HI

> On Jul 20, 2016, at 7:51 PM, Mark Sims <[email protected]> wrote:
> 
> I added the ability of Lady Heather to calculate the time offset of the 
> timing message from "wall clock" time.  It calculates the difference between  
> the system clock time to the time that the (end of) the timing message 
> arrived.   The result is only as good as your system clock, so the system 
> clock really needs to be synced to something like NTP (otherwise it does a 
> decent job of showing how much your system clock is drifting).  Heather can 
> plot the results and calculate xDEVs on both the message jitter and the 
> message offset time in real time.
> 
> On another note,  I did some jitter measurements on  Jupiter-T and Jupiter-T 
> Pico receivers.    I can't imagine how they do it, but those things are 
> insanely good.   Running at 9600 baud,  their message jitter into a hardware 
> serial port is less than a millisecond peak-peak!  Somebody paid a LOT of 
> attention to getting the message timing consistent…

Just pre-load it all into a big shift register and let the PPS output gate the 
clock to the beast.  There’s not a lot of doubt about what the label on the 
next second going out will be :)

Bob

> 
> 
>                                         
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