Patent ID: 9356634
Filing Date: 2016-05-31
CPC Classification: H03D,H04B

Claim Text:
1. A down-conversion circuit for a receiver circuit, comprising: a first passive switching mixer arranged to down-convert a received radio frequency (RF) signal with a first local oscillator (LO) signal having a first duty cycle for generating a first down-converted signal at an output port of the first passive switching mixer; a second passive switching mixer arranged to down-convert the received RF signal with a second LO signal having the same LO frequency as the first LO signal and a second duty cycle, different from the first duty cycle, for generating a second down-converted signal at an output port of the second passive switching mixer; and a passive output combiner network operatively connected to the output ports of the first passive switching mixer and the second passive switching mixer and arranged to combine the first and the second down-converted signals such that harmonically down-converted signal content present in the first down-converted signal and harmonically down-converted signal content present in the second down-converted signal cancel in a combined output signal of the down-conversion circuit; wherein: the passive output combiner network is tunable to adjust magnitudes and phases of the first and the second down-converted signals; and the first and the second down-converted signals are differential signals and the output port of the first passive switching mixer and the output port of the second passive switching mixer are both differential output ports, each having a first and a second output terminal; and wherein the passive output combiner network comprises: a first resistor operatively connected between the first output terminal of the output port of the first passive switching mixer and a first summing node of the down-conversion circuit; a second resistor operatively connected between the first output terminal of the output port of the second passive switching mixer and the first summing node of the down-conversion circuit; a third resistor operatively connected between the second output terminal of the output port of the first passive switching mixer and a second summing node of the down-conversion circuit; and a fourth resistor operatively connected between the second output terminal of the output port of the second passive switching mixer and the second summing node of the down-conversion circuit.