PXI 6356 Simultanous analog in w/ External clock source - Capture time delay

[LVElite]

Hello,

We are interested in acquiring simultanous data using an external clock source (in this case a 1MHz sync signal). We are trying to figure out what is the amount of jitter or time delay between the external clock source and the time the samples are captured when performing simultanous A/D acquisition.

Thanks in advance for your help.

[Wee-Bey]

How are you connecting your external clock source to your device? What is the external source? You can estimate this by guessing what the delay is from the line, and from the stats of the PXI.

[LVElite]

We do not have the hardware yet. At the moment we are trying to make a purchase decision. We will be using an Agilent function generator to generate a TTL level sync signal. I am not sure how we'll be connecting to the generator. I am assuming we can either connect to a PFI input of the card or a PXI 6682 (GPS Timing and Synchronization card) we plan on purchasing to timestamp the samples.

Which method would be preferrable? What would the delay be for that method?

Thanks

[LVElite]

To add more details.. We'll be using the external sync signal as the AI Sample Clock timebase routed via the PFI input. So basically what we're trying to figure out is whats the delay between the time a rising/falling edge appears at the PFI input to the time the samples are simultanously captured.

[Josh_B1]

Hi LVElite,

National Instruments does not specify the delay between the arrival of a pulse on a PFI line and when the time the samples are captured when the PFI line is used for triggering. Is there a reason you are using the Agilent function generator as opposed to your PXI 6682? 

Regards,

Josh Brown

[Josh_B1]

Hi LVElite,

I forgot to share the X series user manule with you.

http://www.ni.com/pdf/manuals/370784c.pdf

If you go to page 8-2 you will see the section on using the PFI line for triggering.

Regards,