[time-nuts] 60Hz extra PPS: got one

Hal Murray hmurray at megapathdsl.net
Fri Aug 10 17:37:09 UTC 2012

bill at iaxs.net said:
> Hal, do you have a resonant 60 Hz filter in the pickoff?

Not by intent.  It's just a wall-wart transformer and then some resistors to 
get the right level.  There are the standard cables (wall wart, RS-232, 
audio, clip leads).  I'm sure there are resonances in there but nothing near 
60 Hz.

> Remote-controlled tap changers can do things like that.

Bingo.  Thanks.

Here is a graph with the vertical scale zoomed in on the top of the sine 
peaks so you can see the voltage step.

> I expect you'd rather do things in software, but the mechanical solution is
> to couple a synchronous motor to a flywheel marked with 60 Hz lines for
> photocell pickup.

Good idea.  Or an old clock motor.  Do they still make motor driven clocks?  
The kind with the flag that drops down and turns red on a power loss rather 
than blinking 00:00.

I should be able to do something with a simple L-C.  I'll have to check the 

These are my opinions.  I hate spam.

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