A signal modulated by frequency-shift keying is input to a detector consisting of an instantaneous phase detection circuit that detects the instantaneous phase of the input signal, a differentiating circuit that differentiates the instantaneous phase to obtain the instantaneous frequency, and a baseband...http://www.google.fr/patents/US5539355?utm_source=gb-gplus-shareBrevet US5539355 - Frequency-shift-keying detector using digital circuits
Frequency-shift-keying detector using digital circuits
