Hi, >There's a subtle difference between 3rd phase detectors in the 74HC4046A >(Philips/NXP, ON, TI) and the 74HC4046 (Fairchild, NS) >The 3rd Phase detector in the 74HC4046A works as the designer intended >in the GPSDO circuit, the 3rd phase detector in the 74HC4046 does not.
>The 74HC4046 uses an RS flipflop for the 3rd phase detector and requires >narrow pulses on the R and S inputs. >The 74HC4046A uses extra internal gates to ensure that only narrow >pulses are seen by the RS flipflop in the 3rd phase detector. >Bruce You are perfectly correct. I hadn't noticed that there was a 74HC4046A fitted to the board in the article but just a plain 74HC4046 shown in the parts list. However, it is something to watch out for as this will be a popular project among those, like myself, who do not need to slice time quite so finely. Cheers - Joe G3LLV _______________________________________________ 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.
