to perform DFT on a simple sine wave

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ajayreddybireddy

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hello,

anybody please help me
how to perform DFT on a sine wave of freq about 1000hz, without using MATLAB FFT function.

please help me
I am new to MATLAB!!!
 

You can write the algorithm; the DFT equation which is:

X(W) = x(0)*exp(-j*0*W)+ x(1)*exp(-j*1*W)+..... untill N-1 where N is the number of samples after which the spectrum is periodic (sampling frequency). In this case you'll take only two time samples one of them is zero valued that result having an impulse at frequency of 1000 Hz.
 
thank you Sir,

from provided equation I can't do the implementation.

Sin(2*pi*1000*t); sampling freq=4000, is the sine wave on which I am trying to implement DFT equation without applying FFT matlab function.


can you please provide me the concerned code.

please Sir....
 

check mathworks website (MATLAB central), I don't have a code currently.
 

anyway I got solution for this..
just see the below code


N=400;
n=0:N-1;
f1=1000;
fs1=8000;
x=sin(2*pi*(f1/fs1)*n);
y=fft(x);
z=abs;
for k=0:N-1
for n=0:N-1
X(n+1)=x(n+1)*exp(-j*2*pi*k*n/N);
end
Xk(k+1)=sum(X);
end
Xk
l=abs(Xk);
subplot(3,1,1);
plot(l);
subplot(3,1,3);
plot(z);
title('using fft function')
 

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