Hello,
I was having a look at the scipy.signal.decimate() function and I
noticed some strange looking code:
elif ftype == 'iir':
if n is None:
n = 8
system = dlti(*cheby1(n, 0.05, 0.8 / q))
b, a = system.num, system.den
This is used to setup the anti aliasing low pass filter. What I don't
understand is the dance to obtain the IIR numerator and denominator
coefficients. Couldn't the above be simply as the code below?
elif ftype == 'iir':
if n is None:
n = 8
b, a = cheby1(n, 0.05, 0.8 / q)
Am I missing something?
Thanks!
Cheers,
Dan