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

[Bob kb8tq]

Hi

The gotcha these days is that MCU hardware just keeps getting cheaper
and cheaper. You can get a quite adequate MCU to do all this for less than
the price of your 1496 …. Yes, that’s nutty, but it’s the way pricing works
these days.

Worse yet, you can get a Chinese assembly house to supply that CPU on a 
board for you (along with various small parts) and still not have spent very
much at all for the parts plus the board. The ~$25 shipping likely will cost almost
as much or more than a handful of assembled boards. Again, it’s a nutty world.

Bob

> On Aug 1, 2020, at 1:45 PM, Tim S <tim.strommen at gmail.com> wrote:
> 
> 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.
>> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.