#### Mustaine

##### Member level 1

Hello friends why matlab gives the magnitude fourier transform of cosine as 250.

is not it should be 1/2 according to the equation below.

thanks

this is the matlab code:

i tried to do that on simulink by changing the frequency as 1k .

type of the spectrum power and the unit is watts but i get the magnitude as 0.25.

is that value correct

also the magnitude is varied by the sample time why is that

thanks in advance.

is not it should be 1/2 according to the equation below.

thanks

--- Updated ---

this is the matlab code:

Code:

```
Tsample = 1/50;
t = 0:Tsample:10-Tsample;
x = cos(2*pi*10*t);
figure
plot(t,x)
xlabel('Time (seconds)')
ylabel('Amplitude')
y = fft(x);
fsample = 1/Tsample;
n = length(x);
fshift = (-n/2:n/2-1)*(fsample/n);
yshift = fftshift(y);
figure
stem(fshift,abs(yshift))
xlabel('Frequency (Hz)')
ylabel('Magnitude')
```

--- Updated ---

i tried to do that on simulink by changing the frequency as 1k .

type of the spectrum power and the unit is watts but i get the magnitude as 0.25.

is that value correct

also the magnitude is varied by the sample time why is that

thanks in advance.

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