US Patent 7801505 Multipulse/multitone mixing receiver

An apparatus adapted for measuring the properties of periodic signals and a method for making such measurements is disclosed. The apparatus includes a LO signal generator, a mixer, a low pass filter and an output device. The LO signal generator generates an LO signal comprising a fundamental frequency ωLO and one or more higher harmonics with arbitrary amplitudes and phases. The mixer receives a periodic input signal having harmonics including a highest harmonic of interest, N, and a fundamental frequency, ωin. The mixer outputs an IF signal that is filtered. The filtered IF signal includes a frequency-compressed signal having M harmonics including a fundamental characterized by a frequency ωc<ωin. Each of the harmonics in the frequency-compressed signal corresponds to one of the harmonics in the input signal and has an amplitude related to the amplitude of the corresponding harmonic in the input signal.