[time-nuts] Odd-order multiplication of CMOS-output OCXO

[Gerhard Hoffmann]

Am 20.01.20 um 22:57 schrieb Attila Kinali:
> On Mon, 20 Jan 2020 12:50:09 -0800
> Mark Haun <mark at hau.nz> wrote:
>
>> True enough, but remember that my motivation for using the OCXO in the
>> first place was to combine the required phase-noise spec with
>> OCXO-class frequency stability (this is for narrowband coherent
>> modulation schemes on the shortwave bands where short-term stability of
>> ~ 10^-10 is nice to have).  The alternative is what Attila said,
>> VCXO phase locked to an OCXO.  The advantage of doing it this way is
>> that I [potentially] reduce complexity, board space, and power.
> For an SDR application, the ABLNO allone would be the best option, IMHO.
> It's low power and low noise. Even for narrowband SW applications.
> If you look at the data, you see that the cross-over between the
> ABLNO is lower noise to the OCXO is lower noise is around 100Hz.
> Unless you are operating at much lower than 100baud, the ABLNO
> is going to be enough. If you are using something like AFSK31/PSK31
> it's probably borderline which one is better and I would go with
> the ABLNO only for simpler construction and easier sourcing.
>
> If you are thinking about trpoposcatter, EME or similar things
> with really low baud rates, then I would go for the VCXO+PLL
> approach for one simple reason: Flexibility. With a PLL you
> have a choice what kind of reference you want to use.
For a back burner project, motorcycle based portable 432 MHz EME,
(i.e. collecting squares with a friend of mine who has a _huge_ antenna),
I decided to use one of these

< https://www.digikey.de/de/product-highlight/e/ecs/ecoc-2522-smd-ocxo   >

and call it a day.

432 - (4*100) = 32 MHz = somewhere in the middle of the Red Pitaya passband.
And the Red Pitaya could also run on the 100 MHz. There happen to exist nice
SAW-Filters for both 400 and 432 MHz. No tuning.

There is no Baud rate on EME, just a 600 Hz side tone. :-)     Or WSJE.

regards, Gerhard, DK4XP