Line 14: Line 14:
  
 
----
 
----
 +
 
=== Answer 1  ===
 
=== Answer 1  ===
 +
  
Using the table and a time shift
+
<br> --[[User:Ssanthak|Ssanthak]] 12:51, 20 April 2011 (UTC)  
 
+
&nbsp;X(w) = pi[u(w+6pi-pi/2) - u(w-6pi-pi/2)]
+
 
+
&nbsp;&nbsp; &nbsp; &nbsp; &nbsp;= pi[u(w+11pi/2) - u(w-13pi/2)]
+
 
+
<br>
+
 
+
Thus the signal is band limited wm = 13pi/2, so ws &gt; Nyquist Rate = 2wm = 13pi
+
 
+
Since T = 2pi/ws
+
 
+
T &lt; 2pi/13pi = 2/13
+
 
+
  
 +
:TA's comment: There are a couple of mistakes here. First, the factor <span class="texhtml">1 / 2π</span> is missing when applying the multiplication property of the FT. There is also a mistake when applying the frequency-shift property of the FT, since the result should be a spectrum which is shifted to the left and not to the right. The condition on the sampling frequency is incorrect too which was the result of considering the given signal as a real signal ,i.e. a signal that has an even symmetric spectrum (or considering it as pure imaginary signal that has odd symmetric spectrum).
 +
Ooops that was the answer to the next question I moved it there.
  
T &lt; 2/13 in order to recover the orginal signal
+
--[[User:Ssanthak|Ssanthak]] 12:42, 21 April 2011 (UTC)
  
<br>
 
--[[User:Ssanthak|Ssanthak]] 12:51, 20 April 2011 (UTC)
 
:TA's comment: There are a couple of mistakes here. First, the factor <math>1/2\pi</math> is missing when applying the multiplication property of the FT. There is also a mistake when applying the frequency-shift property of the FT, since the result should be a spectrum which is shifted to the left and not to the right. The condition on the sampling frequency is incorrect too which was the result of considering the given signal as a real signal ,i.e. a signal that has an even symmetric spectrum (or considering it as pure imaginary signal that has odd symmetric spectrum).
 
  
 
=== Answer 2  ===
 
=== Answer 2  ===

Revision as of 08:42, 21 April 2011

Practice Question on sampling and reconstruction (related to Nyquist rate)

The signal

$ x(t)= e^{-j \pi t }\frac{\sin (3 \pi t)}{\pi t} $

is sampled with a sampling period T. For what values of T is it possible to reconstruct the signal from its sampling?


Share your answers below

You will receive feedback from your instructor and TA directly on this page. Other students are welcome to comment/discuss/point out mistakes/ask questions too!


Answer 1


--Ssanthak 12:51, 20 April 2011 (UTC)

TA's comment: There are a couple of mistakes here. First, the factor 1 / 2π is missing when applying the multiplication property of the FT. There is also a mistake when applying the frequency-shift property of the FT, since the result should be a spectrum which is shifted to the left and not to the right. The condition on the sampling frequency is incorrect too which was the result of considering the given signal as a real signal ,i.e. a signal that has an even symmetric spectrum (or considering it as pure imaginary signal that has odd symmetric spectrum).

Ooops that was the answer to the next question I moved it there.

--Ssanthak 12:42, 21 April 2011 (UTC)


Answer 2

Write it here

Answer 3

Write it here.


Back to ECE301 Spring 2011 Prof. Boutin

Alumni Liaison

Questions/answers with a recent ECE grad

Ryne Rayburn