Re: [Discuss-gnuradio] OFDM Transmiter and receiver by using USRP1

[waqasme]

Hi Marcus,

As i mentioned the flow graph signal blocks i have used in gnu radio
companion from that i am getting this out put on FFT sink in GNU radio
companion simulation flowgraph which is similar like this 






and i have used RF cable to connect from USRP1 TX board to the spectrum
analyser RF out put and i am getting the output like this






In spectrum analyser iam getting noise and only 1 peak in the middle which
does not look like ofdm signal.
I insert both the images above so you can have a look and please let me know
what could be the problem.
I have used 2.4GHz frequency and i am using USRP1 board . i hope the above
too diagrams help you to understand my problem.

Thanks and Regards,

Marcus D. Leech wrote:
> 
> On 10/16/2011 12:29 PM, waqasme wrote:
>> Hello all,
>> I am trying to transmitt and recieve OFDM signal Via USRP1 board. I made
>> basic simulation in GNU radio a signal source block and then interleave
>> and
>> then OFDM modulator and then channel model block then usrp1 sink and fft
>> sink to see the output..In FFT sink at the end it shows proper square
>> like
>> OFDM signal but on the other hand in spectrum analyser it shows only one
>> peak sine wav signal not OFDM. I tried to play with the setiings but
>> couldnot get the desired ofdm signal output. This is just tranmitter
>> setup
>> and i attched with spectrum anlyzer but i dinot get OFDM signal . iam
>> only
>> getting simple sine wave in the spectrum analyser. I tried with simple
>> random sourse block and then DQPSK modulator and Usrp sink then it worked
>> it
>> shows sine wave signal in out put at spectrum analyser.Please any body
>> know
>> how to fix this problem or any solution ??? For reciever part i will use
>> the
>> same block in reverse order with ofdm demodulator..  All suggestions are
>> appriciated.
>> Looking forward to it...
>>
>> Thanks in advance..
>> waq.
> More specificity is usually required to allow people to help you.  
> Posting your (GRC-produced) flow-graph would help.
> 
>  From your description it's hard for anyone to help you.
> 
> 
> 
> -- 
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
> 
> 
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> Discuss-gnuradio mailing list
> address@hidden
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> 
> 
http://old.nabble.com/file/p32663266/fft%2Bofdm_spectrum.jpg 
http://old.nabble.com/file/p32663266/fft%2Bofdm_spectrum.jpg 
http://old.nabble.com/file/p32663266/fft%2Bofdm_spectrum.jpg
fft+ofdm_spectrum.jpg  http://old.nabble.com/file/p32663266/ofdm_spec.gif 
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