(h[n] and H(z))
(h[n] and H(z))
Line 4: Line 4:
  
 
=== h[n] and H(z) ===
 
=== h[n] and H(z) ===
<br><br>
+
<br>
  
 
We obtain <math> h[n] </math> by finding the response of <math> x[n] </math> to the unit impulse response (<math> \delta[n] </math>).
 
We obtain <math> h[n] </math> by finding the response of <math> x[n] </math> to the unit impulse response (<math> \delta[n] </math>).
Line 12: Line 12:
  
 
<math> \,\ H[z] = \sum_{m=-\infty}^\infty h[m] * Z</math><sup>(<math>-m</math>)</sup><br><br>
 
<math> \,\ H[z] = \sum_{m=-\infty}^\infty h[m] * Z</math><sup>(<math>-m</math>)</sup><br><br>
<math> \,\ H[z] = \sum_{m=-6}^{5}Z</math><sup>(<math>-m</math>)</sup>
+
<math> \,\ H[z] = \sum_{m=-\infty}^{\infty} (5*\delta[n-5] + 6*\delta[n+6]) * Z</math><sup>(<math>-m</math>)</sup>
 +
 
 +
By the sifting property, this sum equals:<br>
 +
<math> \,\ H[z] = 5*Z</math><sup>-5</sup><math> \,\ + 6*Z</math><sup>6</sup>

Revision as of 16:57, 25 September 2008

Define a DT LTI System

$ \,\ x[n] = 5*u[n-5] + 6*u[n+6] $

h[n] and H(z)


We obtain $ h[n] $ by finding the response of $ x[n] $ to the unit impulse response ($ \delta[n] $).

$ \,\ h[n] = 5*\delta[n-5] + 6*\delta[n+6] $

$ \,\ H[z] = \sum_{m=-\infty}^\infty h[m] * Z $($ -m $)

$ \,\ H[z] = \sum_{m=-\infty}^{\infty} (5*\delta[n-5] + 6*\delta[n+6]) * Z $($ -m $)

By the sifting property, this sum equals:
$ \,\ H[z] = 5*Z $-5$ \,\ + 6*Z $6

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