DESIGN OF DIGITAL ELLIPTIC BANDPASS FILTER

The design of a digital filter is presented. This filter is envisaged as replacing analogue bandpass filters for the band 312kHz to 552kHz which corresponds to supergroup 2 of the International Telegraph and Telephone Consultative Committee (CCITT) frequency plan. The design starts by considering the transformation of an elliptic low-pass analogue filter into a bandpass analogue filter which is then converted by bilinear transformation into the digital filter equivalent. The digital filter was simulated on a microcomputer and the results compare favourably with the results of Gray and Markel (1976) who have done similar work in the 3kHz to 4kHz band. © 1990 Taylor & Francis Ltd.