[time-nuts] GPS Referenced Programmable Oscillator...

[Tim Shoppa]

Given the extreme output range (450Hz to 800MHz) it must have a DDS with no
filtering at each output, right?

I don't think the mystery TCXO runs at 1.6GHz, but some GPS-TCXO inside is
instead multiplied way way up.

Tim N3QE

On Mon, Oct 19, 2015 at 8:20 AM, Attila Kinali <attila at kinali.ch> wrote:

> On Sun, 18 Oct 2015 17:56:36 -0700
> "Burt I. Weiner" <biwa at att.net> wrote:
>
> > I just ran across this and wonder what you think.
> >
> >
> http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html
> >
> > Seems like it could be set up as a reference to replace crystals in
> > some Ham rigs such as a repeater transmitter and receiver.
>
>
> I've seen this being mentioned a couple of times in the past weeks.
> The phase noise looks ok'ish. Not great, but not too bad either.
> Though I doubt that he'll be much below the noise floor of his instrument.
> 140dBc is about what you get with most VCXO/TCXOs. To be better you
> need to know what you are doing and/or use a good oscillator, which
> becomes expensive (a good, low noise VCXO costs already 100USD
> in small volumes unless you build it with discrete components,
> which then takes considerable knowledge).
>
> An ADEV plot and any kind of schematics are missing completely.
> Also without any reference, I would distrust the way how the
> system is build. There are ways how people trying to do the right
> thing will mess up in subtle ways. (e.g. like using an FLL instead
> of a true PLL, as is the case for the BG7TBL GPSDO)
>
> For 200EUR, it's also on the expensive side, if you compare it with
> what you can get on ebay. Of course, there is the difference between
> a used device and a new device.
>
> On a personal note, the product description reads too much like
> "hey, the guy who designed this is really really great!"
> I am not sure what I should make of that, but I don't think that's
> a positive attribute.
>
> In summary, I'd probably wait for a time-nuts to get his hands on this
> litte gadget and do some serious measurements before I'd trust it.
>
>                         Attila Kinali
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
>                  -- Miss Matheson, The Diamond Age, Neil Stephenson
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