Patent ID: 7643802

Claim:
A mixer circuit comprising: a first oscillator to provide a first signal having a first frequency; a second oscillator to provide a second signal having a second frequency; an up-conversion mixer having a first input terminal coupled to the first oscillator an output terminal to provide an output signal, the up-conversion mixer exhibiting a leakage from its first terminal to the output terminal; a down-conversion mixer having a first input terminal coupled to the output terminal of the up-conversion mixer, a second input terminal coupled to the second oscillator, and provides a down-conversion signal at an output terminal by downconverting the output signal of the up-conversion mixer; a detection and control unit coupled to the down-conversion mixer to detect a spurious signal in the down-converted signal, the spurious signal indicating the leakage of the up-conversion mixer, and to generate a leakage correction signal according to the spurious signal; and a multiplexer having a first input terminal coupled to the first oscillator and a second input terminal coupled to the second oscillator and an output terminal coupled to the down-conversion mixer.