[time-nuts] Fw: OCXO PLL gains?

[Anders Wallin]

I played around with this today, recording 5 minute runs: freerunning, P/10
gain, P gain, 10x P gain (where P is some unknown value...)
I then added either a 1M/100n or 500k/100n integrator which really only
shows in the TDEV-plot, not in the PN-plot.
https://photos.app.goo.gl/V9xL5MkVsL6RLRXJ7

maybe "P/10, with integrator" is the best one so far? Seems any increase in
P-gain always creates an ugly PN-bump?
Increasing the I-gain is maybe the next thing to try, either with a shorter
RC-constant, or by increasing the I-weight in the summing op-amp..
Didn't have time to read the references much - so this is mostly trial and
error for now...

Anders

On Sun, Feb 3, 2019 at 7:01 PM Tom Van Baak <tvb at leapsecond.com> wrote:

> Bert,
>
> That looks like a very nice board. Thanks for posting. Let us know how to
> obtain one; as board, kit or product.
>
> /tvb
>
> N.B. The original posting was aol / html. It has been reformatted below to
> work with the time-nuts server.
>
>
> ----- Original Message -----
> From: ew
> To: time-nuts at lists.febo.com
> Cc: j.koegel at bluewin.ch
> Sent: Sunday, February 03, 2019 5:26 AM
> Subject: Re: [time-nuts] OCXO PLL gains?
>
> There is a need for clean up loops across time-nuts applications. Right
> now Corby has one to test  clean up for a HP 5065A and a HP 5061B. How ever
> there is room for improvement.
>
> In my simple mind there may be an answer for most applications and enough
> brains among time nuts to define and develop a loop. Many of the telecom
> GPSDO's use frequency to correct for time, FE5680 a candidate even other
> Rb's depending what you have and try to accomplish. Morion MV89A, HP10811,
> Austron 1150, FRK, M100, FTS1200, M1000, OSA8600 all candidates for the
> other side.
>
> I recently did two OCXO boards one based on many time nuts inputs. Did not
> find some one to pick up the designs and make it available. I than decided
> to post Gerber files and based on off list questions and comments boards
> have been made.
>
> I propose something similar. Our experts come up with an answer, I do a
> board and add it to my next order, projects are waiting to be ordered after
> the Chinese holiday. As always Corby will along with Juerg get the first
> boards and once passed Corby's test I will release information. I do make
> layout mistakes and I do not want mistakes out there. Cause confusion with
> corrected boards.
>
> I keep looking at Microsemi 4145C datasheet and I am convinced with the
> time nuts brains out there one could get close. There is a digital loop
> between an the HP5071A and a OSA8600 and an analog loop between 8600 and a
> Wenzel Super Low Noise OCXO. Not now, walk before we run, but the brains
> and parts are out there.
>
> Bert Kehren
>
> Attached a picture of our first board, we now have later versions, one
> based on Wenzel 600 sec. design and one similar to the dither filter used
> in the HP GPSDO. We are not experts.
>
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