[Numpy-discussion] Q: Use of scipy.signal.bilinear

[R Schumacher]

We have a function which describes a frequency response correction to
piezo devices we use. To flatten the FFT, it is similar to:
Cdis_t = .5
N = 8192
for n in range(8192):
B3 = n * 2560 / N
Fc(n) = 1 / ((B3/((1/(Cdis_t*2*pi))**2+B3**2)**0.5)*(-0.01*log(B3)
+ 1.04145))

In practice it really only matters for low frequencies.

I suggested that we might be able to do a time domain correction as a
forward-reverse FFT filter using the function, but another said it
can also be applied in the time domain using a bilinear transform.
So, can one use
http://docs.scipy.org/doc/scipy-0.16.0/reference/generated/scipy.signal.bilinear.html
and, how does one generate b,a from the given Fourrier domain
flattening function?

I'd guess someone here has done this...

- Ray

[Charles R Harris]

Post by R Schumacher
We have a function which describes a frequency response correction to
Cdis_t = .5
N = 8192
B3 = n * 2560 / N
Fc(n) = 1 / ((B3/((1/(Cdis_t*2*pi))**2+B3**2)**0.5)*(-0.01*log(B3) +
1.04145))
In practice it really only matters for low frequencies.
I suggested that we might be able to do a time domain correction as a
forward-reverse FFT filter using the function, but another said it can also
be applied in the time domain using a bilinear transform.
So, can one use
http://docs.scipy.org/doc/scipy-0.16.0/reference/generated/scipy.signal.bilinear.html
and, how does one generate b,a from the given Fourrier domain flattening
function?

This should go to either scipy-***@scipy.org or scipy-***@scipy.org

Chuck

[R Schumacher]

Sorry - I'll join there.

- Ray

On Tue, Dec 8, 2015 at 9:30 AM, R Schumacher
We have a function which describes a frequency
response correction to piezo devices we use. To
Cdis_t = .5
N = 8192
 B3 = n * 2560 / N
 Fc(n) = 1 /
((B3/((1/(Cdis_t*2*pi))**2+B3**2)**0.5)*(-0.01*log(B3) + 1.04145))
In practice it really only matters for low frequencies.
I suggested that we might be able to do a time
domain correction as a forward-reverse FFT
filter using the function, but another said it
can also be applied in the time domain using a bilinear transform.
So, can one use
<http://docs.scipy.org/doc/scipy-0.16.0/reference/generated/scipy.signal.bilinear.html>http://docs.scipy.org/doc/scipy-0.16.0/reference/generated/scipy.signal.bilinear.html
and, how does one generate b,a from the given
Fourrier domain flattening function?
This should go to either
Chuck
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