01-31-2016 05:02 PM
Google says the "on" threshold for TTL pulses is 2.0 volts (Vih). But I need to measure frequency of pulses that don't all reach 2.0 volts. Is that possible? My (limited) understanding is that the counter/timer input to my DAQ device (USB-6221) requires TTL signals. Does that mean I can't count anything but TTL pulses? Or is there a way to adjust the threshold?
01-31-2016 07:25 PM
01-31-2016 08:35 PM
Analog acquisition would be much slower, right? That is, the frequencies that could be measured would be lower because of the processing (comparing numbers) and lower sample rate, no? More error prone as well, I imagine.
01-31-2016 08:43 PM
02-01-2016 12:31 AM
Where can I get a (comparator/shifting) circuit? Can they keep up, ie are they as fast as the counter input?
Will this do? I don't see anything in the spec sheet that says what level the input signal has to be in order to create TTL output.
I'm not an electronics expert, just somewhat knowlegeable. I understand the concept, just not sure I can make it happen.
thanks!
02-01-2016 07:19 AM