[time-nuts] GPS: ADEV or MDEV?

[Didier Juges]

Dr Bruce Griffiths wrote:
> Said
>
> SAIDJACK at aol.com wrote:
>   
>> Hi guys,
>>  
>> Some comments:
>>  
>> * The Vref output of most OCXO's is from a Zener diode inside the can.  These 
>> typically have aging, thermal sensitivity and very poor voltage  accuracy, 
>> and there are much better monolithic high-precision, low-tempco  voltage 
>> reference available on the market now (Digikey etc). Depending on the  internal 
>> design of the OCXO, it may help the noise and stability to add an  external 100uF 
>> or larger tantalum cap to the Vref pin, since it's voltage is  likely used as 
>> the power supply for the Oscillator etc.
>>   
>>     
> If you want the lowest tempco and drift available try using an LTZ1000 
> (used in HP 8 1/2 digit DVMs).
>   
In those cases where a thermally stabilized reference is undesirable 
(power consumption, power dissipation, thermal stabilization time at 
power up), see Thaler www.thaler.com
They have the best (as far as I know) thermally compensated references 
and the best initial accuracy.

Didier KO4BB