Trying to lock a pulse to a 1Mhz signal DAQmx

[Mark_Andrews99]

I have a 1 Mhz signal and am trying to get a pulse to occur right before the negative edge of this signal. I have both signals working but the pulse won't lock. I am using the "Create Virtual Channel" with the CO-Pulse and using high time and low time to create my pulse. Anybody know how to do this?

Thanks!

~Mark

[Kevin_Price · Accepted solution]

Not near a LV box, can only describe in text.

Configure a retriggerable single pulse.  (Do some searches for more info & examples.)

Trigger off the rising edge of the external 1 MHz signal.  Define high, low, and initial delay times to place your very short pulse just before the 1 MHz falling edge.  

If the external signal is 50% duty cycle, the falling edge occurs 500 nanosec after the rising edge.  I'd set high time to 100 nanosec with low time and initial delay at about 350-390 nanosec to leave a small margin for timing variability.   100 nanosec is the smallest interval that will be supported across the largest fraction of DAQ devices.  Many newer devices would support shorter pulse widths, but I don't know what you have or how important a shorter pulse width would be for your application.

-Kevin P