Demodulator for a radio receiver and method of operation

摘要

A demodulator (20) extracts a digital sub-carrier signal from a modulated signal and provides the sub-carrier signal in clock and data format. Demodulation occurs with two mixing stages (32, 40, 42) and at sampling frequencies that are independent from the frequency of transmission of the modulated signal. Matched filters (44, 46) try to match the received sub-carrier signal with a predefined bi-phase pulse shape. Phase correction is applied at a low sampling frequency. After phase correction, digital interpolation is used to re-sample the sub-carrier signal.