www.gusucode.com > dsp 案例源码程序 matlab代码 > dsp/DesignAChebyshevTypeIIFilterExample.m
%% Design a Chebyshev Type II Filter % Construct a default lowpass filter specification object and design a % Chebyshev Type II filter. d = fdesign.lowpass; %% % Use |matchexactly| option to ensure the performance of the filter in the % passband. LowpassCheb2 = design(d,'cheby2','matchexactly','passband'); %% % Use |fvtool| to view the resulting filter fvtool(LowpassCheb2) %% % Construct a highpass filter specification object and design a % Chebyshev Type II filter. % Specify the filter order, stopband edge frequency, and the stopband % attenuation to get the filter exactly as required. d = fdesign.highpass('n,fst,ast',5,20,55,50); HighpassCheb2 = design(d,'cheby2'); %% % Use |fvtool| to view the resulting filter fvtool(HighpassCheb2) %% % By design, |cheby2| returns filters that use second-order sections (SOS). % For many applications, and for most fixed-point applications, SOS filters % are particularly well-suited.