[time-nuts] Frequency referenced temperature regulator

[jimlux]

Oz-in-DFW wrote:
> 
> On 11/8/2010 9:04 AM, Poul-Henning Kamp wrote:
>> But since I happen to have access to much more stable frequencies
>> than voltages, I thought of a different way:
>>
>> 1. Mount a X-tal-osc with really lousy tempco inside the enclosure.
>

>> Has anybody tried that ?
> It's been my experience that oscillators with really lousy temperature
> performance have really lousy repeatability as well.   I'm never delved
> into why this is true, but I suspect it's a number of things and not
> limited to the quartz resonator.
> 

Depends on *why* it's a lousy temp performance.. is it that the crystal 
has poor performance OR that the crystal is low Q (e.g. in a TCXO) and 
the frequency is affected by the other component variations in the 
circuit.  There are some circuits where the bias changes with 
temperature, and therefore, the power (and hence heating) through the 
crystal changes, for instance.