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List: gnuradio-discuss
Subject: Re: [Discuss-gnuradio] QPSK with direct-sequence spread spectrum
From: Peter Massam <peter.massam () plextek ! com>
Date: 2011-10-31 17:59:06
Message-ID: 32754111.post () talk ! nabble ! com
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In general you're right, but it depends on the details. Its usually quite
straightforward, but a common mistake is to use the wrong bit-to-symbol
mapping. 0 -> +1 and 1 -> -1 means that an XOR applied to bits is
equivalent to multiplication applied to symbols.
Nowlan, Sean wrote:
>
> Hi all,
>
> I'm wondering if spreading a bitstream (XOR-ing each bit with
> SPREAD_FACTOR bits of sequence) before QPSK modulation is equivalent to
> operating on the modulated stream, i.e., multiplying the complex output
> with -1's and 1's from the sequence. So far I can't get the math to work
> out. Any suggestions?
>
> Thanks,
> Sean
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
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