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Re: VLF: Transatlantic messages at 8822Hz

To: [email protected]
Subject: Re: VLF: Transatlantic messages at 8822Hz
From: Paul Nicholson <[email protected]>
Date: Tue, 06 Jan 2015 12:01:13 +0000
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I made a spectrogram from the reconstructed carrier
(the BPSK modulation removed by undoing the phase reversals).

 http://abelian.org/vlf/tmp/150106a.png

The bin bandwidth is set to the bandwidth of the information
bits.   I think this demonstrates quite dramatically the strength
of the forward error correction coding.

It is remarkable and quite fascinating that 150 bits of information
can be obtained error-free from that feeble looking trace on the
spectrogram.

Without undoing the modulation, the signal is spread over a bandwidth
of about 0.125Hz and is completely invisible.

--
Paul Nicholson
http://abelian.org/
--

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