[SciPy-user] Analog band stop filter design

Kumar Appaiah akumar at iitm.ac.in
Thu Jan 25 07:06:00 CST 2007

Dear Scipy users,

I am unsure of how to use the filter design package to design analog
band stop filters.

For example, referring to the documentation, I came up with this code:

from scipy import *

omega_c1 = 430
omega_r1 = 350
omega_c2 = 600
omega_r2 = 700

gpass = 0.5
gstop = 40
(n, Wn) = signal.cheb1ord([omega_r1, omega_r2], [omega_c1, omega_c2], gpass, gstop, analog=1)
print n
print Wn

But the output is:
[429 699]

Now, I am sure I am doing something wrong, but I guess there is some
error checking which needs to be done in filter_design.py as well,
though I couldn't quite figure it out from the file. What is the


Kumar Appaiah,
462, Jamuna Hostel,
Indian Institute of Technology Madras,
Chennai - 600 036

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