[time-nuts] Linear voltage regulator hints...

Bob Camp kb8tq at n1k.org
Sat Dec 13 08:53:01 EST 2014

> On Dec 12, 2014, at 10:53 PM, dan at irtelemetrics.com wrote:
>    Hi Bob,
>> or 1x10^-8 per volt. If it’s a 10 MHz OCXO. 
>> That would be 1x10^-14 per uV
>> 4.7 x 10^-13 for 47 uV
> Good, so I'm not out to lunch here. ;)  Thanks for verifying those 
> numbers for me!
>> What makes you believe that the OCXO’s temperature performance it 
> not the issue?
> Because I can blow a hair dryer on it, and make very warm - almost 
> hot to the touch and not see the phase or DAC change. Yet 2 degree 
> thermal cycles in the room show up in the DAC and phase. I'm pretty 
> sure it's not the OCXO, but if you know anything that would suggest 
> otherwise, please do share. 

I’ve been through the math multiple times. I’ve compared your OCXO’s to the data on best parts on the market. 

Let’s see:

You claim you are heating up the OCXO by 30 C or so. The frequency must be below 4x10^-13 to be below your other effect. If so, your OCXO would do < 3x10^-12 over -40 to +85. That is not possible with an OCXO. 

What is the part number on the OCXO you are using? 

Who made the OCXO?

Is there a spec sheet on the OCXO or a similar part from the same outfit?

Dig in a bit and you will have a very hard time finding parts that are as good as the numbers I’ve been using.


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