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A look at my Symmetricom GPSDO / 10MHz reference (OCXO + Furuno receiver)

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Macbeth:
@jackenhack. Thanks, yes the pulse width is very narrow. Thanks for that, I probably would have wasted hours debugging it  :palm:

jackenhack:

--- Quote from: Macbeth on December 22, 2015, 06:30:27 AM [email protected] Thanks, yes the pulse width is very narrow. Thanks for that, I probably would have wasted hours debugging it  :palm:

--- End quote ---

Getting the 74HC123 tomorrow, so I'll keep you posted on if it works.

Added a rudimentary display to the NTP server so I could get the time, and also get some status so I know when the network goes down and it switches to GPS/PPS only. It's no Nixie clock but it's something.   :)

https://dl.dropboxusercontent.com/u/261736/Images/ntp-server-display.mov

Macbeth:
But are you taking into account the 1/4 second delay by triggering on the falling edge?

I quite like my earlier alluded to PTIME:TCODE? serial query, and then I would use an interrupt rather than polling to snatch that 1PPS just within that 10us period. Also, don't forget you have to program in the antenna delay too - use GPS:REF:ADELAY <seconds>, e.g. 25E-9 for 25ns (5 meters cable)  - ok that would help with the 10MHz more so ;)

But maybe the TOD output takes account of a lot of this. Like it should take account of baud rate, etc. No exact documentation to go on, so ???

jackenhack:

--- Quote from: Macbeth on December 22, 2015, 10:09:09 AM ---But are you taking into account the 1/4 second delay by triggering on the falling edge?

I quite like my earlier alluded to PTIME:TCODE? serial query, and then I would use an interrupt rather than polling to snatch that 1PPS just within that 10us period. Also, don't forget you have to program in the antenna delay too - use GPS:REF:ADELAY <seconds>, e.g. 25E-9 for 25ns (5 meters cable)  - ok that would help with the 10MHz more so ;)

But maybe the TOD output takes account of a lot of this. Like it should take account of baud rate, etc. No exact documentation to go on, so ???

--- End quote ---

There shouldn't be a delay. The circuit resets and waits for the next rising edge. You can adjust the time with R1 and C1. With these values, you should get about 250ms.

Yup, have measured the length of my cable, even checking the speed the HUBER+SUHNER cable propagates signals and added the delay. :-)

Deathwish:
does anyone have the pin outs for that symmetricom units ribbon cable

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