[time-nuts] Receiving the MSF time signal on cheap radio modules

[Deirdre O'Byrne]

No doubt! But I'm trying to remain as inexpensive as possible.

That it might be possie to get 5ms (300 carrier periods!) from an
off-the-shelf consumer-grade component not designed for accuracy is pretty
cool IMO.


On 7 Feb 2018 14:31, "Bob kb8tq" <kb8tq at n1k.org> wrote:

Hi

Back in the era of VLF disciplined oscillators, carrier phase was the
preferred approach.
Getting that to work with 100% AM modulation took some effort ….

Bob

> On Feb 7, 2018, at 2:13 AM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
>
> --------
> In message <CAGJ4F+697SyXwm3yWG-XczN4zF7r2RAmXzAcEm=dhaqBJc_
NNw at mail.gmail.com>, "Deirdre O'Byrne" writes:
>
>> MSF disciplined oscillator?! I don't trust these receivers to any better
>> than about the 20ms mark, so such a disciplined oscillator would have
quite
>> a long integration time!
>
> It's actually more complicated and better than that.
>
> The low-pass filter dominates, so the falling flank at second N
> depends on the pulsewidth at second N-1.
>
> I can't remember the numbers I got when I "sorted" DCF77 pulses depending
> on the previous pulse being short or long, but it was a fair bit better
> than 20ms.
>
> --
> 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.
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