The fastest cRIO analog input module is the 9201, which samples at 500 kHz, which is equivalent to 2 us intervals. That would not be fast enough to catch your pulse.
The fastest R series board is 750 kHz, which still is not fast enough.
If you built a simple comparator circuit that would convert your pulse to a TTL level signal, you could connect it to a digital input on the FPGA (probably R series only) and read it fast enough. You could use that signal to turn an analog output on and off at the right times. It wouldn't exactly be a peak hold, but it would be pretty close.
Hopefully this gets you closer to an answer to your question.
Bruce
Bruce Ammons
Ammons Engineering
