On Tue, Jun 25, 2013 at 11:50 PM, Dan CaJacob <[email protected]> wrote: > I often have to test hardware RXs and though I have a hardware BER test > fixture, it's kind of ancient and difficult to work with. I have fantasized > about using a USRP to transmit a PRB (pseudo-random bit-sequence) to a RX > modem. The data would then be brought back into GnuRadio and compared with > the originally transmitted PRB to determine the actual BER. > > To align the data, I figured I could correlate the sent code against the > received data to determine any offset and align the data for comparison. > The correlation should be pretty forgiving to bit errors if the right PRB is > chosen, I think. > > My question is: does anyone have additional thoughts about this? I don't > think that this sort of tool exists yet in GnuRadio. I have seen BER tools > and even a nice BER block from Balint, but I think they all assume the data > is already aligned. I imagine that Balint's block could still be used if > the alignment was done first. Am I missing any other tools out there? > > As for getting the received data back into the flowgraph, I imagine that > this might require a new source, like a synchronous serial port. I have > used libmpsse to work with some of the MPSSE-enabled FTDI chips before. > Maybe that could be implemented as a source block. My other thought was to > use a LFTX board and bring in the clock and data as separate RX channels > then proceed from there. > > Thanks!
Hey Dan, That's a good problem. My only recommendation at this point is the correlate_and_sync block that I'm working on for burst modems. Started it at our last hackfest. You can find the code on my github repo (https://github.com/trondeau/gnuradio.git) in the 'grhack13' branch. It's working in a very specific case but is close to working generically. It sounds close to what you want. Tom _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
