[time-nuts] Thunderbolt? (re simple gpsdo.)
mspencer12345 at yahoo.ca
Fri Dec 30 14:13:41 EST 2011
On a related note is anyone aware of PC controlled (Ie. RS232 or maybe GPIB ?) DAC's that would be suitable for this type of application ?
I've also contemplated simply using the DAC of a TBolt but it would seem to be waste of a Tbolt. I'm thinking along the lines of something that might acquired used on an auction site.
--- On Fri, 12/30/11, Hal Murray <hmurray at megapathdsl.net> wrote:
> From: Hal Murray <hmurray at megapathdsl.net>
> Subject: Re: [time-nuts] Thunderbolt? (re simple gpsdo.)
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> Received: Friday, December 30, 2011, 1:16 PM
> > "What is the simplest design for a GPSDO that uses
> only the PPS signal from
> > a modern GPS?"
> Some sort of oscillator with a voltage control.
> CPU with a timer/counter that can capture the PPS.
> Drive the CPU from the osc so you can count cycles between
> PPS pulses. Use
> the DAC to adjust the frequency. Build a low pass
> filter in software.
> The DAC may be the tricky part. You would like lots
> of bits, but it also has
> to be stable.
> With a given DAC, you can get finer control by trading off
> These are my opinions, not necessarily my employer's.
> I hate spam.
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