I am using NI4432 interface for measuring sound pressure with a piezoelectric pressure sensor (106B51), but noticing high level of background noise as observed by some others on this forum. I then tried using NI9250 instead, and the background noise level was reduced. However, in this case I found I had a large DC offset.
I can remove this by post-processing using highpass filter (in Matlab), and then the results looked reliable when using with a 94dB/114dB calibrator.
Why am I seeing this offset? Is there any hardware settings that need changing?
A small overview of settings are shown attached, the Excitation Value 2.000mA is needed for the pressure sensor.
