Phase-locked base clock for FPGA Board in a PXI chassis

[Jakim]

Hi,

I try to measure the frequency of 10 kHz very accurately using an FPGA board (NI PXI-7842R).

As you know, the accuracy of time base is the most important part for this application.

Therefore, I plan to use a 10 MHz reference signal from a time standard.

Currently, the reference signal was connected to the back panel of a PXI chassis and the 40 MHz onboard clock was setup to be phase-locked to this reference clock.

I would like to know if a timing and synchronization module such as PXIe-6674T could increase the accuracy of frequency measurement.

For example, if the module can provide 40 MHz base clock for the FPGA board directly using the 10 MHz reference clock.

Best regards,

Jakim

[blakney]

I am afraid we would need more information to be able to answer your question because it would depend on what type of chassis that you are using to house the FPGA. I will instead give you my understanding of NI timing products that address the PXI / PXIe base clock stability. Hopefully, somebody at NI will chime if I am off the mark.

There are various PXI and PXIe cards that NI provides to replace the PXI (and PXIe) standard clocks stability when compared to the clock that is provided by the various chassis. The PXIe-6674T is one of these that is designed for a PXI Express chassis and will not fit in a PXI chassis. The PXI-6653 is one of a similar line of cards for a PXI chassis. 

Both of the above card provide a 50 part per billion clock rather than the typical 25 part per million (25000 part per billion) clock from a chassis. In other words a 500 times improvement IF all other things are equal.