A radio frequency (RF) demodulation circuit comprising a harmonic
rejection mixing stage capable of receiving and mixing an incoming radio
frequency (RF) signal having a frequency RF and a reference local
oscillator (LO) signal having a frequency LO and generating an output
signal in which out-of-band harmonic signals are suppressed. The harmonic
rejection mixing stage comprises 1) a multiphase local oscillator (LO)
generator for receiving the reference LO signal and generating M
phase-shifted local oscillator signals having frequencies LO and 2) M
mixers, each of the M mixers receiving the incoming radio frequency
signal and one of the M phase-shifted local oscillator signals. Each of
the M mixers generates a subcomponent signal. The subcomponent signals
are then scaled and combined to produce the output signal.