[time-nuts] Linear voltage regulator hints...

Azelio Boriani azelio.boriani at gmail.com
Sat Dec 13 12:16:22 EST 2014

>...is the fact that the GPS is very temp sensitive...<
What have you observed, out of the GPS, with the temperature variations?

On Sat, Dec 13, 2014 at 6:08 PM,  <dan at irtelemetrics.com> wrote:
>     Hi Alex,
>  Monitoring the temperature control loop of this OXCO is even easier than
> that. Currently instaled is a HP10811. It has a very handy oven monitor pin,
> that varies voltage with what the control does to keep temperature constant.
> (Those HP guys were really thinking!) Any time the oven has to react to
> something it's visible on that pin. Albeit, most of the stuff is in the
> 100uV or under level, but it's there.
>  Currently there is a 8Ch 24bit DAQ card tied to this whole thing, and the
> card has proven to be more than stable enough to see what's going on. There
> is some correlation between the bulk supply voltage and DAC/Phase, so the
> next step is to chase that down. Just not exaxtly sure how it's getting in
> there. It's interesting what can be learned from looking at a bunch of
> data...  The really interesting thing is what's going on with the GPS
> temperature. You can see it ramp temp slowly, then drop 1/2 deg F, then ramp
> up slowly, and drop again. One would guess that it's tied to CPU load or
> similar. The only thing that bothers me about that, is the fact that the GPS
> is very temp sensitive. It may very well be the limiting factor. I have yet
> to monitor the VCC to the GPS, so there might be something more to learn...
> 73,
>  Dan
>  >
>  > just thinking; OXCO is one ovenized crystal oscillator with temperature
>  > control, better to say temperature stabilizer, thus if the outside
>  > temperature changes the control loop shall keep the internal temperature
>  > constant-- by definition,
>  > the function of the temperature control loop could be observed by the
>  > variation of the supply current of the oven. Also the reference voltage
>  > supplied from inside of the OCXO is coming from a voltage source which
>  > has stabilized temperature, therefore it is "a relative stabil reference
>  > voltage source", which could be used to compare the stability of other
>  > voltages and thus, it could be found which voltage is moving with the
>  > environment's temperature.  > 73
>  > Alex
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