Brooke Clarke wrote: > Hi: > > I came across a 1946 patent for a vacuum tube based counter circuit that > will divide 60 Hz down to 1 Hz. It's interesting in that there's a > discussion about the advantage of using binary instead of base 10 and > also about using feedback to change the scale of the counter from 64 to > 60 (or 50). See:
Brooke, This appears to predate the old Berkeley and HP decade counter modules by quite some years, although it is slightly different in that it treats a single base-60 digit instead of two BCD digits. Amusingly, by the time of color television in the fifties, RCA was selling a low-cost color bar generator whose sync generator used the phantastron divider instead of this binary divider. The phantastron was also used in the HP counters for the reference clock divider; it is a two-tube divide-by-N circuit that charges a capacitor with N little pulses, then triggers and resets itself. Also amusing is the patent application date of 1942 and the granting date of 1946 - these times bracket ENIAC's protracted development and building period. However, ENIAC did not use binary counters - it used decimal up/down ring counters which were a faithful emulation of the mechanical wheel accumulators used in adding machines of the day. All in all, a nice bit of history. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
