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Power Spectrum unit: Vrms or Vrms^2 - which one is correct?

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powersys

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power spectrum unit

A signal is attached to Channel-1 of an Agilent 35670A Dynamic Signal Analyzer. 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:
http://zone.ni.com/reference/en-XX/help/371361D-01/lvanls/power_spectrum/
http://www.onosokki.co.jp/English/hp_e/c_support/tech_term/tech_term5.htm
... 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.
 

snafflekid

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unité vrms

I would expect Vrms^2.
 

ark5230

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vrms unit

power = V^2/R, therefore as suggested by snafflekid power is proportional to Vrms^2. Thus for power spectrum this is what is to be used.
Raoof
 

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