Bruce, I think there may still be a problem if you only have one counter latch and a tag to indicate which input's data is in the latch, aside from metastability issues. If two of the signals you want to compare are very close in timing, there may not be enough time for the processing logic to collect the data from the first pulse before the second one comes along.
As Poul pointed out, if you compare two GPSDOs that are a few nS apart (or less), that puts a new strain on the logic collecting data. If each input has its own counter latch and you are measuring PPS signals, you have a whole second to process the data. I guess there could be an issue with multiple counter latches that propagation time within the device may not be the same for all inputs, and calibration (and possibly temperature compensation of that delay spread) might become necessary? Didier > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bruce Griffiths > Sent: Saturday, December 01, 2007 6:40 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Of rubidium life and piggy-bank anemia.... > > Poul > > As I suspected we had our wires crossed, I was talking about > the counter value latches not the synchroniser latches /D-flipflops. > > Bruce _______________________________________________ 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.
