Patent ID: 7406137

Claim:
A carrier recovery system comprising: an in-phase mixer for mixing an incoming signal with an in-phase reference signal to produce an in-phase baseband signal; a quadrature-phase mixer for mixing the incoming signal with a quadrature-phase reference signal to produce a quadrature-phase baseband signal; a DC detector for measuring a DC offset of the quadrature-phase baseband signal; and a frequency synthesizer for generating the in-phase reference signal and the quadrature-phase reference signal according to the DC offset measured by the DC detector; wherein the DC detector comprises: an adder for adding the quadrature-phase baseband signal to a feedback signal for producing an added value; delay unit coupled to the adder for generating an output being the added value delayed by a predetermined time; and multiplier coupled to the delay unit is used for multiplying the output of the delay unit by a predetermined coefficient to produce the feedback signal.