[time-nuts] Re: What phase variations to expect in a DMTD due to temperature fluctuations?

[Erik Kaashoek]

The down converted input signals are converted to digital using an ADC. The
rest is DSP. No digital circuit triggering timers. Can the clock of the MCU
still have an impact? For sure the clock of the ADC can have an impact.

The mechanics are very nasty. No touching of the table with the DMTD on it.
Worst are the coax cables. BNC connectors are terribly unstable.

Is 1 to 10 ps to be expected in the electronics? Or should I invest in semi
rigid coax?
Erik

On Sun, Oct 23, 2022, 21:58 Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:

> --------
> Erik Kaashoek via time-nuts writes:
>
> > The rest is digital and not expected to be temperature sensitive.
>
> At a 1ps level of interest, that is not a well-founded expectation.
>
> In particular look out for power-supply variations, which will transpose
> the trigger point for your "digital" clock-signals.
>
> PS: Do not ignore mechanics either: At the speed of light 1ps takes you
> only 0.3mm.
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>