Hi Shi - I'd recommend you find and review the paper cited in the S&C OFDM sync block's info:
Schmidl, T.M. and Cox, D.C., "Robust frequency and timing synchronization for OFDM", Communications, IEEE Transactions on, 1997. I'm guessing it will describe in detail what you're looking for. Hope this helps! - MLD On Tue, Sep 26, 2017, at 08:18 AM, Shi Yang wrote: > I read the page about schmidl&cox ofdm synch. block and now I know the > frequency mod block is here to normalize the fine frequency offset. > But why the sensitivity is -2/fft_len instead of 2/fft_len? Can > somebody explain that to me? > And I still did not understand what are the delay and multiply block > for. > While I was writing this email it hit me. The negative frequency > offset is multiplied with the data stream for the fine frequency > correction. Is that right? But why is the delay block necessary? > Best regards, > Yang > On Tue, 26 Sep 2017 14:01:29 +0200 > "Shi Yang" <[email protected]> wrote: > > Hi folks, > > > > I have a question about the rx_ofdm example. I have read the packet > > data transmission page on gnuradio.org > > (https://gnuradio.org/doc/doxygen/page_packet_data.html), but did > >not > > find the answer I wanted. The schmidl&cod ofdm synch. block outputs > >the > > frequency offset to a frequency modulation block. I did not get the > > purpose of frequency mod, delay and multiply blocks. what is the > > output after multiplying the signal delayed by one symbol length > >with > > the frequency modulated offset? And when using this part in my own > > flow graph, how should I set the value of sensitivity? > > > > Thanks in advance and best regards, > > Yang > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > [email protected] > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
