[time-nuts] 60 Hz line quirks, anybody recognize this stuff?
tcurlee@sbcglobal.net
tcurlee at sbcglobal.net
Sat Sep 1 19:31:48 UTC 2012
Perhaps a dumb question, but the wall wart is plugged into the wall, connected directly to the grid? You aren't powering the wall wart through a UPS or some type of inverter?
Tom
Sent from my HTC Inspire™ 4G on AT&T
----- Reply message -----
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Subject: [time-nuts] 60 Hz line quirks, anybody recognize this stuff?
Date: Sat, Sep 1, 2012 11:42 am
Hal, where are you taking off the signal to the audio line?
At the low voltage wall wart or at the modem pin? - assuming
there's an isolation or dropping resistor.
I agree with others that the power company isn't doing this.
There would be inductive ringing. Can you confirm with another
wall wart going right to another audio channel? Or maybe a
real filament transformer instead of a wart.
Who knew you could find so much interesting stuff on the power
line . . .
Bill Hawkins
P.S. I think the mild flattening of the sinusoid peaks is
caused by saturation of the barely-enough-iron in the wart.
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Hal Murray
Sent: Saturday, September 01, 2012 1:35 AM
To: time-nuts at febo.com
Subject: [time-nuts] 60 Hz line quirks, anybody recognize this stuff?
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
--
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