11W is the power supply limit, not the radio power limit! Sorry that wasn't
very clear at all, however we do have another limit of 2W transmitted energy
on the radio, amongst other legal limits I still need to work through.

Mat

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Vasile Surducan
Sent: 15 October 2006 14:44
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Radio Synchronisation

11W inside of a building means suicide for the people living in the
office where the transmitter is installed.
I doubt he read the standard before claiming he can use 11W.
I even bet.

Vasile

On 10/14/06, Denny Esterline <firmware@tds.net> wrote:
> Maybe I missed something - this sounds too easy.
>
> Power at the transmitter is effectively unlimited, right? (o.k. 11 watts,
but that's still lots) Why not just send a time signal out continuously, and
let the receiver read it whenever it wakes up? The transmitted data stream
could be a time packet followed by some form of sync pulse - something like
$5A5A, then the reciever snychronizes with the next rising edge.
>
> I'm more interested in why the units need that level of sync.
>
> -Denny
>
>
>
>
> > I'm currently working on a design with a specific problem, which I'm
> > hoping someone will have come across before.
> >
> > Essentially I have several remote circuits, which must remain
unconnected.
> > They all need to be synchronised within 100 Micro Seconds.
> >
> > Essentially we are looking at deploying a beacon transmittor which will
> > send out a pulse at known intervals and have low power recievers on each
> > circuit which come out of hibernation at the required interval, to reset
> > the onboard clocks appropiatly.
> >
> > We are looking at achieving 100m range (indoors), however power at the
> > beacons is not a significant problem (we have 11Watts available, and
these
> > are not battery powered). Power at the recievers is crucial, each
circuit
> > is powered by battery and must be capable of running for a minimum
period
> > of a year. Physical battery size is not crucial but small is better :)
> >
> > Does anyone have any other suggestions how to achieve the required
> > synchronisation, or can anyone suggest any suitable radio IC's/circuits
> > which could be used as I am stuggling to find anything useful via google
> > (must be using the wrong keywords)
> >
> > Any suggestions or comments would be greatly appreciated.
> >
> > Mat
> >
> >
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