[LAU] Looking for Audio Watermarking Advice & Tools

[Fons Adriaensen]

On Thu, Oct 27, 2011 at 11:47:07AM -0400, Monty Montgomery wrote:
> >> At least in NA, mains frequency is very very stable. The entire
> >> continent is in phase and clocked with very high precision.  It's more
> >> stable than a free-running digital clock.
> >
> > Yes, the long-term stability will be very good, as the frequency is
> > adjusted to keep clocks in sync. But there are small short-term
> > variations all the time which you won't notice on a clock, but can
> > be measured easily.
> 
> Really? Any supply that's out of phase will instantly face the wrath
> of the collective rest of the system.  "boom".  The whole continent
> would have to be moved simultaneously.

More or less, yes. But since the grid is not a zero-impedance
connection of everyone to everyone, phase errors (and therefore
small temporary frequency errors) can exists between distant
areas on the same grid. See for example
<http://fnetpublic.utk.edu/anglecontour.html>

Ciao,

-- 
FA