### Navigation

- index
- modules |
- next |
- previous |
- SciPy v0.7 Reference Guide (DRAFT) »
- Signal processing (`scipy.signal`) »

# scipy.signal.iirdesign

`scipy.signal.``iirdesign`(wp, ws, gpass, gstop, analog=0, ftype='ellip', output='ba')

  Complete IIR digital and analog filter design.

  Given passband and stopband frequencies and gains construct an analog or digital IIR filter of minimum order for a given basic type. Return the output in numerator, denominator (‘ba’) or pole-zero (‘zpk’) form.

  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). ftype – The type of iir filter to design: : elliptic : ‘ellip’ Butterworth : ‘butter’, Chebyshev I : ‘cheby1’, Chebyshev II: ‘cheby2’, Bessel : ‘bessel’ output – Type of output: numerator/denominator (‘ba’) or pole-zero (‘zpk’) :
  Returns: | b,a – Numerator and denominator of the iir filter. : z,p,k – Zeros, poles, and gain of the iir filter.

### Navigation

- index
- modules |
- next |
- previous |
- SciPy v0.7 Reference Guide (DRAFT) »
- Signal processing (`scipy.signal`) »