www.gusucode.com > signal 案例源码程序 matlab代码 > signal/GenerateIIRFilterWithDirectFormIStructureExample.m

    %% Generate IIR Filter with Direct Form I Structure
% Design a 30th-order IIR Butterworth filter. Specify a cutoff frequency of
% _π_/4 rad/sample. Create a Simulink(R) block with a direct form I
% structure.

[b,a] = butter(30,0.25);
filt2block(b,a,'FilterStructure','directForm1')