----- Original Message -----
From: Jilles Oldenbeuving <jilles@RENDO.DEKOOI.NL>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, June 14, 2000 11:03 PM
Subject: Re: [EE]:Telemetry encoding


> Actually, i'm busy with it too right now! (Let's start a Telemetry
encoding
> list <g>)
> Only, i'm decideing at the moment wich radio module to use... I've got
some
> parts from Quasar (www.quasar-ltd.com) and RF Solutions. Didn't buy any
> Radiometrix modules, becouse the price is to high for my mid-quantity
> application.
> Anybody has some good suggestions on what to use?
>
> I've also looked at the radiometrix site at that info you're talking
about.
> What scheme will
> you be useing for the telemtry encodeing? (or what scheme's have others
> used with succes?)  I think one also has to implement a CRC-check. For my
> testing purposes i'd thought about the summing-check (just sum all the
data
> you want to send, without respect to the carry bit). But after diving into
> the
> matter more closely i'd say one has to use a real CRC-check (dividing the
> data with a "poly", or whatever). I'm not sure how i could treat the 6
> databytes
> i want to send as a long series of bits wich will be devided by the poly
in
> an
> effecient way.....
>
>

I`m not sure about the modules that you are using but the radiometrix ones
work best on a 50:50 mark space ratio. I think you would probably get better
data rates if your error checking scheme tried to maintain this.. Possibly
using a parity bit to make each byte 50:50?? Not really sure, when I have
sorted mine I will post some code.