If you turn the FFT averaging up to maximum and wait a little while, the
carriers will stand out.
OFDM average
Ron
On 01/03/2016 05:03 PM, Aditya Virmani wrote:
Hello
Yes, I think this is the same thing I am trying to do, but I am not
getting the results I expected. Can you please share the GRC file for
this. In my execution, I was getting null signals.
You can see my setup in the attached file. It's a rather simple
version just for illustration. I don't understand why that is not working.
On Sun, Jan 3, 2016 at 7:45 PM, Ron Economos <w...@comcast.net
<mailto:w...@comcast.net>> wrote:
If you want to see individual carriers, you have to use a high
resolution FFT. Here's a 262144 point FFT on a DVB-T2 OFDM signal
with a 1K FFT (853 active carriers). The carriers are spaced about
9 kHz. Stronger tones are pilots.
https://twitter.com/drmpeg/status/670769195160858624
Ron
On 01/03/2016 04:34 PM, Aditya Virmani wrote:
Hello sir
Thank you for your reply. Well, I am trying to do some additional
operation to the receiver side of the OFDM transceiver (rx_OFDM).
I am intending to detect a doppler shift in the received signal,
for which I am trying to do an FFT over symbols collected in 1
second.
To test the case, I tried to do a large FFT over 4 same OFDM
symbols, which means a 4 x 64 FFT, which should give me 48
(corresponding to occupied tones) peaks instead of a band.
The theory of peaks can be illustrated simply by the FFT theory.
I can share the reference for that if needed.
I hope I am clear here.
On Sun, Jan 3, 2016 at 7:06 PM, Martin Braun
<martin.br...@ettus.com <mailto:martin.br...@ettus.com>> wrote:
Typically, you'd do 1 (I)FFT per OFDM symbol. I recommend
having a look
at the tx_ofdm.grc and rx_ofdm.grc examples, which show a
full flow graph.
M
On 01/03/2016 01:22 PM, Aditya Virmani wrote:
> Hello everyone
>
> Iam trying to do run-time FFT over multiple OFDM symbols.
> For this, I feed in the same sequence of bytes for each
OFDM symbol.
> As per my understanding, as I am feeding in the same
sequence of bytes,
> it should be generating same set of symbols, and then
further if we do
> FFT over multiple symbols which are same, we should get a
sequence of
> peak-and-zeros, instead of continuous FFT graph.
> This works fine if I do just with two symbols (screenshot
of that
> attached), but when I feed in more than two, it results in
error ( I
> think that the data doesn't reach the FFT block
concurrently, because
> the graph I get is same when I feed Null source and a
Symbol source to
> FFT).
>
> It would be great if someone can guide me with it.
>
>
> Regards
> Aditya Virmani
>
>
> _______________________________________________
>
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