exa2_4.m

matlab应用实例。如：FIR、IIR数字滤波器设计等。

% exa2-4_dft.m, for example 2-4
% to test dft.m

N=32; %length of sequence
n=0:N-1; %time sample
xn=cos(pi*n/6); %generate sequence
k=0:N-1; %frequency sample
WN=exp(-j*2*pi/N);
nk=n'*k;
WNnk=WN.^nk;
Xk=xn*WNnk; %compute DFT
%plot sequence and its DFT
figure(1)
stem(n,xn)
figure(2)
stem(k,abs(Xk))