What is the unit of the result of spectrogram?

Hi, all. I want to ask about the unit of the result of spectrogram function.

The code I use is below:

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window=hann(2048);

[s,f,t] = spectrogram(y_total,window,1024,2048,2000);

% y_total is the mV data with 2kHz smapling rate.

s = abs(s);

sum_of_power = s(1,:) + s(2,:) + s(3,:) + s(4,:);

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I'm using the spectrogram function to know the changes of powers in specific frequency range. The result is good, but the problem is that I don't know the unit of the value 's'. Someone told me that the unit might be the 'Hz/mV^2', or others told me that 's' is the normalized value, so there is no unit.

Is there anyone who can tell about the unit of the result?

Thank you.

Answer 1

[Gautam Mohan]

Hi Jeong,

The spectrogram units are power/frequency, as it computes the power spectral density.