Hi, A fellow amateur and I have just put together the GPS-based frequency reference published in the "Every day Practical Electronics" issue of April/May 2009 and are both experiencing the same problem. The type-3 phase comparator of the 74HC4046 has both 1-pps and 50kHz DC-coupled inputs designed to produce an error pulse due to the difference between their leading edges. However, the longer pulse dominates the output because it holds the latch in thrall despite the 50kHz pulse trying to grab a little of the action.
My question is then, are there variants of the 74HC4046 that have a type-3 detector which is edge-drive only? Natch, I can AC-couple and clamp them but I just wondered. I know that in the past that there have been differing versions of the old CD4046 and now, of course, there are also the '7046 and '9046 types around. Cheers - Joe G3LLV _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.