PXI-4462 sample rate set

[poklad]

Hi!

How can I determine available sample rate for this board? What mean "181.9 uS/s increment" in the datasheet?

Jury

[lis@jiang]

Hi Jury,

I'm assuming you're looking at the 4462 spec sheet?

Your available sample rates range from 1 kS/s to 204.8 kS/s.  181.1 uS/s is the smallest amount you can increment your sample rate.

Thanks for the question,

Lisa

[poklad]

Hi Lisa!

Thank you for answer!

I read 4462 spec sheet.

If 181.9 uS/s mean that available sample rate is:

1000 Hz

1181.9 Hz

1363.8 Hz

... and so on.

Jury

[lis@jiang]

Hi Jury,

The 181.9 uS/s means 181.9 microSamples/second.  Thus, your available rates are [1000, 1.0001819, 1.0003638...] Hz.

Thanks,

Lisa

[poklad]

Hi Lisa!

Thank you for answer!

Is the value 1 kHz and 181.9 microSamples/second precise?

We planed to use PXI-6653 10 MHz oscillator, disciplined by the PXI-6682 GPS for precise time sync. I must know perecise SampleRate if I want to calculate time of the Sample as [SampleNumber]/[SampleRate] with GPS accuracy for long-time record (about 10^4 and more seconds).

Can you say me, how can I calculate the increment of 181.9 microSample/second?

Usually, the sample rate can be obtained as some inner frequency divided on the integer number.

Jury

[lis@jiang]

Hello Jury,

Please find this information in the general DSA manual under Timing and Synchronization, then Sample Rate and Update Rate, Accuracy and Coercion.

Calculating the coerced rate depends a lot on your individual system set up.

Feel free to let me know if you have any specific questions.

Lisa

[lukko]

Hi Lisa,

Did you manage to configure and test the system?

I also would like to obtain precise disciplined clock using PXI-6653 and PXI-6682. I was wondering if you could give me some guidelines about timing and synchronization aspects in LabVIEW. I know right now how to configure the DSAs using DAQmx and how to trigger DSAs using niSync however it is of great unknown how to route the signals between PXI-6682 and PXI-6653 and how to send the timebase from PXI-6653 to DSAs via backplane. I have PXI-4495 as well as 4472 in two different chassis. I also started a separated topic here since this seems to be quite complex issue.

Thanks for help in advance.

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Łukasz

[lukko]

Thanks for help in advance.

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Łukasz

[JaredRo]

lukko,

TylerK provided some great advice in your other thread regarding clock disciplining your multiple remote chassis.  However, you may not actually be able to synchronize your PXI-4495 with your PXI-4472 in one chassis.  The PXI-4472 only supports synchronization by sharing the oversample clock over the backplane PXI star trigger lines.  In your case this would be generated via DDS on the PXI-6653 and routed to the star trigger lines.  The PXI-4495 doesn't have star trigger lines available because it is a hybrid-slot compatible module.  PXI-4495 modules are synchronized by sharing the 10 MHz backplane clock and generating their own oversample clock on board via DDS with a 100 MHz crystal oscillator.  You can still trigger the acquisition from the two cards together, but you may not be able to discipline the clocks together in a single chassis.

[lukko]

Hi Jared,

Thank you for the reply. Could you take a look and suggest something about this issue (link)?

Thanks!

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Łukasz