Calibration Error on USRP N320 When Using SSH

Issue Details

When running the uhd_cal_rx_iq_balance utility on a USRP N320 over SSH, the following error occurs:

[WARNING] TX error detected! Repeating current iteration
...
terminate called without an active exception
Aborted

This issue arises during the calibration sweep and results in the process terminating unexpectedly. 

Solution

The USRP N320 is equipped with a Zynq-7100 SoC, which has limited computational resources. Running calibration utilities directly on the device—especially over SSH—can overwhelm the system, particularly when calibration and data streaming occur simultaneously.

To resolve this issue:

1. Use a Host PC to perform the calibration instead of running it directly on the USRP.
2. Connect the USRP to the host via SFP+:
   Option 1: Use a 10Gbps SFP+ cable connected to a PCIe NIC on your PC.
   Option 2: Use a 10Gbps-to-1Gbps adapter and a 1Gbps Ethernet cable.
   Verify FPGA image compatibility with your connection type (10Gbps or 1Gbps).
3. Run the calibration utility from the host: $uhd_cal_rx_iq_balance --verbose --args="addr=192.168.10.2"

Note: Ensure that the host PC has UHD installed and is compatible with the USRP’s firmware.