Forum: GNU Radio No Digital Modulation Working

Posted by Ahmed Zaheer (Guest)
on 2012-10-23 00:04
Attachment: GMSK_Trans_Receive.png (264 KB)
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Hi all,
I was trying to make a transceiver working on any digital modulation. I 
have tried GMSK, PSK, QPSK, QAM and other blocks available in gnuradio 
companion. But non of them works. All of them works in loop back manner 
but when ever I try to transmit and receive on air it simply doesn't 
work. In the attached file I am using GMSK while transmitting a video 
file. I have also tried audio file, and even a simple sine wave but all 
in vain. I am using USRP N210 with SBX daugherboard with VERT 2450 
antenna. All of the equipment works as I was succeeded in transmitting 
my voice while doing frequency modulation. If anybody can tell me about 
any mistake while seeing the attached file or provide me with any 
transceiver using any digital modulation which should work on latest 
gnuradio with USRP N210 that would really be a great help.
I really appreciate your help.
Regards.
Ahmed.
Posted by sumitstop (Guest)
on 2012-10-23 06:19
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Did you compensate for the LO offset between Tx and Rx ?



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Posted by Ahmed Zaheer (Guest)
on 2012-10-23 15:08
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Can you give me any clue how to do that?
Regards.


________________________________
 From: sumitstop <sumit.kumar@research.iiit.ac.in>
To: Discuss-gnuradio@gnu.org
Sent: Monday, October 22, 2012 9:18 PM
Subject: Re: [Discuss-gnuradio] No Digital Modulation Working

Did you compensate for the LO offset between Tx and Rx ?



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Posted by Josh Blum (Guest)
on 2012-10-23 17:25
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On 10/22/2012 03:03 PM, Ahmed Zaheer wrote:
> attached file or provide me with any transceiver using any digital
> modulation which should work on latest gnuradio with USRP N210 that
> would really be a great help. I really appreciate your help.
> Regards. Ahmed.
>

One issue is that all the TX samples are clipping.
You actually want a transmit amplitude < 1.0

-josh

PS this project may also interest you:
https://github.com/buoyboy/pre-cog
Posted by sumitstop (Guest)
on 2012-10-23 20:00
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Have a look on this
http://sumitgnuradio.blogspot.in/2012/10/problem-o...




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