Fourier Transform in Simulink

Hello,

I'm simply trying to add up an arbitrary number of sine waves and output the frequency chart with the blocks below:

the matlab function is to perform the fftshift:

function y = fcn(u)

y = fftshift(u)
size(y)
end

But the output of the array plot doesn't seem to make sense, as I've chosen 10 Hz and 20 Hz within the Sine Wave block:

The output of the array plot I would suspect should show peaks at both 10 Hz and 20 Hz, but displays something I'm not quite understanding:

Does anyone have any suggestions on something I'm simply missing here?

[Nikhil Sonavane]

Can you share your Simulink model so that it is easier for me to reproduce your problem?

[Zjuv9021]

Please see attached.

Answer 1

[Ridwan Alam]

Change the Samples per frame property on the Sine Wave block:

https://www.mathworks.com/help/dsp/ug/transform-time-domain-data-into-the-frequency-domain-using-the-fft-block.html

Answer 2

[Nikhil Sonavane]

The Matrix Block used isn't giving desired results as the Sum over field is not configured properly. Change the Sum over field to Specified dimension and select the Dimension as 2. For more information execute the following command in MATLAB command window and execute it-

openExample('dsp/TransformTimeDomainDataIntoFrequencyDomainExample')