On Mon, Oct 1, 2012 at 12:00 PM, Nazmul Islam <mnis...@winlab.rutgers.edu> wrote: > Hello, > > Frederic Harris's "Multirate Signal Processing: for communication systems" > has a section on FLL band edge sync. I think that the GR-digital code was > designed based on these algorithms. Tom or other GNUradio block designers > can verify it. > > Thanks, > > Nazmul > > On Mon, Oct 1, 2012 at 11:40 AM, Martin Braun (CEL) <martin.br...@kit.edu> > wrote: >> >> Hi, >> >> is there any literature that goes with the FLL synch blocks in >> gr-digital? Ironically, Google always points me to the GR source files >> when I search for 'fll band edge' related topics. >> >> M
Martin, Yes, harris' book is the best to start with. There is another paper from him called "Let's Assume the System is Synchronized" that also goes over it. I'm not sure if he's published a paper that discusses the specifics of the filter derivation, yet, though. It's based on the derivative of the half cosine waveform of the RRC filter rolloff. The system behaves much better this way than just generating any random band edge filter. In theory, this should work for any signal using an RRC pulse shaping. For specific constellations, you could use a Costas loop with a wider lock in bandwidth to handle the frequency offset. Oh, and I might be the only one who calls this the "FLL band edge filter" specifically to point out that this is only one possible implementation of an FLL for coarse frequency tracking. Other algorithms are welcome :) Tom _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
