[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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