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

Bill Dailey docdailey at gmail.com
Sat Sep 1 22:21:18 UTC 2012


Firefox is notorious for screwing up audio in windows.  I have had OS of problems with this.  I actually think its something o o with networking.

Sent from my iPad

On Sep 1, 2012, at 5:16 PM, Chuck Forsberg WA7KGX N2469R <caf at omen.com> wrote:

> On 09/01/2012 02:17 PM, Magnus Danielson wrote:
>> On 09/01/2012 08:35 AM, Hal Murray wrote:
>>> 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
>>> 
>>> 
>> 
>> It's interesting to notice that you have about the same distance from the middle in all 5 examples. It's like you trigger a diode drop for a while. Notice that there is a small slope towards zero.
>> 
>> Cheers,
>> Magnus
>> 
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>> 
> I have noticed many stalls in Windows lately, possibly the result of Flash and Firefox not getting along.
> The first plot suggests a multitasking related problem.
> 
> -- 
> Chuck Forsberg WA7KGX N2469R     caf at omen.com   www.omen.com
> Developer of Industrial ZMODEM(Tm) for Embedded Applications
>  Omen Technology Inc      "The High Reliability Software"
> 10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430
> 
> 
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