Continuous Phase Chirp (CPC) Signals for Binary Data Communication-Part I: Coherent Detection

Chirp (linear FM) signals provide an attractive wideband digital modulation scheme in applications where interference rejection is important. This paper evaluates the error rate (performance) of coherent binary continuous phase chirp (CPC) receivers operating on the additive white Gaussian noise (AWGN) channel and determines the improvement in performance made possible by multiple bit observation. In particular, it is shown that a receiver with two bit observation, giving up to 1.75 dB signal-to-noise ratio (SNR) improvement over the optimum single bit chirp receiver, provides a good compromise between SNR gain and system complexity. Furthermore, a simple, suboptimum, average matched filter (AMF) receiver is analyzed, and it is shown that a two-bit observation is optimum, giving a performance equivalent to that of antipodal phaseshift keying (PSK). An implementation of this receiver in the form of in-phase and quadrature demodulators is also derived.