# Interpreting a normalized Power Spectral Density (PSD)

I am using software to produce power spectral density (PSD) plots of time-series (voltage versus time). Unfortunately, the units of the produced plots are alien to me. I'm used to reading and interpreting PSD's in more common, "tangible" units like dBm/Hz or W/Hz, however these plots are described as:

Returns a PSD in $$dB$$ units that is normalized and divided by frequency bin width (i.e. it is normalized to the time-integral squared amplitude of the time domain and then divided by frequency bin width).

How is a PSD in units of dB to be interpreted, and what is the purpose of "normalizing to the time-integral squared amplitude of the time domain"? No further context is provided.

• What library are you using? Mar 29, 2021 at 22:20