ZPLANE Z-plane zero-pole plot.
ZPLANE(Z,P) plots the zeros Z and poles P (in column vectors) with the
unit circle for reference. Each zero is represented with a 'o' and
each pole with a 'x' on the plot. Multiple zeros and poles are
indicated by the multiplicity number shown to the upper right of the
zero or pole. ZPLANE(Z,P) where Z and/or P is a matrix, plots the zeros
or poles in different columns using the colors specified by the axes
ColorOrder property.
ZPLANE(B,A) where B and A are row vectors containing transfer function
polynomial coefficients plots the poles and zeros of B(z)/A(z). Note
that if B and A are both scalars they will be interpreted as Z and P.
[HZ,HP,Hl] = ZPLANE(Z,P) returns vectors of handles to the lines and
text objects generated. HZ is a vector of handles to the zeros lines,
HP is a vector of handles to the poles lines, and Hl is a vector of
handles to the axes / unit circle line and to text objects which are
present when there are multiple zeros or poles. In case there are no
zeros or no poles, HZ or HP is set to the empty matrix [].
ZPLANE(Z,P,AX) puts the plot into the axes specified by the handle AX.
[HZ,HP,Hl] = ZPLANE(D) plots the poles and zeros of digital filter D.
You design a digital filter, D, by calling the
designfilt function.
% Example 1:
% Design a lowpass FIR filter with normalized cut-off frequency at
% 0.3 and show its zero-pole plot.
b=fircls1(54,0.3,0.02,0.008);
zplane(b) % zero-pole plot for filter
% Example 2:
% Design a 5th order lowpass elliptic IIR filter and show its
% zero-pole plot.
[b,a] = ellip(5,0.5,20,0.4);
zplane(b,a) % zero-pole plot for filter
% Example 3:
% Design a lowpass Butterworth IIR filter and show its Zero-Pole
% plot.
[z,p] = butter(4,0.15);
zplane(z,p) % zero-pole plot for filter
% Example 4:
% Use the designfilt function to design a highpass IIR digital filter
% with order 8, passband frequency of 75 KHz, and a passband ripple
% of 0.2 dB. Sample rate is 200 KHz. Visualize the zero-pole plot.
D = designfilt('highpassiir', 'FilterOrder', 8, ...
'PassbandFrequency', 75e3, 'PassbandRipple', 0.2,...
'SampleRate', 200e3);
zplane(D)
See also FREQZ, GRPDELAY, IMPZ, FVTOOL.
Documentation for zplane
doc zplane
