USB-4432 data acquisition have high level noise

[linda_zhuna]

Hi, we used PXI-4462  for data acquisition when measuring sound pressure. It worked good.

But for make our device more portable, we bought USB-4432, and want to use it instead of PXI-4462. The problem now is that the data obtained through USB-4432 have high level background noise, which didn't happen before. 

The thing is, we used the same program for PXI-4462 and USB-4432, the data from PXI are good, but Data from USB have high level noise. Is there any special set needed for USB-4432? or the data acquisition qualities are different between PXI and USB?

[HeatherBaker]

The noise needs to be quanitified and compared to its specifications to prove that it is operating incorrectly.

[Kurt_Veggeberg]

The voltage range on the USB-4432 is +/- 40 V which is probably too high for the sensitivity of the microphones that you are using which ranges up to 50 mV/Pa which means the signal is typically below 5 V at up to 133 dBA.     The USB-4431 or USB-9234 are better choices, but the NI 446X and NI 449X series are our best choices with multiple gain settings and higher dynamic range.