DOWN CONVERSION CIRCUIT

摘要

A down conversion circuit (30) for a receiver circuit (10) is disclosed the down conversion circuit 30 comprises a first passive switching mixer (70) arranged to down convert a received radio frequency RF signal with a first local oscillator LO signal (LO1) having a first duty cycle for generating a first down converted signal at an output port (75) of the first passive switching mixer (70). The down conversion circuit (30) further comprises a second passive switching mixer (80) arranged to down convert the received RF signal with a second LO signal (LO2) having the same LO frequency as the first LO signal (LO1) and a second duty cycle different from the first duty cycle for generating a second down converted signal at an output port (85) of the second passive switching mixer (80). In addition the down conversion circuit (30) comprises a passive output combiner network (90) operatively connected to the output ports (75 85) of the first passive switching mixer (70) and the second passive switching mixer (80) 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 (30). The passive output combiner network (90) is tunable to adjust magnitudes and phases of the first and the second down converted signals. A related quadrature down conversion circuit (50) a related receiver circuit (10) a related communication device (1 2) and a related calibration method are also disclosed.