Design of Linear Phase IIR Filters with Application to Processing of Seismic Data

Abstract

It is possible to design FIR filters with exact linear phase, however high orders are required. Typical group delay specifications can be met with approximately linear‐phase IIR filters of lower order, resulting increased processing speed. In this paper, a lower order linear phase IIR filter is designed from a corresponding FIR one via model reduction techniques. Also, the effects of linear phase FIR and IIR filtration on acquired seismic signals are demonstrated. It is found that the filtration effects are similar, with IIR filter order of only one‐ half that of FIR, which recommends the changing of FIR filters chain in NRIAG (National Research Institute of Astronomy and Geophysics) digital seismic stations by their alternatives IIR.