Almost-coherent detection of phase-shift-keyed signals using an injection-locked oscillator

We analyze a proposed scheme of detection of phase-shift-keyed signals using an injection-locked oscillator the bandwidth of which is much less than the modulation rate. The output of the oscillator is a carrier with essentially all of its modulation removed. We analyze the effect of noise and signal modulation on the phase of this reference tone and compute its effect on the probability of detection error. If a suitable encoder and decoder are used for the transmitted signal, this technique can provide nearly ideal coherent demodulation.