[time-nuts] rapid startup GPSDO

jimlux jimlux at earthlink.net
Wed Jul 14 16:13:04 UTC 2010


Luis Cupido wrote:
> Jim,
> 
> The implementation I've done on "reflock II"
> (on a MAXII CPLD form Altera
> http://www.qsl.net/ct1dmk/reflock.html )
> Had fast aqs time in mind(*).
> It captures in few 1pps pulses
> and could stabilize to about 1% of dac range
> in quite less then 60s.
> 
> How slower you need it to be in addition to the
> above timings depends on how much you want to average
> the 1pps. Having it fast it would obviously
> track the 1pps jitter.
> 
> 'how good you need' -> 'how slow it has to be'
> 
> These timings are off course after your GPS starts
> producing good enough 1pps pulses.
> 
> Luis Cupido.
> CT1DMK.
> 
> P.S. Super cheap approach is the reflockI
> (on a $5 CPLD) for which I made also a 1pps code.
> (but a few less specs and addons than II)
> 
> (*) uW Radio ham application where you arrive on the top
> of the hill and switch all equipment on and can be making
> contacts minutes after having better than 1e-8(1e-9).
> 
>

that's precisely the sort of application I'm looking at..

Wheels stopped to on-the-air in <20 minutes.



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