Decimation circuit and method for filtering quantized signals while providing phase angle correction with a substantially linear phase response

摘要

A decimation circuit for filtering a stream of quantized electrical signals while providing phase angle correction and a substantially linear phase response over a predetermined passband range FB is provided. The stream of quantized electrical signals arrives at a predetermined rate FM from an oversampling delta-sigma modulator. The decimation circuit includes a decimation filter for filtering the stream of quantized electrical signals to provide a filtered output signal at an output ram F'S defined by F'S=FM/R wherein R is a positive integer. A phase corrector is coupled to the decimation filter to receive the filtered output signal and to correct the phase angle of the received filtered signal so as to provide an equalized phase angle at least over the predetermined range FB. The value for R is selected such that output rate F'S is sufficiently situated above bandpass range FB such that the phase corrector provides a desired substantially linear phase response over the passband range FB.