[time-nuts] Z3805 initial behaviour after power up

Magnus Danielson magnus at rubidium.dyndns.org
Wed Jun 17 17:53:32 EDT 2009


David Forbes skrev:
> Magnus Danielson wrote:
>>
>> None of these approaches is rocket science to design anymore. 
>> HP/Agilent surely could at the time of Z3801A and followers.
> 
> Yet the problem of an oscillator having a high drift rate after 
> long-term storage is not one that a development team is likely to be 
> thinking about.
> 
> Nor is it a problem that can be easily examined, since it requires a 
> bunch of old units lying around the development lab. Old units don't 
> exist when the product is new, and even if they had traveled back in 
> time to buy and age a few units, after sufficient testing they would 
> stop drifting and therefore be useless for the test.
> 
> Nevertheless, 25 years later we expect the whiz-bang engineers at HP to 
> have thought of the problem and solved it.

Starting any oscillator from cold is pretty upsetting and takes time to 
drift in. But sure, it is kind of not so probable that they would 
encounter it.

But still, crystal oscillators is individuals and there are other forms 
of abuse (such as chock) that can occur in an oscillators life... so you 
would expect that some anticipation of a "less ideal case" might have 
passed their minds. Ah well, maybe that is me... I hate seeing returns 
from the field only due to fairly easy mistakes in the design. Not that 
it doesn't happens, but it's a learning process to improve on design margin.

Cheers,
Magnus




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