[time-nuts] rapid startup GPSDO

[Bob Camp]

Hi

I would guess that a fairly simple TCXO / fast lock GPS combo would get you pretty close. 

Bob


On Jul 14, 2010, at 12:13 PM, jimlux wrote:

> 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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