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Suppose a DT signal x[n] satisfies
 
Suppose a DT signal x[n] satisfies
  
1. x[n] is periodic and period N=8.
+
1. x[n] is periodic and period N=6.
  
2. <math>\sum_{n=0}^{7}x[n]=5</math>
+
2. <math>\sum_{n=0}^{5}x[n]=5</math>
  
3.<math>a_{k+3} = a_k</math>
+
3.<math>a_{k+2} = a_k</math>
  
 
Find x[n].
 
Find x[n].
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Answer:  
 
Answer:  
  
from 1 we deduce that x[n]= <math>\sum_{n=0}^{8}a_k e^{-jk \frac {\pi}{4} n}=5</math>
+
from 1 we have that x[n]= <math>\sum_{n=0}^{5}a_k e^{-jk \frac {\pi}{3} n}</math>
  
from 2 we have <math>a_0 = avg = \frac {5}{8}</math>
+
from 2 we have <math>a_0 = avg = \frac {5}{6}</math>
  
from 3 we have <math>a_3 = a_6 = a_0 = \frac {5}{8}</math>
+
from 3 we have <math>a_2 = a_4= a_0 = \frac {5}{6}</math>

Revision as of 11:58, 25 September 2008

Suppose a DT signal x[n] satisfies

1. x[n] is periodic and period N=6.

2. $ \sum_{n=0}^{5}x[n]=5 $

3.$ a_{k+2} = a_k $

Find x[n].



Answer:

from 1 we have that x[n]= $ \sum_{n=0}^{5}a_k e^{-jk \frac {\pi}{3} n} $

from 2 we have $ a_0 = avg = \frac {5}{6} $

from 3 we have $ a_2 = a_4= a_0 = \frac {5}{6} $

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Recent Math PhD now doing a post-doctorate at UC Riverside.

Kuei-Nuan Lin