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Cornel19-Tanzanite
19-Tanzanite
July 3, 2025
Question

How to take DFT of this signal using Prime built in dft function?

  • July 3, 2025
  • 3 replies
  • 631 views

 

Hi,

How to take the discrete fourier transform of this signal and plot the magnitude vs frequency and phase vs frequency by using Mathcad Prime dft built in function?

Cornel_1-1751551646272.png


Suppose that we will sample this signal at 4 time per second (fs=4Hz) from t=0 to t=3/4.



I have tried something manually, but how to show phase plot I do not know right now...

Cornel_2-1751551943114.png

Cornel_3-1751551962909.png

 

Prime 10 file attached.

3 replies

W
Werner_E25-Diamond I
25-Diamond I
July 3, 2025

You have to use "arg", not "angle"

You may want to lookup these functions in the help

P
ppal_25568718-Opal
18-Opal
July 3, 2025

ppal_0-1751583231021.png

 

ttokoro
21-Topaz I
ttokoro21-Topaz I
21-Topaz I
July 4, 2025

image.pngimage.png

t.t.
C
Cornel19-TanzaniteAuthor
19-Tanzanite
July 4, 2025

 

Could you attach the mathcad prime 10 file?

 
ttokoro
21-Topaz I
ttokoro21-Topaz I
21-Topaz I
July 4, 2025

 I useally use Prime 11. So, copy and past one by one from 11 to 10. 

Attach it.

Magnitude of spectrum must divide by 400, the number of data used to dft.

A half of its value is the n-th value of the spectrum. Another of harf is at the bottom of spectrum data, such as DC, 1st, 2nd, ..... 2nd, 1st.  

Phase of signal seems to valid for spectrum with magnitude more than 10 or 20 in this case.

t.t.
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