[time-nuts] Adjusting HP 5065A frequency

[Magnus Danielson]

Warren,

On 10/23/2012 12:45 AM, WarrenS wrote:
> Tom said:
>
>> In general, when you discipline a OCXO you get that characteristic ADEV
>> "hump".
>> At some point there is a cross-over and you know/assume that at that
>> point
>> each must be contributing 1/sqrt(2) of the noise.
>
> Although putting the Hump at the cross over point is typically a good
> compromise, there are other choices which give different trade-offs.
>
> Attached is a excell plot showing the effect of different PID tunings
> on the Hump's size and location.
> This spread sheet (originally is from Wenzel's site) was for plotting the
> effect of the RC H/W values for a PLL when used as a clean up Osc,
> but can be used for setting the PID values of a disciplined GPS
> such as a Tbolt with a few changes and using different data.

As expected, the hömp (sorry for sudden Inspector Clouseau) depends 
greatly on the damping factor. Lowest hump you get from the high 
damping-factor (40) located at the cross-over point of the two curves.
The remaining hump is what you need to live with as the noises is 
spliced together by the high-pass/low-pass action of the PLL.

Good illustration. I haven't seen it before, but it is expected.

Cheers,
Magnus