Introduction to Digital Signal and System Analysis - Tutorsindia
Introduction to Digital Signal and System Analysis - Tutorsindia
Introduction to Digital Signal and System Analysis - Tutorsindia
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<strong>Introduction</strong> <strong>to</strong> <strong>Digital</strong> <strong>Signal</strong> <strong>and</strong> <strong>System</strong> <strong>Analysis</strong><br />
Spectral <strong>Analysis</strong> by DFT<br />
%Examine signal components<br />
%sampling rate 1024Hz<br />
N=1024;<br />
dt=1/N;<br />
t=0:dt:1-dt;<br />
%****define the signal**<br />
x=0.1*sin(2*pi*32 .*t ) + ...<br />
0.2*sin(2*pi*107.5 .*t )+ ...<br />
0.15*sin(2*pi* 422.5 .*t ) ;<br />
%***********************<br />
subplot(2,1,1);<br />
plot(t,x);<br />
axis([0 1 -1 1]);<br />
xlabel(‚seconds‘);<br />
ylabel(‚x[n]‘);<br />
X=fft(x);<br />
df=1;<br />
f=0:df:N-1;<br />
subplot(2,1,2);<br />
plot(f,abs(X));<br />
axis([0 N/2 0 120]);<br />
xlabel(‚Hz‘);<br />
ylabel(‚|X[k]|‘);<br />
Q7.2 Use MATLAB code <strong>to</strong> apply rectangular, triangular <strong>and</strong> Hamming windows <strong>to</strong> the signal<br />
⎛ 2p<br />
72 n ⎞ ⎛ 2p196.5n<br />
⎞<br />
x[<br />
n]<br />
= 0.1sin⎜<br />
⎟ + 0.2sin⎜<br />
⎟ + 0.15<br />
⎝ 1024 ⎠ ⎝ 1024 ⎠<br />
⎛ 2p<br />
408n<br />
⎞<br />
sin⎜<br />
⎟<br />
⎝ 1024 ⎠<br />
Observe the level of magnitude <strong>and</strong> the distribution of side-lobs carefully <strong>to</strong> find any improvement of leakage reduction.<br />
Sketch the screen display <strong>and</strong> make your comments. Make sure the shape of the envelope in the time domain is drawn<br />
according <strong>to</strong> the window function.<br />
109<br />
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