Hello,
I am trying to use a PCIe-6351 to record the arrival times of a fast TTL pulse stream (generated by an Excilitas/Elmer Perkin APD). The TTL pulses are 2.5 volt amplitude, 20 ns duration, with a gauranteed dead time of 50 ns between pulses. I am trying to use the the Count Edges function, with the 100MhzTimebase as the input terminal and the input to counter 0 (PFI8) as the sample clock. After a few seconds of acquiring data at 100 Mhz, the application throws the following error (-201314):
"Multiple Sample Clock pulses were detected within one period of the input signal"
I had thought that because there is 50 ns dead time between pulses, multiple pulses would never arrive within a single clock cycle of the 100 Mhz timebase. Is there any way this might not be the case? Alternatively, is it possible that the counter is triggering on some jitter around the edges of the pulses? If so, is there any way to filter such high frequencies without losing the 20 ns pulses?
I have read through the forums for similar problems with photon detectors, but have not been able to resolve this issue. Thank you for the help.
Matthew Bakalar