[Ronja] Analogue silly question...

[matt]

I understand that ronja currently uses a pulsed encoding that means that you cannot push ofdm over it as is.

My question is more a can you not drive the laser in varying strengths ?

My
understanding of the limitations are that they are in the "how do you
know what power you should have" at the receiver as a baseline for
decoding an analogue encoded transmission.

It's my thinking that this problem has already been solved with the wifi radio design.

So can the rx and tx of a ronja "like" system be analogue ?

If so does the encoding present any speed benefits or greater "spectrum" efficiency ?

I know nothing and every question I ask proves it.

Cheers

Matt

P.S.
On further reading I realise that the maximum available bandwidth for the tx design is currently about 16Mhz - just enough for 10Meg.

With analogue using 50% power as the centre of the frequency with +/- 25% as the gives a required change of 50% which should increase the bandwidth to 32Mhz (with 54g @ 20Meg needing 22Mhz).

As far as I can see the limit would be with the rx unit sensitivity..........

----- Original Message -----
From: Patrick Deelman <morphje at morphje.nl>
Sent: Fri, 8/2/2008 04:26
To: matt <matt at vitalit.co.uk> ; Twibright Ronja <ronja at lists.pointless.net>
Subject: Re: [Ronja] Analogue silly question...

matt wrote:
> Hi all,
> Before I even ask it I know this must be a stupid question....
>
> The issue of using analogue transmission has been asked and answered before.
>
> My question however is thus :-
>
> Is is not possible to hack apart a wireless access point (a GPL friendly one such as the wrt54gl) and drive the laser from the radio interface's tx and interface the rx ?
>
> This should resolve the power calibration issues as this will have already been designed for in the radio interface.
>
> Could this not provide a cheap way to get faster (22meg+) links ?
>
> Now please tell me where I've gone wrong ......
>
> Cheers
>
> Matt
>
>
>   
This will not work, since a 802.11g access point uses OFDM for the 
modulation of the signal, this is incompatible with ronja. Also signal 
feedback for power calibration (for reducing link speed) will not work, 
since this is indended to work with radio signals and not ronja, simply 
because with ronja you get it all or you get nothing. With radio signals 
you get more when the signal strength increases, thus less noise, so you 
can modulate more on the frequency.

Regards,
Patrick