this would be similar to 802.11b's PHY at 1Mbps, except it uses the barker sequence as opposed to the sequence you mention. It spreads a BPSK signal using the barker sequence.
You can take a look at the BBN 802.11b code in CGRAN to see how they implement this: https://www.cgran.org/browser/projects/bbn_80211/branches/usrp2_version/gr-bbn/src/examples/bbn_80211b_pkt.py#L126 It modulates to BPSK, and then spreads it out via the interpolation filter. - George On Wed, Apr 28, 2010 at 12:19 AM, John Andrews <gnu.f...@gmail.com> wrote: > Hi, > If I want to transmit a signal which is DSSS spread using BPSK. Is it > correct for me to first digitally spread the incoming data bits and then > apply BPSK before sending it to the USRP or should I first convert the > signal to BPSK and then multiply the output of the BPSK modulator with the > PN sequence although I don't know how to do it. > > 1. If '1' is the data bit then convert it to '1010100111' (lets say this is > the PN sequence) and then input it into a BPSK modulator. > 2. If '1' is the data bit first input it into a BPSK modulator and then > mutiply the interpolated output with the PN sequence. > > Theoretically, these two methods will lead to the same result but I am not > sure how to do this in gnuradio. > > Any ideas? > > Thanks > John > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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