[time-nuts] What sort of oscillator is this?

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 28 Sep 2014 03:11, "Alexander Pummer" <alexpcs at ieee.org> wrote:
>
> that is most likelly a TXCO, what is in the user's manual about warm up
time?

Two people responded - one says a OCXO and the other an TCXO!!

The warmup time is I think an hour,  but clearly that is not the time for
an oven to warm up.

If it was a frequency counter then I think the warmup time would be just
that of the oscillator,  as really I can't see much other than the
oscillator needing to be stable. But on a VNA one needs the temperature of
cables to be stable,  as expansion of cables is likely to cause phase
instability. So the time for the cables lengths to stabilise is probably
much longer than it would take an oven to stabilise.

> if they have a special precise reference -- like for spectrum analyzer or
frequency counter that would have at least one magnitude better stability

I find it odd that an instrument that probably cost $50,000 when new did
not have a TCXO as standard,  and perhaps an oven as an option.

But I think HP did this sort of thing a lot. Something that would have cost
very little to add, became an expensive option. In some cases these
expensive options are nothing more than enabling a bit of software,
although the R&D cost of the software is probably a lot more than the
hardware cost of adding a better oscillator.

Dave.