So would a good solution to this be the packet encoder and packet decoder blocks? Since they utilize a preamble and access code? I tried to use the simple framer block in conjunction with the unpacked to packed byte block but was unsuccessful in getting a matching output, I will continue to play around with that configuration but for now do you think the packet encoder route would be a good solution?
Again, I really appreciate everyone's willingness to help. Logan Washbourne Electrical Engineering Graduate Student (Electromagnetics) On Tue, Jun 16, 2015 at 10:14 AM, Tom Rondeau <t...@trondeau.com> wrote: > On Tue, Jun 16, 2015 at 11:01 AM, Washbourne, Logan < > lwas...@ostatemail.okstate.edu> wrote: > >> Hello, >> >> I know a similar question has been asked before on this mailing list but >> I didn't quite get a solution out of it. I am generating a random byte >> source, either ones or zeroes, modulating them with DBPSK and immediately >> demodulating them. The problem I am running into is that I get roughly 8 >> times the number of bytes out of the demodulation block than I am inputting >> into the modulation block. I believe its a packed vs. unpacked byte problem >> but every attempt at packing the output bytes yields an output that doesn't >> match the input. >> >> Attached are the GRC file, and the output file streams. >> >> Does anyone have any suggestions? I appreciate all of your time, >> >> >> >> Logan Washbourne >> Electrical Engineering Graduate Student >> (Electromagnetics) >> > > > The problem is that you don't know which bit to put where in the byte. So > just packing the output bits into 8 bits per byte doesn't necessarily give > you the right information. Say you transmit a byte with bits [a b c d e f g > h]. After the delays introduced by the transmit and receiver filter and the > channel, when you pack the results, you could get something like [x x x a b > c d e] [f g h 0 0 0 0 0], for some unknown number of x's. > > You need some logic that knows how to discover the start of your > information and get rid of those x's. The framer blocks do this with some > assumed formatting and expectations. Johnathan and I have been working on a > better version of this, but we haven't had a chance to finish it off. > > Tom > >
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
