How to transmit and receive using a single attena with USRP

[0711]

Hi everyone,

     I want to make a RFID reader with USRP. I want to send an activate signal to the RFID tag first and then receive and decode the signal reflected by the tag. As I know, there are two RF interface on the daughterboard of USRP, I can transmit and receive the signals using two attenas. But how can I transmit the activation signal and receive the reflection signal using one attena?

    Thanks in advance

[Sarah_Y · Accepted solution]

Hi 0711,

If you use the TX/RX port, you should be able to transmit and receive using the same antenna.  But it does require more setup in the code.  You should have at least 2 loops in your code--one running an RX session and another one running a TX session.  You can use the "End of Data?" option on the niUSRP Write Tx Data.vi as a way to send out your data without having to start and stop the session each time.  In order to get the data flow between the RX session and TX session, I used queues.

I have been working to put together an example that shows the basic architecture that is needed to run an application like this.  This example isn't polished or finished, but I have seen some requests for how to do this so I am going to post it to give you are starting point.  Please note that this code still has issues that need to be debugged and addressed.  It is simply meant to show how to use the end of data? option to enable transmitting a burst while receiving data on the same antenna.  If you set the antennas to TX1 and RX2 and use a loopback configuration, you can also use this code with one USRP.  Hope this helps, and please post questions.

[0711]

Thank you very much Sarah Y. I will learn your example.

[edwardfu]

yo dude!!could you send this file again in 2009 version??thanks a lot!!