Another way to achieve divide-by-N is with a non-retriggerable one-shot, adjusted to the appropriate time value. Back in the 40's/50's, the common tube circuit was called a Phantastron (really, look it up!). Phantastron dividers were used in several of the early HP counters (i.e. HP524B), because you could achieve (for example) a decade divider with a single tube, whereas a 'binary' solution requires 4 tubes (like in the HP AC-4A decades).
If a 50% duty cycle is needed, then do a divide by N/2 with a Phantastron, then a single flip-flop gives you 'N' with a 50% duty. Note that the Phantastron type divider only works if the input freq is known and fixed, because the one-shot delay has to be adjusted to a specific value. Pete On Thu, Jul 2, 2020 at 2:29 PM Gary Woods <garygar...@earthlink.net> wrote: > On Thu, 2 Jul 2020 19:23:03 +0200, you wrote: > > >Makes me think one could use the input signal edge to synchronize a > 2N6027 based programmable unijunction oscillator, thus effecting a divide > by 5. Unlikely the 6027 would be fast enough for 50 MHz, but maybe a 2 > transistor equivalent using RF transistors? Output would be nowhere near > the 40%-60% range, though. Might just have to build one for fun. > > And _that_ makes me think of an early Navy airborne Loran set that > used step counters to make the time base. Adjustments were through > holes in the side of the case, because some poor soul would have to > tweak them now and again. > -- > Gary Woods O- K2AHC Public keys at home.earthlink.net/~garygarlic, or > get 0x1D64A93D via keyserver > fingerprint = E2 6F 50 93 7B C7 F3 CA 1F 8B 3C C0 B0 28 68 > > -- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.