Hi Let’s hope Santa does not bring you an X10 power line based remote control system for Christmas….
Bob On Nov 18, 2013, at 5:15 PM, Tom Van Baak <t...@leapsecond.com> wrote: > Magnus, > > I'm going to push back a bit on your mains sampling claim. Mostly, I'd like > to see the results of the professional I-Q demodulated gear that you > mentioned. Can you post raw data, or a sample plot? > > I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is > going to reveal interesting amplitude and phase noise information. But see > how well a $1 PIC can do. > > Attached is a plot made using TimeLab + picPET just now. The picPET is fast > enough to capture the zero-crossing of every 60 Hz cycle with 400 ns > resolution; the TimeLab plots have tau0 of 16.67 ms. > > -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET > though a 10k resistor. > -- The pink trace was adding a 10 nF cap across the input. > -- The green trace was unplugging my laptop switching power supply from the > same outlet! > -- The red trace is replacing the mains wall-wart with a hp 33120A set to > 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used > this way. > > My conclusions are that at least here in the US, or at least at my house, the > short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The > attached short-term plot is also not-inconsistent with the long-term plot at > http://leapsecond.com/pages/mains/ > > My other conclusion is that the picPET (a simple PIC-based time-stamping > counter) is doing a pretty good job measuring this. Note, no software or data > filtering was used. This is just raw serial/USB data going into TimeLab. > > /tvb > <mains-picpet-04.gif>_______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
