scipy tutorial - Baustatik-Info-Server

H(s) = —— = ———————————————-
a(s) a[0] x**(N-1) + a[1] x**(N-2) + ... + a[N-1]
r[0] r[1] r[-1]
= ——– + ——– + ... + ——— + k(s)
(s-p[0]) (s-p[1]) (s-p[-1])
SciPy Reference Guide, Release 0.8.dev
If there are any repeated roots (closer than tol), then the partial fraction expansion has terms like
See Also:
r[i] r[i+1] r[i+n-1]
——– + ———– + ... + ———– (s-p[i]) (s-p[i])**2 (s-p[i])**n
residue, poly, polyval, unique_roots
3.13.5 Matlab-style IIR filter design
butter(N, Wn[, btype, analog, output]) Butterworth digital and analog filter design.
buttord(wp, ws, gpass, gstop[, analog]) Butterworth filter order selection.
cheby1(N, rp, Wn[, btype, analog, output]) Chebyshev type I digital and analog filter design.
cheb1ord(wp, ws, gpass, gstop[, analog]) Chebyshev type I filter order selection.
cheby2(N, rs, Wn[, btype, analog, output]) Chebyshev type I digital and analog filter design.
cheb2ord(wp, ws, gpass, gstop[, analog]) Chebyshev type II filter order selection.
ellip(N, rp, rs, Wn[, btype, analog, output]) Elliptic (Cauer) digital and analog filter design.
ellipord(wp, ws, gpass, gstop[, analog]) Elliptic (Cauer) filter order selection.
bessel(N, Wn[, btype, analog, output]) Bessel digital and analog filter design.
butter(N, Wn, btype=’low’, analog=0, output=’ba’)
Butterworth digital and analog filter design.
Description:
Design an Nth order lowpass digital or analog Butterworth filter and return the filter coefficients in
(B,A) or (Z,P,K) form.
See also buttord.
buttord(wp, ws, gpass, gstop, analog=0)
Butterworth filter order selection.
Return the order of the lowest order digital Butterworth filter that loses no more than gpass dB in the passband
and has at least gstop dB attenuation in the stopband.
Parameters
wp, ws – Passband and stopband edge frequencies, normalized from 0 :
to 1 (1 corresponds to pi radians / sample). For example:
Lowpass: wp = 0.2, ws = 0.3 Highpass: wp = 0.3, ws = 0.2 Bandpass: wp =
[0.2, 0.5], ws = [0.1, 0.6] Bandstop: wp = [0.1, 0.6], ws = [0.2, 0.5]
gpass – The maximum loss in the passband (dB). :
gstop – The minimum attenuation in the stopband (dB). :
analog – Non-zero to design an analog filter (in this case wp and :
ws are in radians / second).
3.13. Signal processing (scipy.signal) 339