Hi Eric, Thanks for your answer. I will take a look at that. I'll work hard to patch it. I promise, I need the USRP2 working fine as soon as possible. When I finish I'll send it gnuradio the patch.
Thanks for all help. Regards, Ronaldo 2009/3/25 Eric Blossom <e...@comsec.com>: > On Tue, Mar 24, 2009 at 04:03:36PM -0300, Ronaldo Nunez wrote: >> Hi folks, >> >> I tried to TX a FM modulated signal using USRP2 BasicTX. >> The signal was a 440 Hz sinusoid, and the carrier 1 MHz. >> I used the signal generator and fm modulator blocks provided by GNURadio. >> >> When I tx it the follow message appeared on the screen: >> >> USRP2::Tx_RAW: FIXME: short packet: 1 item (32 bytes) >> >> Sometimes the item number changes to 4 or 8... >> What that mean? >> >> I took a look at the usrp2_impl.cc (last revision) and i couldn't >> identify any problem... >> >> Any suggestion is welcome. >> Regards, >> >> Ronaldo > > Hi Ronaldo, > > There's a bug in the on-the-wire format for the USRP2 where we're not > currently transmitting the valid length of the packet. With ethernet, > the minimum packet size is 64-bytes, and there are some times where > the host code is naively fragmenting the received samples in a way > that produces a packet that is too short for ethernet. > > I've opened ticket:378 on this. It will be properly fixed when we > rework the on-the-wire format as part of the VRT work, but I think > there's an intermediate step that can avoid most cases of the problem > happening. I'm not sure that I can find time to fix this in time for > 3.2.0, but if you'd like to take a look at it, we'd love a patch for > it. What needs to happen is that the loop in usrp2_impl.cc(tx_raw) > that fragments the nitems items needs to be a little smarter about > breaking the items into ethernet frames. Each piece needs to be > between 9 and U2_MAX_SAMPLES samples long. (9 works out to the > smallest number of samples that plus the headers ends up being >= 64 > bytes). > > Eric > -- __________________________________ Ronaldo A. Viera Nunez Acadêmico/Engenharia Elétrica Universidade Federal de Santa Maria Santa Maria - RS - Brasil _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
