Patent ID: 8515380

Claim:
An apparatus comprising: a transconductance circuit that receives an input signal and that generates a first amplified signal and a second amplified signal; and a mixing circuit having: a first mixer that is coupled to the transconductance circuit so as to receive the first amplified signal, wherein the first mixer mixes the first amplified signal with a mixing signal, wherein the mixing signal has a duty cycle that is a fraction of a local oscillator duty cycle; a second mixer that is coupled to the transconductance circuit so as to receive the second amplified signal, wherein the second mixer mixes the second amplified signal with the mixing signal; an first impedance network that is coupled each of the first and second mixers, wherein the first impedance network is adapted to have an feedback impedance; a second impedance network that is coupled each of the first and second mixers, wherein the second impedance network is adapted to have the feedback impedance; and a differential amplifier that is coupled to each impedance network, wherein the mixing circuit further comprises: a first capacitor that is coupled between the transconductance circuit and the first mixer; and a second capacitor that is coupled between the transconductance circuit and the second mixer, wherein the first impedance network further comprises: a first resistor that is coupled to the first mixer; a second resistor that is coupled in series with the first resistor, wherein a collective impedance of the first and second resistors is approximately equal to the feedback impedance, and wherein the second mixer is coupled to a node between the first and second resistors; and a first switch that is coupled in parallel to the first resistor.