HOW to solve x(n) = {1, 1, 1, 1, 1, 1, 0, 0} about dft

HOW to solve x(n) = {1, 1, 1, 1, 1, 1, 0, 0} about dft

Answer 1

[Srija Kethiri]

Hi seung,

I understand that you want to find the Discrete Fourier Transform of x(n)

Please refer to the below pointers to know more about the same:

• You can use the MATLAB function “fft” to compute the Discrete Fourier Transform of a variable “x”.
• The command “Y = fft(x)” computes the Discrete Fourier Transform (DFT) of "x" using a fast Fourier transform (FFT) algorithm.
• You can refer to the below documentation link for more information on the MATLAB function “fft”- https://www.mathworks.com/help/matlab/ref/fft.html

Hope this helps!

Answer 2

[Arnab]

compute the 8 point dft of x(n)=[1 1 1 1 0 0 0 0]

[Walter Roberson]

x = [1 1 1 1 0 0 0 0].'

x = 8×1

1 1 1 1 0 0 0 0

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F = fft(x)

F = 
   4.0000 + 0.0000i
   1.0000 - 2.4142i
   0.0000 + 0.0000i
   1.0000 - 0.4142i
   0.0000 + 0.0000i
   1.0000 + 0.4142i
   0.0000 + 0.0000i
   1.0000 + 2.4142i

y = [sym(4), 
    1-(sqrt(sym(2))+1)*1i,
    sym(0), 
    1-(sqrt(sym(2))-1)*1i,
    sym(0)
    1 + (sqrt(sym(2))-1)*1i,
    sym(0),
    1 + (sqrt(sym(2))+1)*1i]

y = 

double(y)-F

ans = 
   1.0e-15 *

   0.0000 + 0.0000i
   0.0000 + 0.0000i
   0.0000 + 0.0000i
   0.0000 + 0.1110i
   0.0000 + 0.0000i
   0.0000 - 0.1110i
   0.0000 + 0.0000i
   0.0000 + 0.0000i

Answer 3

[Raju]

x[n]=[1,1,1,1,1,1,0,0]

[Walter Roberson]

I do not understand how this answers the question that was asked?