Hi, Tom I am not quite understand the ofdm_sync_xx.cc in python/gnuradio/blks2impl/.
What is the difference between frequency synchronization and carrier frequency offset. Why we have to do the timing and frequency synchronization before it? Thanks, Guanbo Tom Rondeau wrote: > > On Tue, Feb 16, 2010 at 5:45 PM, Srinivas <psriniva...@gmail.com> wrote: >> Matt, >> >> Thanks for verifying the data rate calculation! >> >> I tried the other solutions that you suggested, namely, >> >> - increasing the data rate by a factor of 2 or 4 >> It works. >> >> - modifying the OFDM code to widen the search range - How do I widen the >> search range ? >> Should I be looking in the "ofdm_sync_" blocks in "blks2impl" folder ? If >> yes, which synchronizer is currently used with ofdm_examples ? > > You need to add an argument to gr.ofdm_frame_acquisition in > ofdm_receiver.py (in python/gnuradio/blks2impl). > > In the current Git master, this is located on line 109 of > ofdm_receiver.py. After the "ks[0]" argument, you can put in an > integer. This is the maximum number of bins the receiver will search > over for correlation. It defaults to 10. > > >> - locking the usrps to a common reference >> My usrp2s are located wide apart so I guess this solution is not >> practical. >> >> Besides, this confirms that the problem is somewhere in the USRP2 board, >> right ? (as I tried swapping the daughter cards & firmware with the >> working >> pair) >> >> Thanks, >> Srinivas > > Nope, this is typical of radio hardware. They are always off > frequency. If two oscillators are off frequency and then multiplied up > to another frequency, the difference will also be magnified. So a 2.4 > GHz board will have a larger frequency offset than if you ran it just > through the BasicTx/Rx boards (even though the ratios should be the > same). > > Tom > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://old.nabble.com/OFDM-receiver-on-USRP2-tp27557644p30658514.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
