How to plot power spectrum density (db/hz) as a function of time ?

I want to plot power spectral density F(time) of my signal. I can plot a spectogram but need help how to just plot the power spectral density as a function of time?

Answer 1

[Sai Charan Sampara]

Power spectral density is a function of frequency. It gives the power distribution of a signal as a function of its frequency. The spectrogram contains the frequency components of the signal. The square of the absolute values of frequency components (spectrum values) gives power spectral density. Power is energy per unit time. So the power spectral density is only a function of frequency and does not have any relation to time.