On 22.05.2015 10:54, Michal Vaclík wrote: > Yes, I am using default flowgraphs (examples) just adding Multiply Const > block to avoid clipping due to high PAPR and obviously UHD blocks. Using > FFT of 64 and default carrier configuration, sync does get better if I > stretch this to wider bandwidths by setting higher sample rates at USRP.
Hey Michal, I meant using the same signal bandwidth at higher sampling rates (i.e. bigger FFTs, same number of occupied bins). M > > 2015-05-21 18:13 GMT+02:00 Martin Braun <martin.br...@ettus.com > <mailto:martin.br...@ettus.com>>: > > On 20.05.2015 20:19, Michal Vaclík wrote: > > Hi, I am sorry for the delayed response. > > > > I checked the centering of the OFDM signal and it looks pretty good. > > Even looking at the signal's spectrum using SDR# on other computer was > > very nice - book-grade example of nicely shaped OFDM spectrum. Today I > > upgraded from GNU Radio v 3.7.6.1 to 3.7.7.1 and reception > > (syncrhonization and detection) has improved dramatically. Even at > > relatively low sample rate (1M, anything lower simply doesn't > > synchronizie). Unfortunately the received packets still weren't enough > > for any kind of real world transmission. > > > > Was OFDM improved in some kind of way in v3.7.7.1 (I don't see anything > > related to OFDM in changelog)? I simply launched the same flowgraph on > > newer version and it works much better. > > Hm, not that I recall... but good for you :) > > I forget, were you using the example codes with default settings? If so, > does doubling the sampling rate *without* changing the total bandwidth > (i.e. doubling the FFT size) help with sync at lower bandwidths? > > M > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
