[time-nuts] GPSDO Alternatives

Dale J. Robertson dale at nap-us.com
Thu Dec 6 17:45:00 UTC 2012

Arduino is Dirt Cheap!
At it's cheapest it is just an atmel AVR, a crystal, 2 caps and a resistor 
with the arduino bootloader programmed into it. Easily obtainable from 
several sources for 5 bucks or so. All the code, toolchain etc. (the 
ecosystem as it were) is free. it's real easy to put one together on a piece 
of perfboard. If you're gonna put the phase detector, dividers etc. together 
anyway there's really no need to clutter things up with some ginormous 
commercial arduino board.

-----Original Message----- 
From: Keenan Tims
Sent: Thursday, December 06, 2012 10:38 AM
To: time-nuts at febo.com
Subject: Re: [time-nuts] GPSDO Alternatives

As a lurker, I just want to chime in and say that I for one would love
to see an open-source GPSDO implementation. There are quite a few open
hardware designs out there, but as Bob suggests, all the interesting
bits are tied up in the closed-source software they run. And most of
them are no longer maintained, meaning it's getting hard to find parts.

I've thought on designing a hardware platform to support a GPSDO as
well, but don't have the time-nut or control theory skills (or
equipment) necessary to make the software any good. My hope at the time
was that a build it and they will come approach would solve those
problems, but I haven't had time to make that gamble.

As far as uP choice, Arduino's only saving grace is the pool of existing
'developers' in the amateur community for it - but that's perhaps a big
deal here. It's expensive, doesn't include debug hardware, and is slow
with not many peripherals. I'd second the STM32 ARM Cortex platform, or
suggest MSP430 if you want to stay cheap and slow.


On 2012-12-06 1:28 AM, Chris Albertson wrote:
> On Wed, Dec 5, 2012 at 2:50 PM, <SAIDJACK at aol.com> wrote:
>> If there is one thing I learned, it is that one is never finished 
>> improving
>>  the software. That is why we are time-nuts I guess.
> This is the reason I suggested using the Arduino.  It is so easy to 
> program
> that MANY people will be able to contribute.  That is my goal, a GPSDO 
> that
> can be a "living project" that is not dependent on one or a few experts.
> I'd like to see a budget of well under $100, again so that more people can
> contribute and experiment.
> A design that can evolve will have just about any performance people want.
>  So don't worry about if it is 1E-12 or 1E-15.  Just make it transparent
> and easy to understand and modify.

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