Use USB 6341 to generate digital pulses from differential analog input

[carless]

My input is a series of differential analog pulses (~5kHz). The input analog pulses are very weak signals, -0.04V~0.08V.

I wanna generate a digital pulse whenever I detect an analog pulse. And then use the generated digital pulses as the trigger of all my other devices. 

I looked at the output digital pulses using an oscilloscope. It turns out the the pulses I got are very slow. Please help me figure out where the problem is.

Thanks in advance!

[Deagle]

How slow are the pulses? Since your digital output is changing via software-timing, you're limited to the response time of your computer. What specific timing requirements do you have for this application?

[carless]

The pulse frequency is 5kHz.The duty cycle of the pulse is 10%

I wanna make my digital pulses synchronized with the analogy pulses. I think I should use the analog trigger. But I don't know how to use the analog trigger.

[Deagle]

Carless,

You're right, analog triggering is how we would accomplish this. Unfortunately, the USB-6341 does not support analog triggering (see specs). Any 635X or 636X X Series would have analog triggering (e.g. USB-6351).  The 632X and 634X do not.

[carless]

Thanks for the reply!

Is there any way we can work through this using the 6341?

[Henrik_Volkers]

Why not build up a little circuit with a comparator?

20mV to 40mV @ 5kHz could be build on any breadboard with a LM393 
or use a TL714C with 10mV build in hysteresis and push pull output 

[carless]

I guess this is the best way to solve the problem. Thanks!