Power Spectral Density Estimates Using FFT
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I used PSD through FFT and the numbers in my plot (Y-axis) are not less than 1 as I expected to see in PSD result. I attached the sample function and the plot. Is something wrong with my function that should be changed?
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/170896/image.bmp)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/170897/image.jpeg)
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vijaya lakshmi
2018-3-22
Hi Mo,
To compute the power spectral density using the FFT function, the absolute value FFT output has to be squared and scaled by (1/length(data))*(1/Fs) where Fs is the sampling frequency. This result is then converted to decibels.
I observe that you haven't converted the result in decibels.This might be causing to the numbers along y-axis to be greater than 1.
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