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Subject: 
Re: Firmware: IR transmission demystified
Newsgroups: 
lugnet.robotics
Date: 
Tue, 10 Nov 1998 00:31:57 GMT
Original-From: 
Markus L. Noga <MARKUS.NOGA@spamcakeINRIALPES.FR>
Viewed: 
2806 times
  
I just checked http://cesdis.gsfc.nasa.gov/linux/misc/irda-details.html

The physical link layer is based on the common asynchronous serial
port, with a few adaptions. The serial port is set to "8N1", i.e. one start
bit, eight data bits, no parity, and one stop bit. The infrared transmitter
is off during the idle/"space"/1 state and -- in a deviation from wired
serial signaling -- on only 3/16 of the active/"mark"/0 bit period. This
reduced "on" period drops the power needed to transmit and moves the
emitted spectrum toward a higher frequency where it is easier to
separate from other IR sources.

If our baby can recognize those 3/16 marks as marks, and the other end
won't mind our transmitting 16/16 marks, perhaps.

http://cesdis.gsfc.nasa.gov/linux/misc/irda.html

IrDA physical layer specifies an IR LED with a peak output in range
from 0.85 um to 0.90 um. Many common IR devices are optically
suitable; a few advertised specifically as IrDA compatible are:

Also, IrdA goes up to from 2400 bps to 115 kbps in Version 1.0. We can
do 4800 bps max.

--
Markus L. Noga noga@inrialpes.fr
INRIA Rhône-Alpes http://www.inrialpes.fr/
IPR Universität Karlsruhe   http://wwwipr.ira.uka.de/



Message is in Reply To:
  Re: Firmware: IR transmission demystified
 
(...) Briefly remind me of what the IrDA signal is like and I might be able to answer. -Kekoa (26 years ago, 9-Nov-98, to lugnet.robotics)

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