I'm need to count pulses having 2V amplitude, 15ns width (device spec sheet, pg2). My DAQ board is similar to NI-6356. The NI 6356 spec sheet doesn't say what kind of signals it counts but I assume it's TTL. The 2V pulse amplitude I need to count is below TTL signal level I believe. Is it possible to count these pulses with the 6356? If not, what do I need?
You can use anolog edge trigger to detect voltage level above 2V. However, I'm not sure if a sampling rate of 1.25Ms/s is fast enough to count the pulse.
The first problem is the voltage level (2V). I believe it's too low for counting pulses of this amplitude with the specified NI board, which requires TTL level pulses I think. I've seen references to a device/circuit called a level shifter for adjusting signal levels, but I've never used one and I don't know where to get it. I must be the first person to ever need to count non-TTL pulses. Strangely, the manufacturer rep for the device I mentioned in my original message can't tell me what I need to count the pulses either.
I've seen references to a device/circuit called a level shifter for adjusting signal levels, but I've never used one and I don't know where to get it.