When more than one measurement in V/rtHz, REW switches to dBV

Braca

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Hello,

I'm grateful for the possibility to analyse my noise measurements in terms of V/rtHz in REW.

However, when I load more than one measurement stored in V/rtHz and then switch to "All SPL", they are displayed in terms of dBV.
If I then want to calculate e.g. the sum of two noise levels I must convert the dBV values into V/rtHz using sqrt(ENBW) and the perform the RMS summation.

I know that REW is not designed for this kind of analysis but I just wonder if the switch to dBV is deliberate.

Thaks & regards,
Braca
 

John Mulcahy

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There is a V/sqrt(Hz) axis option on the Overlay graph. It is a slightly awkward axis choice to deal with as the displayed results are only valid for measurements captured from the RTA as they include the necessary information to convert to spectral density. Measurements which do not have that data (e.g. log sweep results) show volt figures, though they are still displayed with V/sqrt(Hz) units.
 

Braca

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Thank you very much, it's perfect for my purposes.
 

John Mulcahy

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I have made a change for the next build to add V/sqrt(Hz) in the All SPL graph axis options and changed the unit display in the graph legend so that V/sqrt(Hz) is only shown if the measurement has valid ASD data, otherwise the unit will show volts.
 

Braca

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Splendid, thank you very much!
 
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