[time-nuts] Quiet clocks, noisy clocks

[paul swed]

Ron
Not sure who it would be but the reason to want to use a 1 pps step is its
easy to clock.
Though the fact that its 2 phase like you have in the pulse makes it
tougher.
The tick is the second. On a multi-step clock how do you phase the second
hand. Visually but complicated through a slew method. Maybe optically but
it gets more complicated. If you have 4 clocks for ham radio it really gets
messy. So the 1 PPS keeps things reasonably aligned with little effort.
Digital clocks remove all this. But I guess I like the analogs.
Regards
Paul

On Sat, Jan 5, 2019 at 2:30 PM Ron Bean <time at rbean.users.panix.com> wrote:

> A recent thread talked about noisy clocks (1 tick per second). Some of
> you may have noticed that it's now possible to buy cheap quartz clock
> movements that have a continuous-sweep second hand, and don't tick once
> per second. For example, klockit.com sells two different brands (Seiko
> and Quartex, the latter is owned by the same company that owns klockit).
>
> AFAIK LaCrosse is the only company making consumer-level quartz clocks
> with this feature, and only on certain models. I've found that the
> plastic gears do make some noise, especially with a large clock face
> that acts as a resonator, and they may be audible in a quiet room. But
> IMHO they're less bothersome than 1 tick per second.
>
> A few years ago I put a 'scope on one of the Quartex movements (pic
> attached, same pic at http://www.panix.com/~rbean/clock/clock-01.jpg )
>
> Like other quartz clocks, they use a "Lavet" type stepper motor
> https://en.wikipedia.org/wiki/Lavet-type_stepping_motor
> But the electronic timing and mechanical gearing are different (16 pulses
> per second). The amplitude is equal to the battery voltage (I think I used
> a lithium primary cell, which is a slightly higher voltage than alkaline).
>
> Some time ago, someone on this list mentioned that he knew someone who
> worked with the controller chips in cheap clocks and watches. If anyone
> knows which chip runs these things, I'd love to see a data sheet. They
> seem to keep remarkably good time for something that costs so little.
>
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