Magnitude conversion fro decibels after spectral measurements

[Vibronator]

I am using LabView to monitor the vibration of a turbine system. When I dump my spectra to a file, the magnitude is in decibels, but what is the reference voltage labview is using? I would like to convert the decibels back to voltage with DB=10Log(V/Vo), but I don't know what Vo is? is it 1V?. Thanks!

[Viper]

for dBuV Vo is 1 uV

for dBmV V0 is 1 mV

Wikipedia has a good article on dB

[Viper]

Actually the question is what voltage refernce is your instrument using? Is the instrument using dBuV, dBmV, dBm? LabView just thinks its a double. You need to do the conversion. Log units are tricky because they have no units. dBuV = 20 * log (V/1uV)... the voltage units cancle out so there are no units. That's why google calculator doesn't do dB.

[Vibronator]

I'm not sure what the refernce level is, do you know where to find it? Also I'm not following, what do you mean by a double?

Thanks for the help

[smercurio_fc]

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@Vibronator wrote:

I'm not sure what the refernce level is, do you know where to find it?

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That's based on your measurement setup. If you don't know is there someone else who set it up who can tell you?

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Also I'm not following, what do you mean by a double?

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That is the datatype of the value. Have you done any of the LabVIEW tutorials? This is an extremely basic question.

To learn more about LabVIEW it is recommended that you go through the introduction material, tutorial(s), and other material in the NI Developer Zone's Learning Center which provides links to other materials and other tutorials. You can also take the online courses for free.