[time-nuts] Driving clocks from 1pps

[Tom Van Baak]

>> 50% duty cycle is way overkill, perhaps even harmful. In the
>> 'scope traces below you can see the IC generates just 50 ms
>> biphase pulses every second. That's 1/20, or 5% duty cycle.
> 
> No Tom, you misunderstand.  The 50% duty cycle pulse provides the
> rising and falling edges.  The small capacitor differentiates
> that to produce a positive going, or a negative going pulse to
> make the motor move.
> 
> -Chuck Harris

Ah, I see now. It's a 0.5 Hz square wave. Cool. Yes, that looks
like it might work. Has someone tried this on a quartz clock
stepper motor to make sure you reliably get sufficient impulse?
I wonder why no commercial clocks use this trick.

/tvb