[USRP-users] signal level oscilation at the beginning of burst

Julian Arnold julian at elitecoding.org
Thu Jul 27 07:58:50 EDT 2017


Hey Jie,

I'm only guessing here but I think what you  are seeing are the effects
of using a real-world system with non-ideal frequency response with a
signal that has very high frequency content (due to short rise and fall
times of the pulses).
Attached you see a simulation of a pulse source with very short rise and
fall times connected to an LC series circuit.
The blue trace is showing the output of the pulse source and the green
trace is showing the signal after the inductor.
If you were to apply some sort of pulse-shaping to your signal, as you
would normally do in a communication system, you probably would not see
those oscillations any more.

Cheers,
Julian

On 07/24/2017 10:36 PM, Jie Song via USRP-users wrote:
>
> Hi,
>
>  
>
> I am modifying the “txrx_loopback_to_file” example on B210 to make the
> TX signal burst.  The TX and RX gains are configured manually at fixed
> value, but the received signal level has some oscilation the at the
> beginning of each burst.  Could anybody explain why this happens
> please?  The figure below shows the problem:
>
>  
>
> Thanks a lot,
>
> Jie
>
>  
>
>  
>
>  
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

-- 
Julian Arnold, M.Sc.

Institute for Networked Systems
RWTH Aachen University

Kackertstrasse 9
52072 Aachen
Germany

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