On Wed, Mar 5, 2014 at 5:43 PM, Didier Juges <shali...@gmail.com> wrote: > Tom and Bob, > It is not obvious to me that it is "easier" to simply apply a correction in > nS increments with a range as wide as 100nS. How is this done? Using > switched delay lines or delay gates?
Here is my plan for processing saw tooth data. If it's not going to work I'd rather hear about it now then a month from now after I've put in some effort. This is going into Lars' Arduino based GPSDO. Every second I read the voltage on a TIC capacitor. This tells by the phase in nanoseconds between the PPS and the OCXO. Then I add whatever the current GPS sawtooth value is to whatever my TIC said. I compare this to a set point. This is the phase error. The OCXO is adjusted based on a filtered version of this error. So in short, I don't correct even try to delay the pulse. I don't see any need to do that. I measure the pulse and get a number in nanoseconds. then I use sawtooth to correct the number. It seems way-hard and with no purpose to correct the pulse and then measure it. Better to correct the measurement. I think it is more accurate too a delay could never be perfect. The controller has LOT of spare capacity so I don't see way I can't add one of more TIC channels and a few more DACs I should be able to discipline an OCXO and my Rb oscillator from the same GPS PPS input. The 74HC360 is only 1/2 used an Arduino has enough spare pins. Any one more 74HC4046 and some passive parts would be required to build a dual channel GPSDO. It will be interesting to look at andompare the 10MHz outputs of two oscillators that are being disciplined by the same controller and GPS receiver. -- Chris Albertson Redondo Beach, California _______________________________________________ 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.
