How to find "Square power spectral density SPSD"

[tronoh]

Deat Sir

I read in a reaserch paper where the author first get power spectral density of the measured signal and then he get square of the power spectral density. (His results are shown in attachments). I can get the PSD of my signal but I could not understand how to get the SPSD!!. Can you please assist me in this matter. Should I just get square of the amplitude values (i.e 20 Hz component has 0.2 A amplitude in PSD, Will it become 0.4 A in SPSD?)

I shall be thankful to you for your attention and consideration.

Kind Regards

Urfee

[craigc]

Hi,

I have a very old version of labview so cannot open your VI, however I think from the description you would just use the PSD vi located in the Signal Processing -> Waveform Measurements Pallette and square the results.  0.2^2 is 0.04 so yes you would get a lower dB then id you didnt square your results 🙂  As he states he simple squared his results to fit within a desired dB range.

Craig

[tronoh]

Dear Sir

Thank you for your reply. So you mean that any amplitude value at specific frequency should be squared? Like in the attachemnet aplitude of SPSD is shown to be 5 dB. Then amplitude of PSD will be square root of 5 i.e 2.23 dB. I am right?

[craigc]

Hi,

I have no direct experience with this field but from what you have provided I believe this to be correct.

As suggested by this statement in your post.

"Finally the Squared Value of the Averaged PSD (SPSD) has been computed to fit the magnitude scale between 0 to -120 db"

Craig