Marcus Müller <marcus.mueller <at> ettus.com> writes: > > Hi DingJing, > > I'm not sure what's going on here, but I think it could be likely that > your estimate of the preamble-autocorrelation simply doesn't work all > too well. > > Generally: ditch benchmark_rx and the blocks it uses. They are really > superseeded by the OFDM blocks that were introduced in 2013 – they are > far better, and also, will simply give you the estimates you want, I think. > > Make sure you have a recent version of GNU Radio, and look for the > rx_ofdm.grc example (likely somewhere in > /usr/share/gnuradio/examples/digital/ofdm). The "Schmidl & Cox OFDM > synch." block /actually/ has an output "freq_offset", and the "OFDM > Channel Estimation" block adds a stream tag containing the full > subcarrier offset (if any). ** > > Other than that: > > I've been trying to figure out the frequency offset of USRP recently. > Could you specify this a bit more? > > Best regards, > Marcus >
Dear Marcus Müller: Thank you for you reply. I just try out the benchmark in /usr/share/gnuradio/examples/digital/ofdm with little modification. As you known,the benchmark use ofdm_sync_pn by default for synchronisation.The "ofdm_sync_pn" block uses a block named "sample_and_hold" which I think is the value of fine_offset,so I created a block_file_sink and wrote "self.connect(self.sample_and_hold,self.offset_file_sink) " to output the offset value instead of set logging=Ture.Maybe I have some misunderstanding. Best wishes~ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
