On Tue, Jul 7, 2009 at 08:14, Firas A.<[email protected]> wrote:
>...some digital modulations (for example GMSK) > reception can be improved by using a scrambling engine which is something I > used before many years ago to improve data reception circuitry performance. Pseudo-randomizing bit sequences to prevent long runs is a standard radio technique, as you mention. GNU Radio has gr.scrambler() and gr.descrambler() blocks to do this. The first takes unpacked bits in and feeds them through a configurable LFSR; the second undoes this operation to return the original bits. See the 'digital-bert' example for how this is used to test the bit error rate of a BPSK channel. In the example digital packet radio application, we instead use a whitener that has a pre-generated sequence of bits that we XOR the payload with. Johnathan _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
