How Is the AC Amplitude Accuracy Value for NI Oscilloscopes Interpreted?

Updated Dec 16, 2019

Reported In

Hardware

  • PXI-5105
  • PXIe-5105

Issue Details

In the NI Scope card's specification sheet I'm confused about the value of the AC amplitude accuracy.

For example, on the 30 V range the AC Amplitude accuracy is +/- 4.7%.
  • How is this value interpreted?
  • Is this value related to the measurement or the full-scale range?  

Solution

This specification value is in reference to the input signal, so it is not a constant value. This means that the accuracy of the device varies depending on the signal it is measuring.

This would mean that if you're measuring a 25 V signal the accuracy for that measurement would be +/- 1.175 V, instead of the +/- 1.41 V if the value was a constant in relation to the range of the device.
 

Additional Information

This accuracy is measured at 90 % Full Scale for each input rage.