[USRP-users] looping the USRP2 in Simulink

Sacha Vrazic vrazic at free-impulse.com
Mon Nov 29 04:39:02 EST 2010


Hello everyone!

I am using one USRP2 board with LFRX and LFTX daughter boards inside.
I want to check if the symbols I sent are well received. For that purpose I
made 2 simulink models (one for transmitter and one for receiver), I use a
QPSK modulation and a carrier frequency of 2 MHz.
I also connect the Tx out to the Rx In with a coaxial cable.

Unfortunately I cannot get the correct at the receiver the symbols I
transmitted. When I observe the receive constellation (under simulink), it
looks like there a phase problem or fading. But I do not understand because
in that case the channel is reduced to a 20 cm coaxial cable.
So I come with several questions:

* Is the Rx output baseband or at an Intermediate frequency?
* Is the power of the signal enough at the entrance of the receiver when
looping?
* Could it be a phase problem between transmitter and receiver?

If you have any idea or suggestions how to solve this issue, I would be
grateful.

Thank you!

Sacha
 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20101129/43d61c8e/attachment-0002.html>


More information about the USRP-users mailing list