| 摘要 |
Within a differential detection demodulator, a received signal is first quantized by a limiter amplifier and then subjected to frequency conversion by a frequency converter. The frequency converter circuit converts a frequency of a first 2-level signal using a second 2-level signal having a frequency distinct from the frequency of that first signal, and includes: an exclusive OR element for obtaining a logical exclusive OR element of the first and second signal; running average generator means, coupled to the exclusive OR element, for generating a signal corresponding to k times a running average of an output of the exclusive OR element, k being a positive integer; and hard decision means, coupled to the running average generator means, for converting an output of that running average generator means to a 2-level logical signal. In response to the output of the frequency converter, a phase comparator outputs a relative phase signal representing the phase shift of the received signal after frequency conversion relative to the phase reference signal.
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