www.gusucode.com > signal 案例源码程序 matlab代码 > signal/PolesAndZerosOfAnEllipticLowpassFilterExample.m
%% Poles and Zeros of an Elliptic Lowpass Filter % For data sampled at 1000 Hz, plot the poles and zeros of a 4th-order % elliptic lowpass digital filter with cutoff frequency 200 Hz, 3 dB of % ripple in the passband, and 30 dB of attenuation in the stopband. % Copyright 2015 The MathWorks, Inc. %% [z,p,k] = ellip(4,3,30,200/500); zplane(z,p) grid title('4th-Order Elliptic Lowpass Digital Filter') %% % Create the same filter using |designfilt|. Use |fvtool| to plot its poles % and zeros. d = designfilt('lowpassiir','FilterOrder',4,'PassbandFrequency',200, ... 'PassbandRipple',3,'StopbandAttenuation',30, ... 'DesignMethod','ellip','SampleRate',1000); zplane(d)