.