RECURSIVE DIGITAL FILTERING WITH ZERO PHASE SHIFT

摘要

A method is described which allows numerical smoothing of data to be carried out recursively without inducing any phase shift. The phase shift is removed by averag¬ing the outputs from recursive digital filters operating in opposite directions over the data. A computer program, which embodies a functional minimisation algorithm, has been constructed for the filter synthesis. The synthesized filter is in the form of several low order filters to be implemented in tandem. This enables easy characterization of stability and tends to reduce the effects of computer round-off during filtering.