PXIe-4331 Noise Increasing with Sampling Rate

Updated May 29, 2019

Reported In

Hardware

  • PXIe-4331
  • PXIe-4330

Issue Details

When increasing the sampling rate on my PXIe-4331, the noise increases. Is this expected or is this a HW issue? How do I fix it?

Solution

PXIe Card Specifications:

Based on the PXIe-4330/4331 Specifications sheet, the card's input noise can be magnified by increasing the sampling rate (fs). Compare the measured noise with these specifications and determine whether the amplification in noise is expected.

Other Sources of Noise:

The environment in laboratories can often contain AC noise, such as a 60 Hz signal from flourescent light bulbs or a nearby power line. Performing a quick FFT on the noisy signal could help identify the source of the noise.

Potential Solutions:

A low-pass RC filter could eliminate this AC noise or even sample averaging could help reduce the impact of powerline noise. If lights are the source, acquiring data with the lights turned off could also be a simple solution. Make sure to consider all safety protocols before doing so.

Additional Information

According to the PXIe-4330/4331 specification sheet, this PXIe card must be sampled in multiples of 100 S/s if the requested sampling rate is above 100 S/s.