PXI-5122 CLK IN CLK OUT problem

[indianyy]

Hi, all:

       I need to use 5122 to digitize a 5000 HZ square waveform from a function generator. However, because of the clock from the function generator and the clock from 5122 are not phase locked, the digitized signal has some problem, if I use 100MHz sampling frequency, after I reshape the output data of 5122 into a two dimensional matrix (20000*250, 20000 is the length of one square waveform, total 250 waveforms), the first square waveform and the 250th square waveform are 3-8 points shifted. This shift is randomized.

      To fix the problem, I try to use the CLK OUT of 5122 to control function generator, however, there is no output from CLK OUT.

      Then I tried to use the function generator output to control 5122 through CLK IN of 5122, the 5122 works as before, I do not see any difference so I can not see if 5122 used external clock. The 3-8 points shift is still there.

      Could somebody give me a hint?

Thanks.

hui

[Jim_S]

Hello Hui,

After reading over your post, it looks like you want to sync your function generator to your PXI-5122. Is your function generator a PXI device and which one is it? Depending on which one you have in your system, we can utilitize the T-Clk functionality. The T-Clk is our way of synchronizing two separate devices in a PXI chassis. Here is a DeveloperZone article describing it in more detail.

The cards that have this capability must have the Synchronization and Memory Core (SMC) chip in it. In order to see if your hardware does, here is a KnowledgeBase article with that information.