Infinite impulse response filter 2nd,3rd order high pass Bilinear approximation.

Cuthbert Nyack
The sampled "equivalent" of a second and third order Butterworth high pass filter derived by use of the bilinear approximation is shown in the applets below. The Butterworth filter has an lower 3dB frequency of 1rad/s. First applet shows a second order filter and the second shows a third order filter. In applet below vertical scale is from 0 to 4/3 for amplitude, -pi to pi/3 for phase and horizontal scale is from 0 to 4rad/s.

In both applets red shows the sampled filter response, orange shows the analog filter response, green shows the sampled filter phase and cyan shows the analog filter phase.

Return to main page
Return to page index
COPYRIGHT © 1999 Cuthbert A. Nyack.