[Moved to list, following my own recommendation ;)] Regarding: searching for normal and conjugated match in gr_correlate_access_code.
On Wed, Jun 28, 2006 at 05:03:09PM -0400, Tom Rondeau wrote: > > > > > This is OK, but there's a much simpler, and faster way to handle the > > problem. > > > > There's no need to check for the conjugate directly, or to run > > multiple shift registerrs. Just look at the hamming distance. E.g., > > a perfect match of the conjugate will have the maximum hamming > > distance, whereas a perfect match of the normal access will be 0. > > But if we have a threshold value for the conjugate, (max-threshold) would > trigger on a number of wrong solutions, wouldn't it? We would pass anything > up that has between 52 and 64 bit errors in the access code. If you're doing simultaneous detection of the normal & conjugate by any method, you've got the same problem. Note that this is a good reason *not* to enable both normal and conjugate when using DPSK. Say the access code was 10 long, and the threshold was 2. When detecting both, the map goes like this: hamming dist result ------------ ----- 0 Normal match (perfect) 1 normal match (one off) 2 normal match (two off) 3 -- 4 -- 5 -- 6 -- 7 -- 8 conj match (two off) 9 conj match (one off) 10 conj match (perfect) Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio