Hello, I have a couple (hopefully) general questions about using an external reference clock on our USB 5132 digitizer. We want to lock it to the other oscillators in our system, all of which are presently locked to one 10 MHz reference. If I connect our existing 10 MHz reference to the PFI1 input, my questions are: 1. Is the 5132 now locked to our system? Or, do we need to specifiy in the setup software that we want to override the 5132's internal reference and rely entirely our external reference? 2. In order to have the best possible lock, do we need to tell the 5132 to sample at a frequency that is evenly divisible by 10 MHz (e.g. 20 MHz, 10 MHz, 5 MHz, 2 MHz, etc.)? Similarly, are we worse off if we want to sample at say, 13 MHz? Thanks for any thoughts. Best regards, Penny

Hello Penny, You will need all three. The "sampleScopeSession.Timing.SampleClockTimebaseRate = 1.0e7;" is specifying the rate of the SampleClockTimebase Source. The only piece of the code which you will not need is the "sampleScopeSession.Timing.SampleClockTimebaseMultiplier " because your device does not support RIS. Regards, Izzy O. Applications Engineer National Instruments www.ni.com/support

High-Speed Digitizers

external reference for USB 5132

Solved!

Author

Hi Izzy,

OK thanks! I will go ahead and specify the 10 MHz to the card.

-Penny

Message 11 of 11

(2,584 Views)

High-Speed Digitizers

external reference for USB 5132

Re: external reference for USB 5132