[Discuss-gnuradio] Simultaneous transmit/receive not using antennas?

[Kimminau Jr., Leo F.]

Using USRP and FLEX900 daughterboards:

 

During simultaneous transmit/receive it seems the ‘receive’ data sent to the computer, is just a copy of the ‘transmit’ data sent to the FPGA, and is not actually being sampled from the receive antenna, since disconnecting either the transmit/receive antenna doesn’t affect the signal shown in the usrp_oscope display.

 

I opened two terminal windows and ran usrp_oscope in one and usrp_siggen in another, and specified either:

-          Side A and Side B with two daughterboards in one USRP, or

-          USRP 0 and USRP 1 with two USRPs connected to one computer.

 

I also used GRC to write a flow graph to access the TX/RX and RX2 ports on one daughterboard.

 

When I connect two USRPs to different computers and then disconnect either antenna, the signal shown in the usrp_oscope display of the ‘receive’ data, i.e., reduces amplitude from +/- 16KHz to +/- 800Hz.

 

This what I’d expect from simultaneous transmit/receive using one USRP or computer, is that expected when using usrp_siggen and usrp_oscope?

 

 

Leo Kimminau