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

J. Forster jfor at quikus.com
Sat Sep 1 13:41:58 UTC 2012


I'd try to beg or borrow a line dsturbance monitor. To me, it looks like a
SW issue, BTW. Perhaps something like an interrupt service routine crock.

FWIW,

-John

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


> I agree: I don't think this is possible on a power line. Better to use a
> second sampling unit to check.
>
> On Sat, Sep 1, 2012 at 3:30 PM, J. Forster <jfor at quikus.com> wrote:
>
>> 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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>> >
>> >
>>
>>
>>
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