Demodulator for use in wireless communications and receiver, method and terminal using it

摘要

A demodulator (100) for demodulating a frequency modulated RF signal (x(t)), includes an input signal path (101) for delivering an RF input signal, a local oscillator (111), connected to the input signal path a first mixer (107) for mixing an output reference signal from the local oscillator with an RF input signal to produce an in-phase component of the input received signal, a phase shifter (113), connected to the input signal path a second mixer (109) for mixing an output reference signal from the local oscillator via the phase shifter with the RF input signal to produce a quadrature component of the RF input signal; and an output signal processor (119) for producing an output demodulated information signal by producing a function of the in-phase and quadrature components; and wherein the demodulator is periodically operable in a quadrature phase error determination mode wherein the reference signals produced by the local oscillator have a frequency which is offset from the carrier frequency of an RF input signal. Also described is a RF receiver, method and terminal using the demodulator.