What is the Minimum Sound Power Level that can Be Measured Using NI 9234 Card

[AhmedAbdulbaky]

Dears,

i have now a NI 9234 Card and a Micropohne from PCB which can Measure From 15dB to 135dB (and it is IEPE Type) , we Put this Microphone in SemiAnachoic ROOM and we Measure it by the NI 9234 and the Measured Sound Power Level is 30.5 dB , but we Know that the Measured Value Should be Less Than 25 dB ,

So What is the Minimum Sound Power Level that the NI 9234 Can Measure ?

Thanks

[JaredRo]

AhmedAbdulbaky,

Do you have the model number for the PCB microphone you're using?  Also, how are you determining that the measured value should be less than 25 dB?  Also, how are you acquiring data from the NI-9234?  Are you using LabVIEW?

The 9234 should be able to read in signals as long as they are above the noise floor of the device.  A noisier system will have less ability to detect lower voltage signals.  Noise specifications for the 9234 can be found on page 25 of the 9234 User Manual, linked below:

NI 9234 User Manual and Specifications
http://www.ni.com/pdf/manuals/374238c.pdf 

Page 2-1 of the NI Dynamic Signal Acquisition User Manual describes some noise-reduction methods specific to DSA devices.  The link to this document is below:

NI Dynamic Signal Acquisition User Manual
http://www.ni.com/pdf/manuals/371235h.pdf 

 

[dsb@NI]

Is this the same application?

http://forums.ni.com/t5/Dynamic-Signal-Acquisition/Why-does-NI-9234-with-IEPE-microphone-report-39dB...