The 'verbosity' parameter may be used to increase or suppress output from
libbladeRF. The available log levels are, in order of decreasing
verbosity are:
verbose, debug, info, warning, critical, silent
The 'loopback' parameter may be used to put the bladeRF into one of the
supported loopback modes. The valid modes are listed below. Their
descriptions may be found in the libbladeRF documentation:
bb_txlpf_rxvga2, bb_txlpf_rxlpf bb_txvga1_rxvga2, bb_txvga1_rxlpf
rf_lna1, rf_lna2, rf_lna3