[time-nuts] Averaging effects

Magnus Danielson magnus at rubidium.dyndns.org
Tue Dec 28 00:16:43 UTC 2010


On 12/27/2010 11:49 PM, Bruce Griffiths wrote:
> Then add an isolation amplifier with at least 40dB reverse isolation
> between each OCXO and the measurement system and repeat.
> If the shielding is adequate (and coupling via power supplies or other
> stray paths is sufficiently small) any injection locking effects should
> be significantly reduced.

Now, I did mention my setup as somewhat of a hack. Lack of separate 
power supplies... (both BVAs hang on the same crocodile clips from 
obviously the same PSU). I'd be happy to use isolation amplifiers if I 
had any, which I lack just as much as I lack amplifiers. As for physical 
separation... there is probably a full cm of distance between the 
oscillators as they sit there in the mess on the table. I could measure 
the distance if needed.

Just so you know what you are dealing with here.

Anyways, the good things is that I've got the lab start being used. 
Things will be fixed as I go along. Cooking up a simple isolation 
amplifier should probably allow itself to be done.

Oh, and it seems like the PSU in my HP5372A just went bust. Darn. Guess 
I will have to look at that one. Have another counter with a similar 
problem.

So I think there are a few things to do. Besides a bunch of PICTIC II 
boards to solder.

Cheers,
Magnus



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