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

[Mark Haun]

On Mon, 20 Jan 2020 14:44:01 -0500
Bob kb8tq <kb8tq at n1k.org> wrote:
> > On Jan 20, 2020, at 2:38 PM, jimlux <jimlux at earthlink.net> wrote:
> > On 1/20/20 10:01 AM, Mark Haun wrote:
> >> A fair question... in fact I was initially planning to use the
> >> ABLNO + a PLL.  The OCXOs I found, however, are CTS VFOV405's with
> >> phase noise claimed to be just as good as the ABLNO or CVHD VCXOs:
> >> https://www.ctscorp.com/wp-content/uploads/VFOV405.pdf
> >> They are reasonably low power, small[-ish], and have adequate
> >> stability for my needs.  You can see why it is tempting to make
> >> the multiplier scheme work, as it should save on both power and
> >> board area. (The target application is a battery-powered SDR.)  So
> >> far there don't seem to be any show-stopper issues with the plan,
> >> except that I am going to have to put together a phase-noise
> >> measurement system, or find a friend with one.  
> > 
> > Have you checked delivery times? - Just because it's listed in the
> > catalog does not mean you can get it in the next few weeks or
> > months. If the online sources (Digikey, mouser, Newark, etc.) have
> > them in stock, then you're good to go, but otherwise you could be
> > looking at 6 months or more.  
> 
> …. and maybe nasty stuff like minimum order quantities in the range
> of 10 or 20 pieces ( or prices below that which work out to the same
> thing). 

No, these are from Ebay.  A guy in Texas has been salvaging them from
(I assume) telecom equipment:
https://www.ebay.com/itm/CTS-16-384MHz-OCXO-3-3V-Oven-Controlled-VFControl-50ppb-120mW-VFOV405-TCEDH/113877523761?hash=item1a83a11d31:g:3JQAAOSwxN5WXv4q

Obviously all of the caveats about used OCXOs apply, but at least they
weren't melted off of scrap PCBs by kids in China.  This is a hobby
project so I don't plan to build more than half a dozen of my
design-in-progress.  Assuming it happens at all ;)

Regards,
Mark