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*Under construction --[[User:zhao148|Zhao]]
 
*Under construction --[[User:zhao148|Zhao]]
 
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Q1. Show that the DTFT of time-reversal, <math>x[-n]</math>, is <math>X(-w)</math>  
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Q1. Show that the DTFT of time-reversal, <math>x[-n]\,\!</math>, is <math>X(-w)\,\!</math>  
  
 
* [[ECE438_Week13_Quiz_Q1sol|Solution]].
 
* [[ECE438_Week13_Quiz_Q1sol|Solution]].

Revision as of 11:09, 17 November 2010


Quiz Questions Pool for Week 13

  • Under construction --Zhao

Q1. Show that the DTFT of time-reversal, $ x[-n]\,\! $, is $ X(-w)\,\! $


Q2. Consider the discrete-time signal

$ x[n]=2\delta[n]+5 \delta[n-1]+\delta[n-1]- \delta[n-2]. $

a) Determine the DTFT $ X(\omega) $ of x[n] and the DTFT of $ Y(\omega) $ of y[n]=x[-n].

b) Using your result from part a), compute

$ x[n]* y[n] $.

c) Consider the discrete-time signal

$ z[n]=\left\{ \begin{array}{ll}x[(-n)\mod 4],& 0\leq n < 3,\\ 0 & \text{else }\end{array} \right. $.

Obtain the 4-point circular convolution of x[n] and z[n].

d) When computing the N-point circular convolution of x[n] and the signal

$ z[n]=\left\{ \begin{array}{ll}x[(-n)\mod N],& 0\leq n < N-1,\\ 0 & \text{else }\end{array} \right. $.

how should N be chosen to make sure that the result is the same as the usual convolution between x[n] and z[n]?

  • Same as HW8 Q3 available here.

Q3.


Q4.


Q5.


Back to ECE 438 Fall 2010 Lab Wiki Page

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Sean Hu, ECE PhD 2009