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41．Try to give a program to evaluate the following DTFT in the range  :

Then run the Program and compute the real and imaginary parts of the DTFT, and the magnitude and phase spectra. Is the DTFT a periodic function of w? If it is, what is the period?. Can you explain the jump in the phase spectrum? The jump can be removed using the MATLAB command "unwrap". Evaluate the phase spectrum with the jump removed.


num=[1.35 4.95 8.55 4.95 1.8];
den=[0.9 -1.8 1.65 -0.75 0.15];
W=0:0.01*pi:pi;
h=freqz(num,den,W);
hreal=real(h)
himag=imag(h)
subplot(2,1,1),stem(W,abs(h));
title('magnitude spectra');
subplot(2,1,2),stem(W,angle(h));
title('phase spectra');
figure(2),stem(W,unwrap(angle(h)));
title('unwraped phase');


[ 此帖被一凡在2008-01-12 11:25重新编辑 ]

Quote:

引用第7楼紫爱jean于2008-01-14 12:45发表的  :
明天要考了，还是什么都不会，着急啊.....

同着急