create a function from temperature data

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susana martins
susana martins on 30 Sep 2022
Answered: Star Strider on 30 Sep 2022
I have dataset from temperature and i would like to create a trignometric function to describe daily temperature variation. Is it possible?

Answers (3)

KSSV
KSSV on 30 Sep 2022
Read about interpft

Walter Roberson
Walter Roberson on 30 Sep 2022
If you have the Curve Fitting Toolbox, you can use curvefitter() https://www.mathworks.com/help/curvefit/curvefitter-app.html . Or for before R2022a use cftool() . You would select "Sum of sine" and 1 term. This would fit your data as a single sine wave with some amplitude, some frequency, and some phase offset.
If you do not have the Curve Fitting Toolbox, you could also use fft() and pick out the largest peak; the location would tell you the primary frequency, and the magnitude and imaginary component there would estimate the amplitude and the phase (but you would have to go back and recompute those to take into account the other frequencies.)

Star Strider
Star Strider on 30 Sep 2022

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