Help me draw two signals from the one in graph

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konarkk

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Though this is a basic but I m getting confusion to draw following two signal from below signal



X1[n] = X [3n – 4]
X2[n] = X[-(n+8)/4], please give detail explanation
 

Re: need help

hello konark the second question seems to be unclear, can u please correct it once again

Added after 5 minutes:

for these type of signals the following is done:
1) Time Sifting
2) Scaling

therefore for first question x1=x[3n-4];
1) x[n-4] = { 0,-3,0,1,2,-3,3,-1}
2) x[3n-4]=(0,1,3}
 

Re: need help

In 2nd que the i/p is x[-(n + 8)/4]

Added after 1 minutes:

the no is eight
 

Re: need help

in the second equation, now
x[-(n+(8/4))] =x[-(n+2)] = x[-n-2]

therefore x(-n) yields the mirror image of x, therefore
x(-n) = {-1,3,-3,2,1,0,-3} for n=0 for value 2
now x(-n-2) yields shifting left the signal two times
therefore now n=0 for value 0


if any correction please intimate me also
 

Re: need help

Oh in 2nd que 8/4 is not there instead (-n + 8 )/ 4
 

Re: need help

ya sorry for that mistake. ok i have got the answer, but i dont know how much i am sure about it.

x(-n) ={-1,3,-3,2,1,0,-3}, n is 0 for value 2
x(-n+8) = {0,0,0,0,0,-1,3,-3,2,1,0,-3} that is x(-n) is shifted right 8 times.

now scaling operation, as it is scaling by (1/4), the signal expands a lot

x[(-n+8)/4] = {0,.,.,.,0,.,.,.,0,.,.,.,0,.,.,.,0,.,.,.,0,.,.,.,-1,.,.,.,3,,.,.,.,-3,,.,.,.,2,,.,.,.,1,,.,.,.,0,,.,.,.,-3}

where . represents 0 itself.

Added after 1 minutes:

those smileys are 8
 

    konarkk

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need help

just substitute various values for n.
an example:

put n=0 in equation 1.
.: x1[0]=x[3*0 -4]=x[-4]=0(because in the original signal x[-4] does not exist).

next, for n=1,
x1[1]=x[-1]=1(from the figure)

and so on.

carry out the similar procedure for the second equation also.

also check out that for the 2nd equation you will get fraction values. omit them. n must only be an integer.

regards,
amrith.s
 

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