[time-nuts] GPSDO Alternatives

paul swed paulswedb at gmail.com
Thu Dec 6 18:16:59 UTC 2012


Boy do I have to agree. uProcs by the dozens and with all kinds of counters
onboard.
I think it was Bob who said none of thats the challenge.
It is the phase comparison method and a stable D/A converter and reference.
>From what I have seen and I could be dead wrong here the on board uprocs
have D/As but the quality is simply OK.
The other comment is that whoever writes the software gets to choose the
software and everything else. Its actually not really democratic at all.
Cause we will all use it if its reasonably good. ;-)
If I do it it will be basic! Though it will run at very high speeds. Now
someone should be jumping in with Forth real soon now.
Last tidbit the Rasberry is a pretty interesting widget and there had been
a thread about a time server. Was looking forward to the results. Nothing
ever happened.
Regards
Paul
WB8TSL

On Thu, Dec 6, 2012 at 1:00 PM, Bob Camp <lists at rtty.us> wrote:

> Hi
>
> It's a rare microcontroller these days that does *not* come with a free
> tool
> chain. Same goes for the debugger. Most MCU lines have family members with
> similarly low (or lower) prices and good availability. They pretty much all
> either work with a crystal two caps and a resistor. Most will run fine with
> none of the above on the internal clock.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Dale J. Robertson
> Sent: Thursday, December 06, 2012 12:45 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> 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.
> Dale
>
> -----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.
>
> Keenan
> VE7XEN
>
> 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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