Re: [Discuss-gnuradio] OFDM TRANSFER and RECEIVE IN GRC

[Marcus Müller]

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Thinking about this, that was a bad question from my side.
Since the ofdm_mod doesn't even *know* about the center frequency, the
signal generated digitally is always the same, so you can only be
looking at the rx side's abs(FFT). Would be nice if you had a
description of what happens or a screenshot uploaded somewhere!

Ok, you're seeing frequency selective behaviour. This can happen for a
myriad of reasons, among these interference and multipath propagation.
You're excluding interference as a reason on an ISM band, so I presume
you're working with a direct cable between tx and rx or in an anechoic
chamber; thus multipath can't be the reason, either.

Greetings,
Marcus

On 07.08.2014 11:24, Marcus Müller wrote:
> FFT sink at the receiver or attached to the transmitter GRC?
> 
> Your GRCs don't work for me. With which version of GNU Radio were
> they built?
> 
> On 07.08.2014 11:10, chaitanya wrote:
>> Hi Martin, thanks for reply
>>> Wait, so it does work for more than one frequency? Where
>>> exactly does it not work?
>> Yes,it worked for more than one frequency .They are 2.45GHz
>> ,2.455GHz and 2.46GHz. It did not work(that means not reliable)
>> for 2.451GHz,2.452GHz,2.453GHz,2.454GHz and also between 2.456 to
>> 2.459GHz.
>> 
>> 
>>> Put in another way: The OFDM code is agnostic of the actual
>>> frequency. There is nothing in the OFDM code that will make it
>>> work better at one frequency than another.
>> Yeah, I also expected that. Thats why i posted this question.It
>> should work for all frequencies but its not working, I don't know
>> why.
>> 
>> Please if possible once try running those ofdm_sender.grc and 
>> ofdm_receiver.grc at  2.45Ghz and also at 2.452Ghz.And observe
>> the FFT sink.
>> 
>> chaitanya
>> 
>> 
>> 
>> 
>> -- View this message in context:
>> http://gnuradio.4.n7.nabble.com/OFDM-TRANSFER-and-RECEIVE-IN-GRC-tp49746p49841.html
>>
>> 
Sent from the GnuRadio mailing list archive at Nabble.com.
>> 
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> 
> 
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