6674T Frequency Measurements Accuracy

Updated May 3, 2018

Reported In

Hardware

  • PXIe-6674T

Driver

  • NI-Sync

Issue Details

What is the accuracy of the of frequency measurements my 6674T is reading?

Solution

If you override the backplane clock, then you will be inheriting the 6674T's OCXO accuracy, which is listed in the specifications document.

Here are the ways to override:

  1. Make an niSync call to connect Oscillator to PXI_Clk10_In
  2. Make an niSync call to connect Oscillator to CLK_Out and also cable CLK_Out to the 10 MHz in connector on the chassis.

If you're not doing either of the methods above, but have some other 10MHz connected to the 10 MHz in connector on the chassis. Then the frequency measurement will inherit the accuracy of that clock.

If you're not overriding then your accuracy is the accuracy of the PXI chassis backplane clock. Check the specifications of your chassis to find this accuracy, it is likely 25 ppm. If you're accuracy is within this 25 ppm, then it is in spec.

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