What is the unit of power spectrum for a voltage signal?
What is the unit of power spectrum for a voltage signal?
(OP)
I've an Agilent 35670A Dynamic Signal Analyzer. A signal is attached to Channel-1. The unit of the signal measured by the analyzer is as follows:
Time Capture (time domain): Volt (V)
Linear Spectrum (frequency domain): Volt-RMS (Vrms)
Power Spectrum (frequency domain): Volt-RMS (Vrms)
However, some online articles, for example the following:
htt p://zone.n i.com/refe rence/en-X X/help/371 361D-01/lv anls/power _spectrum/
... show that for a voltage signal, the unit of the power spectrum of the signal is Volt-RMS squared (Vrms^2).
Which one is correct?
Thanks.
Time Capture (time domain): Volt (V)
Linear Spectrum (frequency domain): Volt-RMS (Vrms)
Power Spectrum (frequency domain): Volt-RMS (Vrms)
However, some online articles, for example the following:
htt
... show that for a voltage signal, the unit of the power spectrum of the signal is Volt-RMS squared (Vrms^2).
Which one is correct?
Thanks.





RE: What is the unit of power spectrum for a voltage signal?
This confusion came up long ago with photodetectors when looking at noise performance. Photodetectors convert convert optical power to current directly, so this is a square law conversion. To keep the relationship linear the wrong units are typically displayed.
John D