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Member
ErikL
Posts: 186
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Re: How to use NI USRP2920 to modulate and demodulate signal?

Hello -

 

My understanding of the VI's is that they are working as intended.  The VI's you are using demonstrate the concept of taking a random bit stream, modulating, transmitting, recieving, and demodulating.  This physical layer process seems to be working exactly as expected. You may also notice that the message is only genated once in the original example and is continuously output (meaning that there is no noticable 'beginning' or 'ending' to the continuously streaming constellation.

 

Secondly I understand that you are introducing your own set of bits, which contain meaningful data. (unlke the random bitstream used in the original example.)  For this type of data I recommend a more complex communications architecture using packets and error correction.  The following example video and code provide one possible alternative framework for accomplishing this task.

 

Building an over-the-air link:  http://zone.ni.com/wv/app/doc/p/id/wv-2757

 

Packet Based Link:  https://decibel.ni.com/content/docs/DOC-18801

 

Using this framework will require some effort to dig into the code, understand the program, and make the appropreate modifications to handle the structure of your data, but I believe it may provide you a more satisfactory result.

Member
phonglt03
Posts: 20
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Re: How to use NI USRP2920 to modulate and demodulate signal?

Hi,

 


ErikL wrote:

 

My understanding of the VI's is that they are working as intended.  The VI's you are using demonstrate the concept of taking a random bit stream, modulating, transmitting, recieving, and demodulating.  This physical layer process seems to be working exactly as expected. You may also notice that the message is only genated once in the original example and is continuously output (meaning that there is no noticable 'beginning' or 'ending' to the continuously streaming constellation.

 

 


I don't think so. I think the VI's can use to demonstrate modulation and demodulation functions.

I used R&S signal generator to create signal for NI USRP to demodulate but the result is the same.

 

Phong.

Member
PelinNJIT
Posts: 1
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Re: How to use NI USRP2920 to modulate and demodulate signal?

Phong, did you solve your problem yet? Could you please share with us the details if you did?

Thanks,

Pelin