[time-nuts] 10811

[Bob Camp]

Hi

Most charts show the temperature coefficient going through zero around 5V and passing 2 mV/C in the vicinity of 6V. 

Bob

> On Nov 18, 2014, at 12:10 PM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
> 
> 
> 
> On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote:
>> I ground one side of the tuning diode and use the 2 to 12 V as the external
>>  OCXO for my FRK's along with increasing the time constant. I have not
>> verified it but I think removing the zener Voltage should also improve  ADEV.
>> Bert Kehren
>> 
> 
> The choice for the Zener diode came from my old boss at HP,
> who was very knowledgeable about using discrete zener diodes
> as low noise references.  According to him, this particular
> part number has very respectable noise.  This is just something
> you have to know experientially, there is no theory of zener
> noise AFAIK.  You might try measuring the noise of the 6.2V
> reference voltage directly at baseband, and then multiplying
> by the 1 Hz/volt sensitivity.  Let us know your results.
> 
> Rick Karlquist N6RK
> (Now retired from HP/Agilent/Keysight)
> 
> 
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