Synthesis of a fractional order audio boost filter

Abstract

This paper introduces a fractional order audio band pass boost filter. The boost filter is part of the equalizer along with the cut filter: the first (e.g. the boost) is a band pass filter whereas the second is a stop band filter. These types of audio filters are widely used for their effectiveness in removing noise and echo. This paper will treat the boost filter only. The integer order filter will be first introduced. Then, the fractional order form — which has less number of parameters — along with its rationalization and its discrete form will be presented. The main advantages of using the fractional form will be also shown. A comparison between the initial audio file spectrum and the two synthesized filters (integer and fractional) will be presented and analyzed. Results showed that dealing with fractional orders will increase the selectivity and makes the filter more tunable but at the cost of gain which can be compromised using an amplifier.