alan.ambr...@anagram.net said: > How about a 1pS resolution TIC? :) An alternative way to describe that sort of problem is How accurately can you locate an edge?
I haven't looked carefully at the Spartan 3E. You might be able to run a signal along a column through a slow path and clock the whole column at the same time. Then sort out how far it got. That "slow path" is basically a delay line with many taps. It would take some experimentation, and maybe some duplicate logic for run time calibration. > Or a >12 digit frequency counter? :) :) 12 digits is easy. Just wait long enough. So that turns into 2 games: How fast can you count? How many digits can you get in 1 second? Here is a toy that would be useful: assume you have a 10 MHz reference clock. make a design that captures something like a PPS and spits out the time-stamp on a serial port. I think Tom has a PIC that does that. The idea here is to use a faster clock so you get better resolution. How much resolution can you get with pure digital logic? (no delay lines) I'd like something like that watching the power line. You might need some sort of compression scheme or the serial port would get overloaded. 9600 baud is 1K characters per second. 60 Hz is 16 ms per cycle so you get 15 characters per cycle (plus a separator) unless there is noise on the line. 9 digits gives you ns. within the second. Every second or so you could send the high-order digits. -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.