Created on 2009-06-26 22:52:00

Question:

I am running a test where it’s required to report theresults in dBμV, but the APsoftware only has units of dBV. How can I report the test results in dBμV?

Answer:

There are two options available.

1) Simply run the test using units of dBV and manually add 120 dB to the results, to convert from dBV to dBμV.

Voltage levels in dB are calculated using the equation

dBre Vref= 20log(V/Vref)

where Vref is the reference voltage. In the caseof dBV, Vref = 1.0 V and for dBμV,Vref = 1.0 x 10^-6 V. Therefore, the conversion factor between dBV and dBμV is 20log(10⁶) = 120 dB.

2) Use the dBr references. AP audio analyzers are equipped with two dB reference controls, dBrA and dBrB, that can be used to set arbitrary decibel reference values. For example, you could set dBrA to 1.0 μV, as shown below and then select dBrA as the units in the Analyzer meter or Function meter. In the figure below, the Analog Generator has been set to 1.0 mV, and the analog inputs have been set to GenMon, resulting in a level reading of +60 dBrA (or 60 dBµV; = 20log(1.0/0.001)).

slx 001-00-004662
jb