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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 />

Time-domain <strong>Analysis</strong><br />

h[n]=1.5 h[n-1] -0.85 h[n-2] + δ[n]<br />

Let n=0, 1, 2, 3,…<br />

h[0]=0-0+1=1<br />

h[1]=1.5 ´1-0 -0=1.5<br />

h[2]=1.5´1.5-0.85´1+0=1.4<br />

h[3]=1.5´1.4-0.85´1.5+0 =0.825<br />

...<br />

Therefore, the impulse response h[n]=[1, 1.5, 1.4, 0.825, …].<br />

↑<br />

Generally for the difference equation:<br />

y[ n]<br />

= a1 y[<br />

n −1]<br />

+ a2<br />

y[<br />

n − 2] + a3<br />

y[<br />

n − 3] + ... + b1<br />

x[<br />

n −1]<br />

+ b2<br />

x[<br />

n − 2] + b3<br />

x[<br />

n − 3] + ...<br />

The impulse response can evaluated by the special equation with the simple unit impulse input:<br />

h[ n]<br />

= a1 h[<br />

n −1]<br />

+ a2h[<br />

n − 2] + ... + b1d [ n −1]<br />

+ b2d[<br />

n − 2] + ...<br />

(3.10)<br />

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