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Re: [Discuss-gnuradio] rx_ofdm example
From: |
Michael Dickens |
Subject: |
Re: [Discuss-gnuradio] rx_ofdm example |
Date: |
Tue, 26 Sep 2017 08:35:06 -0400 |
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
> >
> > _______________________________________________
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> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
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