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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 />

Table 5.3 Summary of properties of 2 nd order systems<br />

<strong>System</strong> function About Zeros About Poles<br />

Transfer<br />

function<br />

H(z)<br />

Zeros:<br />

When z =Zero, H(z) = 0<br />

Poles:<br />

When z =Pole, H(z) = ∞<br />

Frequency<br />

response<br />

|H(Ω)|<br />

When Ω = q<br />

1 |H| = min<br />

If r 1 =1 <strong>and</strong> Ω = q , |H|=0<br />

1<br />

(reject frequency)<br />

When Ω = q<br />

2 ,<br />

|H| = max (peak gain)<br />

Problems<br />

Q5.1 Find the Z-transform for a digital signal given by<br />

↑<br />

2<br />

( 0.35) ,( 0.35)<br />

x[<br />

n]<br />

= [1, 0.35,<br />

, ...]<br />

3<br />

<strong>and</strong> find the Z-transform if the signal has been changed <strong>to</strong><br />

↑<br />

2<br />

( 0.35) ,( 0.35)<br />

x[<br />

n]<br />

= [1, 0.35,<br />

, ...]<br />

3<br />

Q5.2 A digital signal is described as<br />

x[<br />

n]<br />

=<br />

⎧<br />

⎨<br />

0<br />

⎩( 0.9)<br />

n<br />

for<br />

for<br />

n < 0<br />

n ≥ 0<br />

Find the sum ∑ ∞<br />

=0<br />

n<br />

x [ n]<br />

<strong>and</strong> the Z-transform of the signal.<br />

Q5.3 Expend the following z-transform functions as power series in<br />

at n=1):<br />

a)<br />

b)<br />

c)<br />

X ( z)<br />

X ( z)<br />

X ( z)<br />

1<br />

= z − 0.6<br />

z<br />

= z + 1.2<br />

z + 1<br />

= z −1<br />

−1<br />

z , <strong>and</strong> find their first five sample values (starting<br />

84<br />

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