Patent ID: 7860192
Filing Date: 2010-12-28
Classification: H04L

Abstract:
1. A frequency shift keying (FSK) demodulator with build-in band-pass filter, the FSK demodulator comprising: a band-pass filter, which is used as a phase shifter of the FSK demodulator for shifting phase of an FSK signal to generate a revised FSK signal; an auto-calibration loop coupled to the band-pass filter for adjusting a center frequency of the band-pass filter, wherein the auto-calibration loop comprises: a phase comparator including a first input end coupled to an output end of the band-pass filter, and a second input end for receiving the FSK signal, the phase comparator used for comparing the FSK signal with the revised FSK signal for a phase difference and outputting a comparison result; and an analog-to-digital converter coupled to the phase comparator for converting the comparison result into digital data.