Hang on here. If the signal was 10 MHz for ref and RB its easy as suggested here XOR gates and such.
But the GPS is a 1 second interval and the RB is 10 Mhz. So the GPS 1 second is the reference. Thats much harder then dealing with 100 Hz or up. So the answer I have seen which seems to fit is Bobs comments earlier. That is the numbers/thinking are right and it would take a really long gate time to become more accurate. I may get a slight improvement by using the better reciever that has a tighter 1 PPS. I do see what I am betting is a jitter on the Novatel. But its not a timing receiver. Regards Paul. On Fri, Feb 10, 2012 at 7:35 PM, Chris Albertson <[email protected]>wrote: > On Fri, Feb 10, 2012 at 3:52 PM, Bob Camp <[email protected]> wrote: > > Hi > > > > I think you will need some sort of analog detector to get what you are > looking for. > > I don't think it needs to be analog. For example you can xor the two > 10MHz signals and then sample the digital xor output then deduce its > duty cycle by counting how many samples are 1 and how many are 0. > You'd expect an equal number if there is a phase lock. Might be best > to sample a-periodically at random. > > Many designs put a low pass filter on the XOR but I think random > polling allows the software to adjust the time constant and is cheaper > to implement. I think you'd have the latch the xor in a flipflop as > it would move to fast for a uP to read. > > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > 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. > _______________________________________________ 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.
