"Roland Perry" wrote in message
...
In message , at 04:57:25 on Tue, 17 Mar
2015, john james remarked:
If you have one TV whose contribution to the power consumption is:

*** *** **** **** *** *** ***
*** *** **** **** *** *** ***
-----------------------------------------

and another whose contribution is:

* * * * ********* ************ * * *
* * * * ********* ************ * * *
* * * * ********* ************ * * *
-----------------------------------------

then the total is:

* * * ***** ** *** ** * *
* * * ***** ** *** ** * *
* * * * ********* ************ * * *
*** * *** ********* **************** ***
*** * *** ********* **************** ***
-----------------------------------------

But there is no way to go from the last one to the first two.

There is. You take the "pattern" from a TV programme currently being
broadcast, and subtract it from the total.

You can't do that when the total house power
use is only measured every 4 seconds.

You ten see if what remains
matches any of the other TV programmes currently being broadcast.

If it doesn't batch, then try a second TV programmes... iterate until
you find two whose patterns do add up to the total.

Just not feasible with 100 or more broadcast channels and a
4 second sample time of the total house power consumption.

I'd expect to be taking perhaps 100 measurements of the house,

Smart meters don't provide samples of the current consumption
of the house, they integrate the total current consumption and
report that at a few instances a day.

and
obviously having some central apparatus taking 4-second samples from all
the TV channels to compare those with later.