High-Order Digital Parametric Equalizer Design

Sophocles J. Orfanidis
ECE Department, Rutgers University
94 Brett Road, Piscataway, NJ 08854-8058, USA

Email: orfanidi@ece.rutgers.edu
Tel: 732-445-5017
Date: June 15, 2005

This toolbox contains a collection of MATLAB functions for designing high-order digital parametric equalizer filters based on Butterworth, Chebyshev, and elliptic analog prototypes, and for their implementation in frequency-shifted transposed, normalized lattice, and optimum state-space forms. High-order equalizers provide flatter passbands and sharper bandedges at the expense of higher computational cost. The conventional biquadratic equalizer is obtained as a special case, and its optimum minimum roundoff-noise state-space form is included. The functions may also be used to design conventional lowpass, highpass, bandpass, and bandstop filters.

A subset of this toolbox includes functions for the computation of the Jacobian elliptic functions at complex arguments based on the Landen transformation, the computation of their inverses, elliptic integrals, solutions of the degree equation, and evaluation of the elliptic rational function.

Reference: Sophocles J. Orfanidis, "High-Order Digital Parametric Equalizer Design," J. Audio Eng. Soc., vol. 53, pp. 1026-1046, Nov. 2005.