Frequency Response, Transfer function and pole locations are shown by the applet below.

Fn = 0 shows the frequency response.

Fn = 1 shows the transfer function represented as a product of quadratic factors.

Fn = 2 shows the pole locations for the continuous Chebychev filter and the discrete Bilinear approximation.

To design a filter which has a gain of ~ -2dB at 0.1w

Set BL = 75, WL to 150 and R = 0.1 to locate the frequency markers and set the pass band ripple.

Adjust N, fc/fs until the conditions are met.

In this case N = 8 and fc/fs = 0.101.

The last entry in the first line of white text shows the gain at 0.2w

Changing Fn to 1 shows the quadratic factors needed to realize the filter and Fn = 2 show the poles.

COPYRIGHT © 2008 Cuthbert Nyack.