[time-nuts] 60 Hz line quirks, anybody recognize this stuff?

[J. Forster]

IMO, you have an instrumentation issue. I don't think the power grid can
do anything like that.

YMMV,

-John

===============



> The context is using the 60 Hz line for timing.
>
> I'm feeding 60 Hz from a wall wart transformer into a modem control signal
> that the kernel PPS stuff watches.  Mostly, it works as expected, but
> occasionally, it picks or drops a cycle.
>
> In order to understand what was going on, I fed the same signal into the
> audio input and setup a job to capture the audio.  Here is an example of a
> pick:
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Aug-09-a-pick.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Aug-09-a0.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Aug-09-a1.png
>
> OK, that somewhat makes sense.
>
>
> Something happened several days ago.  I used to get picks/drops rarely,
> say
> ballpark of 1 a month.  Now I'm getting 10 or 20 per day.  So I started
> looking closer.
>
> I'm now seeing stuff like this.  I've got lots and lots of examples.  I
> added
> a second PC with different hardware.  It sees the same stuff.
>
> Does anybody recognize this?
>
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Sep-01-a0.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Sep-01-b0.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Sep-01-c0.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Sep-01-d0.png
> http://www.megapathdsl.net/~hmurray/time-nuts/line/2012-Sep-01-e0.png
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
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