ex081000.m

matlab写的数字信号处理源代码,里面包括最基本的fft计算

% Chapter 8: Example 8.10
%            Impulse Invariance Transformation
%                  Simple example
%
subplot(1,1,1);
c = [1,1]; d = [1,5,6]; T = 0.1; Fs = 1/T;
[b,a] = imp_invr(c,d,T)
%%b =  1.0000   -0.8966
%%a =  1.0000   -1.5595    0.6065
% Impulse response of the analog filter
t = [0:0.01:3]; [ha,ta] = impulse(c,d,t);
subplot(2,1,1); plot(t,ha); axis([0,3,-0.1,1]);hold on
% Impulse response of the digital filter
n = [0:1:3/T]; hn = filter(b,a,impseq(0,0,3/T));
stem(n*T,hn); xlabel('time in sec'); title ('Impulse Responses');
hold off
% Magnitude Response of the digital filter
[db,magd,pha,grd,wd] = freqz_m(b,a);
% magnitude response of the analog filter
[db,mags,pha,ws] = freqs_m(c,d,2*pi*Fs);
subplot(2,1,2); plot(ws/(2*pi),mags*Fs,wd/(2*pi)*Fs,magd)
xlabel('frequency in Hz'); title('Magnitude Responses');
ylabel('Magnitude'); 
text(1.4,.5,'Analog filter'); text(1.5,1.5,'Digital filter')