Patent ID: 7603096

Claim:
A mixer with self-calibrating carrier leakage, comprising: a double balanced mixer; a gm stage comprising a first processing unit and a second processing unit; a current duplicating circuit to select the first processing unit or the second processing unit and duplicate a duplicated current of the selected processing unit; and a current measurement circuit for respectively receiving the duplicated current to generate a compensation current based on a current difference between the currents of the first processing unit and the second processing unit, wherein the current measurement circuit comprises: a capacitor having a first terminal and a second terminal, wherein the second terminal is grounded and the first terminal receives the duplicated current; a controller determining a charge time of the capacitor to generate a compensation signal, wherein the charge time is the time that the voltage of the capacitor is charged to equal to a reference voltage; and a current compensation unit receiving the compensation signal to generate a compensation current to the mixer.