www.gusucode.com > signal 案例源码程序 matlab代码 > signal/MagnitudeResponseOfAHighpassFilterExample.m
%% Magnitude Response of a Highpass Filter % Design a 3rd-order highpass Butterworth filter having a normalized 3-dB frequency % of $0.5\pi$ rad/sample. Compute its frequency response. Express the magnitude % response in decibels and plot it. % Copyright 2015 The MathWorks, Inc. [b,a] = butter(3,0.5,'high'); [h,w] = freqz(b,a); dB = mag2db(abs(h)); plot(w/pi,dB) xlabel('\omega / \pi') ylabel('Magnitude (dB)') ylim([-82 5]) %% % Repeat the computation using |fvtool|. fvtool(b,a)