Direct demodulation method and apparatus

摘要

A demodulation circuit providing for detection of multiple zero-crossings in an FSK signal. High data rate signals are demodulated by generating, for each pair of baseband signals I and Q, additional I and Q pairs which are phase shifted from the original I and Q pair. By generating zero crossing signals for the original baseband signals and for the phase shifted signals, additional zero crossings may be detected allowing demodulation of relatively high data rate modulated signals.