Hi Lee, We all had a first time posting on this list and survived it. No problem.
You need to know more about phase locked loops. In this case, you need a voltage controlled crystal oscillator that a simple binary divider can take down to 1 PPS. That 1 PPS is compared to the GPS 1 PPS with a simple flip-flop, which produces a pulse width that can be filtered to be the control voltage for your VCXO. The resulting feedback loop causes your VCXO to track GPS. Now then, this is a great oversimplification of the process for getting very low timing errors. However, human time constants for observation of a clock do not require very low timing errors. Very few people would notice a 50 millisecond error. To get a useful answer from this group, you need to specify the accuracy required. If you want picosecond errors, you are into big bucks. Nanosecond errors are expensive but can be found on eBay. Microsecond errors still need a good GPS receiver (not cheap). Millisecond errors are not normally the subject of this group, although there has been a thread on receivers barely capable of that. Lurk and learn, grasshopper. The cost is low until you decide on the level of accuracy you wish to reach. Best regards, Bill Hawkins P.S. I was afflicted with the desire for accuracy down to the Caesium standard level. Hydrogen masers remained beyond my means. Now I live in an apartment in an old folks community, which required severe downsizing. The return on investment was negative. The older I get, the less I require precision time. YMMV. -----Original Message----- From: time-nuts [mailto:[email protected]] On Behalf Of Lee - N2LEE via time-nuts Sent: Tuesday, October 18, 2016 9:03 PM To: [email protected] Subject: [time-nuts] 1PPS to 32.768 khz First let me say this is first time I have posted to the group so go easy on me. :) Secondly I want everyone to know that you guys make me feel so NORMAL for wanting to use and understand accurate timing devices. I thought there was something seriously wrong with me now I know there are others affected with the same disease. hehe Now my questions. 1. Does anyone know of a device that will take a 1PPS GPS timing signal and generate a 32.768 kHz sine wave output ? I have big digital clock that uses an 8 bit micro processor and an external 32.768 crystal. Obviously the external crystal is awful for accuracy. I have searched every where using as many search terms as I can think of and can't believe there is not a device that performs this function. I have found a couple of Epson RTC chips that might come close that 1pps but I don't think that corrects the 32khz just the clock time. 2. 10 Mhz Freq Standard I am not in the same league as the majority of the list members and just starting to dabble in GPSDO stuff. I have tried to find a thunderbolt as a starting device but it appears those are either dried up or people want too much money. I wanted to get the opinion of anyone who has tried the Leo Bodnar GPSDO ? For the money it appears to offer a beginner a lot of features. Thanks and reading the daily digest of what you guys are working on. I have a feeling if I am not careful you guys could cost me a lot of money. hehe Lee _______________________________________________ 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.
