Untitled4 - figure(2) stem(freqs, abs(fftshift(xz)));...

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%ECE spectrum analysis example %% create a signal with 2 frequencies omega_1=0.6*pi; omega_2=0.7*pi; n=0:1023; s = 0.7*cos(omega_1*n) + 0.3*cos(omega_2*n); stem(s); %% take a (rectangular)window of the signal N=32; x=s(1:32); stem(x), label('A rectangular window of signal'); s %% first approach: take the DFT(FFT) of x X=fft(x); N=32; freqs=pi*(-1:2/N:1-2/N); figure(1) stem(freqs, abs(fftshift(x))); label('FFT of x') %% Zero pad signal M=256; xz=zeros(1,M); xz(1:N)=x; Y=fft(y); freqs=[-1:2/M:(1-2/M)];
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Unformatted text preview: figure(2) stem(freqs, abs(fftshift(xz))); title('FFT of (x with zero pading)') %% we have Used the rectangular of window w_rect=ones(1,N); stem(w_rect) freqz(w_rect) title('Frequency respones of rect window') %% Now, letss use a better window w_ham = hamming(N) y=x.* w_ham'; subplot(2,1,1), stem(x), subplot(2,1,1), stem(y), %% Zero pad windowed signal M=256; yz= zeros(1,M); yz(1:N)=y; freqs = [-1:2/M:(1-2/M); subplot...
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This note was uploaded on 01/22/2011 for the course ECE 410 taught by Professor Staff during the Spring '08 term at University of Illinois, Urbana Champaign.

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