[time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

Gerhard Hoffmann dk4xp at arcor.de
Wed Sep 21 19:37:02 EDT 2016


Am 22.09.2016 um 00:24 schrieb Bruce Griffiths:
> Another issue is the requirement to trim the current sink for low output
> offset.

And _that_ FET is made from Unobtainium.
> If one takes advantage of the fact that the PLL imposes a low
> frequency cutoff to the PN measurements, the amplifier input   can be AC
> coupled, allowing dc bias feedback to be applied to the input device gate.
> Use a parallel dc coupled JFET input opamp for the PLL
That's what I did. Original Burr-Brown opa2134, time to use them up..
> Paralleled BF862's can be substituted for the input JFET.
>
Yep!



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