Martin, I think my question would have been clearer if i had said that when I talk of symbol rate I do not define a symbol to be the OFDM symbol of length fft_length+CP_length, but its fft_length+CP_length components.
So for me symbol rate is symbol_rate = (fft_length+CP_length) x OFDM_symbol_rate The grc examples are defining this as the sample_rate, which implies that they use one sample for each symbol (my definition). In any case, from your answer I understand that the S&C operates on ONE sample per symbol (my definition). --- I still have trouble getting anything out of the S&C synchronizer: The frequency offset output responds as expected when i introduce a freq error but the "detect" output does not give anything out even with noiseless input... I have uploaded the follwoing grc files http://web.eecs.umich.edu/~anastas/gnuradio/tx_ofdm2.grc http://web.eecs.umich.edu/~anastas/gnuradio/rx_ofdm2.grc which, illustrate my point. Any thoughts? thanks for the help, Achilleas On Sun, May 19, 2013 at 11:45:42PM -0400, Achilleas Anastasopoulos wrote: > I am having trouble setting some parameters and getting anything out of it... > > In particular > > in ofdm_rx > > 1) is the processing done on an 1 sample per symbol basis at the Scmidl&Cox ? I don't understand the question. The correlator has no info about OFDM symbol boundaries. > In that case the input sample rate has to be set to the symbol rate? > (what is called samp_rate in ofdm_tx) This is the input sample rate. The bit rate depends on the number of carriers used, the length of the CP and the modulation type on the payload. The OFDM symbol rate is the sample rate / (fft_len + cp_len). _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
