METHOD AND APPARATUS FOR DEMODULATING COHERENT AND NON-COHERENT MODULATED SIGNALS

摘要

A receiver (FIG. 3) receives FSK and coherent 8PSK protocols. A selectively configurable processor (20) demodulates the message signals, and includes a demodulator (50-58) that derives in-phase and quadrature signals based on the message signals. A phase detector (60-64) is responsive to the in-phase and quadrature signals and delayed in-phase and quadrature signals to derive a phase signal. A selector (26) is responsive to the in-phase and quadrature signals to selectively connect a loop filter (66) between the phase detector and the demodulator. When the selector (26) connects the filter (66) between the phase detector (60-64) and demodulator (50-58), the demodulator is responsive to filtered phase signals to lock onto a frequency of the message signals so that the processor (20) operates as a phase locked loop to demodulate coherent modulated signals. When the selector (26) disconnects the filter (66) from between the phase detector (60-64) and the demodulator (50-58), the demodulator demodulates non-coherent modulated signals and the phase detector supplies a phase signal representing the slope of the phase of the demodulated signal.