The programmable PIC or AVR or ... chip that will do the job are same or less than a 555 chip, and a lot more flexible. --- Graham
On Fri, Jan 15, 2016 at 11:55 AM, Adrian Godwin <[email protected]> wrote: > Why use a board full of TTL when an $1 8-pin chip will do it ? > > > On Thu, Jan 14, 2016 at 11:44 PM, Morris Odell <[email protected]> > wrote: > > > Am I missing something here? > > > > I understand the ease and fun of programming up an AVR as much as anyone > > but surely this task could be accomplished easily with a chain of fast > > synchronous TTL or CMOS dividers. A resynchronising FF could also be > added > > at the end to clean up the 1 pps if required. You wouldn't need to worry > > about the maths or OBOBs either. > > > > Admittedly you would need more PCB real estate but that shouldn't be a > big > > deal in most cases. > > > > Morris > > > > > > > >>> If anyone is interested in the equivalent functionality using an > >>> ATTiny25 (for instance, if you’re already heavily invested in AVR > instead > >>> of PIC, like I am), ping me. I’ve privately written code to solve > almost > >>> the same problem and it could easily be adapted into doing the same > job. > >>> > >>> > > > >>>>> Is there an easy circuit to build that can consistently deliver a 1 > >>>>> PPS from a 10MHz source with excellent resolution and > repeatability? My > >>>>> first application is to test different 10MHz oscillators without a > TIC > >>>>> always attached and then compare the PPS output change over time > against a > >>>>> master GPSDO PPS with an HP53132A. > >>>>> > >>>>> The circuit used for PPS generation would have to deliver consistent > >>>>> PPS output with preferably not more than 100ps noise or jitter, > assuming a > >>>>> perfect source. I'm totally guessing that for this resolution, the > PPS > >>>>> would have to be generated and accurate to within 0.001Hz every > second. If > >>>>> this is too difficult, maybe the integration time can be increased to > >>>>> generate one pulse every 10second or every 100,000,000.00 cycles? > >>>>> > >>>> > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
