Normand Martel wrote: > I've made a such pulse stretcher to render the 1ms > pulse from a CMC Superstar and the 10µS pulse from a > Trimble Lassen SK8 visible via an L.E.D. by using a > simple 555 timer configured in a monostable fashion. > > Sure it is not nanosecond precise and i'm not sure AT > ALL it will react to a 20ns pulse, but for a visual > monitoring, it is perfect (pulse stretched to about > 30ms).
Hi Normand -- I don't know of anyone who actually *has* to deal with a 20ns pulse, but it was interesting to see what the chip could do. I actually tested down to 8ns and it worked there, but I like to be a bit conservative when quoting performance. The main raison d'etre for the FatPPS is to deal with the typically 20us pulse width that comes from HP clocks. That's just a bit too short to reliably trigger a serial port. I also wanted to be able to easily turn a negative-going RS-232 pulse (which is what comes out of the Z3801A after the "standard" RS-232 modification) into a positive going pulse to feed the high-resolution Soekris net4501 time server. John _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
