[USRP-users] txrx_loopback_to_file test

Raul Casas rcasas at cadence.com
Mon Oct 20 15:01:24 EDT 2014


I would like to run a basic TX/RX loopback test on a B200 using the baseline utility function.  I connect an SMA cable with 30dB inline attenuator from RF A: TX/RX to RF A: RX2 and run the command below.  The resulting sample stream does not look correct  - the samples are low in amplitude and look quantized.  I am concerned the antenna and device parameters (tx-and, rx-ant, tx-subdev, rx-subdev, tx-channels, rx-channels) are not setup properly.  Can someone please tell me if and how those need to be configured and if there is some documentation available describing this for the B200?

Thanks for the help.
Raul.

txrx_loopback_to_file.exe -tx-rate 2e6 -rx-rate 2e6 -tx-freq 1e9 -wave-type SINE -wave-freq 100000 -rx_gain 20

Win32; Microsoft Visual C++ version 10.0; Boost_105400; UHD_003.007.002-release


Creating the transmit usrp device with: ...
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 32.000000 MHz
-- Actually got clock rate 32.000000 MHz
-- Performing timer loopback test... pass

Creating the receive usrp device with: ...
Using Device: Single USRP:
  Device: B-Series Device
  Mboard 0: B200
  RX Channel: 0
    RX DSP: 0
    RX Dboard: A
    RX Subdev: FE-RX2
  TX Channel: 0
    TX DSP: 0
    TX Dboard: A
    TX Subdev: FE-TX2

Using Device: Single USRP:
  Device: B-Series Device
  Mboard 0: B200
  RX Channel: 0
    RX DSP: 0
    RX Dboard: A
    RX Subdev: FE-RX2
  TX Channel: 0
    TX DSP: 0
    TX Dboard: A
    TX Subdev: FE-TX2

Setting TX Rate: 2.000000 Msps...
Actual TX Rate: 2.000000 Msps...

Setting RX Rate: 2.000000 Msps...
Actual RX Rate: 2.000000 Msps...

Setting TX Freq: 1000.000000 MHz...
Actual TX Freq: 1000.000000 MHz...

Setting RX Freq: 1000.000000 MHz...
Actual RX Freq: 1000.000000 MHz...

Press Ctrl + C to stop streaming...
Setting device timestamp to 0...

Done!
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