[time-nuts] HP-10811AB-OCXO interface questions

[Bob kb8tq]

Hi

> On Sep 2, 2020, at 1:24 AM, Manfred Bartz <vk3aes at gmail.com> wrote:
> 
> Hi all,
> 
> I bought 2 x 10811 OCXOs for a 10MHz GPSDO project I am working on.
> The OCXOs came with an interface board HP 05328-20027, see attached
> pictures.
> 
> Questions:
> 1. Is it worth keeping the interface board?

They make an adequate “burn in” board. There isn’t a lot of use for them 
otherwise. 


>    a. If yes, does anyone have the schematic and the data on the ICs?

You can trace it out. It’s an ECL doubler or something like that.

>    b. What is that TO220 device?  

It’s the 12V regulator to drive the oscillator. The 10811 uses > 20V 
for the oven and ~ 12V for the oscillator

> and
>    c. why is it mounted on a standoff on the back of the PCB?

It shipped that way to keep it safe. It mounts on the chassis of the 
instrument this board plugged into.

> 2. Any advice/caution on matching the OCXO output impedance?

10811 is designed to run into a 50 ohm or 1K ohm load. Most run them
into a 50 ohm load. 

> 3. Any recommendation for a (>= 4-ch) distribution amplifier?

Depends a lot on what you are after. I did a post of some op-amp 
data back a few months. None of them would “preserve” the far removed
phase noise of the 10811.

> 4. Any advice on a low jitter comparator for further digital processing,
> e.g. for a 1pps signal?

The previous post about the LTC part is one way to go. A simple biased
gate (like that used on the interface board) is another way. A lot depends
on just how low “low jitter” needs to be. 

Bob

> 
> Thanks and 73
> -- 
> Manfred  VK3AES
> <HP-10811AB-OCXO-IMG_20200805_201555.jpg><HP-10811AB-OCXO-IMG_20200805_201615.jpg>_______________________________________________
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