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

Magnus Danielson magnus at rubidium.dyndns.org
Sat Sep 1 21:14:23 UTC 2012


On 09/01/2012 10:57 PM, J. Forster wrote:
> Nope.
>
> The rise/falls are far too fast for anything connected to the grid even if
> in the same house. If the thing is on the output of a UPS with a rapidly
> switched load, maybe.
>
> Any big loads, even ohmic heaters, have some inductance. I don't see any
> such influence.
>
> Try an oscillator. I suggested an HP 200 series because they have big
> output, comparable to the line. Furthermore, it's impossible for such a
> unit to produce an output step, if it's working right. And they are very
> cheap.
>
> A simple phase shift oscillator with one transistor would work also. I's
> not use anything digital, like a DDS.

I agree that you really need to check your measurement setup. The grid 
doesn't do these things, possibly something in the house, but your 
measurement rig is under suspicion.

Professional gear for measuring power lines has filtering, so anything 
similar to this would be considerably smoothed out and not look like 
this. While professional gear has it challenges, they are beyond these 
issues.

So, do look careful at your setup. Loose connections, intermitent 
connections in IC holders, stuff like that. Bad timing for the ADC. 
Interrupt processing, ANYTHING.

Cheers,
Magnus



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