Matlab Implementation of the Biquad

The two control parameters for this filter are

  1. the center frequency $ f_c$
  2. the quality factor $ Q$ (or bandwidth).

T = 1/44100;
Q = 20;
fc = 400;
Bw = fc/Q;

R = exp(-pi*Bw*T);

B = [1 0 -R];
A = [1 -2*R*cos(2*pi*fc*T) R*R];

[h, w] = freqz(B,A);

Use freqz, tf2zp and zplane to see how the spectrum corresponds to the plot of the poles and zeros in the z-plane.

Parameters can be changed in real-time, making this an efficient and ideal implementation for performance situations.


``Mus 270a: Introduction to Digital Filters'' by Tamara Smyth, Department of Music, University of California, San Diego.
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Copyright © 2019-02-25 by Tamara Smyth.
Please email errata, comments, and suggestions to Tamara Smyth<trsmyth@ucsd.edu>