Patent ID: 7801505

Claim:
An apparatus comprising: an LO signal generator that generates an LO signal; a mixer having a first port that receives a periodic input signal having harmonics including a highest harmonic of interest, N, said harmonics comprising a fundamental frequency ω in and one or more higher frequency harmonics, each of said harmonics being characterized by an amplitude and phase, said mixer further comprising a local oscillator port that receives said LO signal and an output port that provides an IF signal; a low pass filter that filters said IF signal to generate a filtered IF signal; and an output device that outputs an output signal related to said filtered IF signal to a device external to said apparatus; wherein said filtered IF signal comprises a signal having frequency components including a frequency component having a frequency ω c and one or more higher harmonics, each frequency component corresponding to one of said harmonics in said input signal and having an amplitude related to said amplitude of said corresponding harmonic in said input signal, wherein ω c <ω in , and wherein said LO signal comprises a periodic signal comprising a fundamental frequency ω LO and one or more higher harmonics, wherein one of said harmonics in said LO signal has a phase that is different from another of said harmonics in said LO signal.