[time-nuts] time-nuts Digest, Vol 193, Issue 1

[Tim S]

I would also suggest that a simple frequency doubling if using a
differential output op-amp is too hard would get one there.  Something like
a balanced lm/mc1496 mixer will double the input frequency if the inputs
are the same.

IMHO it's tempting to use software where simple (cheap! LM1496 is about
$0.80/each on Digikey) analog hardware will do the trick.  But it's the
same math whether an analog circuit is doing it by design or if software is
doing it.

-T

On Sat, Aug 1, 2020, 09:00 <time-nuts-request at lists.febo.com> wrote:

> Date: Fri, 31 Jul 2020 21:00:13 +0000
> From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
> To: Discussion of precise time and frequency measurement
>         <time-nuts at lists.febo.com>, Bob kb8tq <kb8tq at n1k.org>
> Subject: Re: [time-nuts] WWVB PM Time Questions
> Message-ID: <85171.1596229213 at critter.freebsd.dk>
> Content-Type: text/plain; charset="us-ascii"
>
> --------
> Bob kb8tq writes:
>
> >The WWVB modulation is *very* predictable. Once you have lock,
> >you can guess just about every phase reversal you will see.
> >[...]
> >The point of this being that you *could* pre-flip the data before it
> >went into a buffer. That way the buffer integration time constant
> >could be quite long.
>
> I would just use two buffers and decide which one based on the
> prediction, that way DC-offsets will not cause trouble.
>
> --
> 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.
>