Power Spectral Density Units (Sound and Vibration Toolkit)

[rcaeti]

Ultimately, I need to obtain sound pressure data from a microphone in the form of a PSD with units of dB / Hz.  Using the Broadband FFT example  VI from the toolkit as a basis for my work, I'm trying to obtain the Power Spectral Density.  My confusion lies with the units.  When I switch the dB switch on, it displays the units as dB / sqrt(Hz) (I've never seen a PSD displayed like this and according to the LabVIEW manual, this is the amplitude spectral density, not the power spectral density).  For my project, I need the standard PSD units of just dB / Hz.  Interestingly enough though, with the dB switch off, I'm able to choose units of either EU^2 / Hz or EU / sqrt(Hz)

How can I obtain the units of dB / Hz using this VI?

Thanks,

Ryan

[Frank-L]

rcaeti,

This is Frank L, the Applications Engineer from National Instruments that you spoke with on the phone the other day about this issue. I am currently looking into whether or not this example has an incorrect display as you suspected in the previous phone conversation and am getting assistance from the product support engineer. I will update you with more information as I receive them form the PSE on this issue and will provide this data as soon as I get more information.