NI PCI-6010 + Digital Input + MATLAB DAQ Toolbox

[Zhiv]

I've a circuit that starts outputting digital pulses at 60 or 120 Hz once something is displayed on the PC monitor. The idea is to have a very precise estimate of the time at which something was displayed on the monitor. My experiments are coded in MATLAB and so I will need some way to get a timestamp of the signal that starts arriving at the onset of the display. The timestamp that I will get when I use the DAQ functions will be with respect to the NI card's clock, right? I've been using GetSecs right before the command to display the stimulus to get an estimate of the stimulus onset time. Now with this digital signal, I want to look at the difference between what GetSecs returns and the time at which the signal exactly arrived. Does anyone think it's doable? Cheers, Zhivago...

[Zhiv]

Another question is what mode will be appropriate to acquire the digital signal, foreground/background?  Or, will it be easier to deal with if the signal is acquired as an analog input?

Thanks,

Zhivago...