Sampling in-phase and quadrature components of band-pass signals

摘要

A filtering method for sampling the lowpass equivalent of a bandpass analog signal is introduced. This input is sampled at exactly twice the sampling rate of the in-phase and quadrature components provided at the output. The sampling frequency determination and the lowpass decimator filter design are straightforward. The practical implementation of the sampling method is accomplished by the polyphase realization of the filter; this implementation is particularly suitable for linear phase FIR designs.