Re: [Discuss-gnuradio] rx_ofdm example

[Michael Dickens]

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" <address@hidden> 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
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> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 
> 
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