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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 />

Z Domain <strong>Analysis</strong><br />

Definition or property <strong>Signal</strong> z-transform<br />

z-transform definition x[n]<br />

X ( z)<br />

= x[<br />

n]<br />

z<br />

Inverse z-transform<br />

x[<br />

n]<br />

1<br />

2π j<br />

<br />

X (z)<br />

n−1<br />

= X ( z)<br />

z dz<br />

Linearity ax n]<br />

+ bx [ ]<br />

aX z)<br />

+ bX ( )<br />

1[ 2<br />

n<br />

Time-shifting property x n n ] u[<br />

n − ]<br />

Convolution [ n]*<br />

y[<br />

n]<br />

−n0<br />

[ −<br />

0<br />

n0<br />

X ( z)<br />

z<br />

∞<br />

n=<br />

0<br />

1( 2<br />

z<br />

x X ( z) Y ( z)<br />

−n<br />

5.5 Z-plane, poles <strong>and</strong> zeros<br />

For the z-transform of a digital signal or a transfer function of an LTI system, generally it can be expressed as fac<strong>to</strong>rised<br />

form for both the numera<strong>to</strong>r <strong>and</strong> denomina<strong>to</strong>r:<br />

N ( z)<br />

K(<br />

z − z1)(<br />

z − z2<br />

)( z − z3)...<br />

X ( z)<br />

= =<br />

D(<br />

z)<br />

( z − p )( z − p )( z − p )... (5.4)<br />

1<br />

2<br />

3<br />

where z 1<br />

, z2,<br />

z3<br />

... are called the zeros as which make X(z) =0; <strong>and</strong> p<br />

1<br />

, p2,<br />

p<br />

3 , ... are the poles as which make X(z) ® ¥.<br />

Zeros <strong>and</strong> poles are either a real number or complex conjugate pairs.<br />

The Wake<br />

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