A bit error probability analysis of a digital PLL based demodulator of differentially encoded BPSK and QPSK modulation

Presents a bit error probability analysis of a digital phase-locked loop based demodulator, of differentially encoded BPSK and QPSK modulations. Differential decoding is a method of resolving a phase ambiguity, typical of fully modulated signals, that uses two consecutive demodulated symbols to estimate the information symbols. The effects of a noisy phase reference on demodulator performance are well documented for uncoded modulations (single symbol demodulation). The paper investigates performance for phase reference time variations between the two symbols. The time varying reference investigated is produced by a digital phase-locked loop. The noisy phase reference has negligible additional effect on the bit error probability for differentially encoded BPSK and QPSK