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Subject:	Re: [geda-user] [OT] Wireless communication 101
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From:	"Dave McGuire (mcguire AT neurotica DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Date:	Wed, 23 Sep 2015 15:52:57 -0400
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On 09/23/2015 03:30 AM, John Griessen wrote:
>> What I'm looking for are any texts or references that discuss the
>> principle of digital encoding for wireless transmission, which
>> algorithms and strategies are used in what circumstances and why. As I
>> said, I can't influence the RF part, only the ones and zeros that are
>> encoded onto the carrier. I also can't change at this stage the
>> simplex operation.
> 
> I don't have a reference, but I've heard that reed solomon encoding has
> been used by nasa for telemetry
> to get signals through under the noise.

  Reed-Solomon is a FEC (Forward Error Correction) algorithm that embeds
enough error correction data in the bitstream to be able to fix some
errors on the receiving end without retransmission.  It doesn't really
do much for the noise floor.

  That said, though, it's an excellent suggestion.

  One other thing to do is bit-stuffing to maintain DC balance.  That's
particularly important if the modulation is FM and the RX-side RF tuning
is automatic.  A time-averaged DC value of 0 is very important in that case.

               -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA

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