/***********************************************************************
* Setup function
**********************************************************************/
static uhd::usrp::multi_usrp::sptr setup_usrp_for_cal(std::string &args, std::string &subdev, std::string &serial)
{
std::cout << std::endl;
std::cout << boost::format("Creating the usrp device with: %s...") % args << std::endl;
uhd::usrp::multi_usrp::sptr usrp = uhd::usrp::multi_usrp::make(args);
// Configure subdev
if (!subdev.empty())
{
usrp->set_tx_subdev_spec(subdev);
usrp->set_rx_subdev_spec(subdev);
}
std::cout << "Running calibration for " << usrp->get_tx_subdev_name(0);
serial = get_serial(usrp, "tx");
std::cout << "Daughterboard serial: " << serial;
//set the antennas to cal
if (not uhd::has(usrp->get_rx_antennas(), "CAL") or not uhd::has(usrp->get_tx_antennas(), "CAL"))
throw std::runtime_error("This board does not have the CAL antenna option, cannot self-calibrate.");
usrp->set_rx_antenna("CAL");
usrp->set_tx_antenna("CAL");
//fail if daughterboard has no serial
check_for_empty_serial(usrp);
//set optimum defaults
set_optimum_defaults(usrp);
return usrp;
}
/***********************************************************************
* Main
**********************************************************************/
int UHD_SAFE_MAIN(int argc, char *argv[]){
std::string args;
double tx_wave_freq, tx_wave_ampl, rx_offset;
double freq_start, freq_stop, freq_step;
size_t nsamps;
po::options_description desc("Allowed options");
desc.add_options()
("help", "help message")
("verbose", "enable some verbose")
("args", po::value<std::string>(&args)->default_value(""), "device address args [default = \"\"]")
("tx_wave_freq", po::value<double>(&tx_wave_freq)->default_value(507.123e3), "Transmit wave frequency in Hz")
("tx_wave_ampl", po::value<double>(&tx_wave_ampl)->default_value(0.7), "Transmit wave amplitude in counts")
("rx_offset", po::value<double>(&rx_offset)->default_value(.9344e6), "RX LO offset from the TX LO in Hz")
("freq_start", po::value<double>(&freq_start), "Frequency start in Hz (do not specify for default)")
("freq_stop", po::value<double>(&freq_stop), "Frequency stop in Hz (do not specify for default)")
("freq_step", po::value<double>(&freq_step)->default_value(default_freq_step), "Step size for LO sweep in Hz")
("nsamps", po::value<size_t>(&nsamps)->default_value(default_num_samps), "Samples per data capture")
;
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
po::notify(vm);
//print the help message
if (vm.count("help")){
std::cout << boost::format("USRP Generate TX DC Offset Calibration Table %s") % desc << std::endl;
std::cout <<
"This application measures leakage between RX and TX on an XCVR daughterboard to self-calibrate.\n"
<< std::endl;
return ~0;
}
//create a usrp device
std::cout << std::endl;
std::cout << boost::format("Creating the usrp device with: %s...") % args << std::endl;
uhd::usrp::multi_usrp::sptr usrp = uhd::usrp::multi_usrp::make(args);
//set the antennas to cal
if (not uhd::has(usrp->get_rx_antennas(), "CAL") or not uhd::has(usrp->get_tx_antennas(), "CAL")){
throw std::runtime_error("This board does not have the CAL antenna option, cannot self-calibrate.");
}
usrp->set_rx_antenna("CAL");
usrp->set_tx_antenna("CAL");
//fail if daughterboard has no serial
check_for_empty_serial(usrp, "TX", "tx", args);
//set optimum defaults
set_optimum_defaults(usrp);
//create a receive streamer
uhd::stream_args_t stream_args("fc32"); //complex floats
uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
//create a transmitter thread
boost::thread_group threads;
threads.create_thread(boost::bind(&tx_thread, usrp, tx_wave_freq, tx_wave_ampl));
//re-usable buffer for samples
std::vector<samp_type> buff;
//store the results here
std::vector<result_t> results;
if (not vm.count("freq_start")) freq_start = usrp->get_tx_freq_range().start() + 50e6;
if (not vm.count("freq_stop")) freq_stop = usrp->get_tx_freq_range().stop() - 50e6;
for (double tx_lo_i = freq_start; tx_lo_i <= freq_stop; tx_lo_i += freq_step){
const double tx_lo = tune_rx_and_tx(usrp, tx_lo_i, rx_offset);
//frequency constants for this tune event
const double actual_rx_rate = usrp->get_rx_rate();
const double actual_tx_freq = usrp->get_tx_freq();
const double actual_rx_freq = usrp->get_rx_freq();
const double bb_dc_freq = actual_tx_freq - actual_rx_freq;
//capture initial uncorrected value
usrp->set_tx_dc_offset(std::complex<double>(0, 0));
capture_samples(usrp, rx_stream, buff, nsamps);
const double initial_dc_dbrms = compute_tone_dbrms(buff, bb_dc_freq/actual_rx_rate);
//bounds and results from searching
double dc_i_start = -.01, dc_i_stop = .01, dc_i_step;
double dc_q_start = -.01, dc_q_stop = .01, dc_q_step;
double lowest_offset = 0, best_dc_i = 0, best_dc_q = 0;
for (size_t i = 0; i < num_search_iters; i++){
dc_i_step = (dc_i_stop - dc_i_start)/(num_search_steps-1);
dc_q_step = (dc_q_stop - dc_q_start)/(num_search_steps-1);
for (double dc_i = dc_i_start; dc_i <= dc_i_stop + dc_i_step/2; dc_i += dc_i_step){
for (double dc_q = dc_q_start; dc_q <= dc_q_stop + dc_q_step/2; dc_q += dc_q_step){
const std::complex<double> correction(dc_i, dc_q);
usrp->set_tx_dc_offset(correction);
//receive some samples
capture_samples(usrp, rx_stream, buff, nsamps);
const double dc_dbrms = compute_tone_dbrms(buff, bb_dc_freq/actual_rx_rate);
if (dc_dbrms < lowest_offset){
lowest_offset = dc_dbrms;
best_dc_i = dc_i;
best_dc_q = dc_q;
}
}}
//std::cout << "best_dc_i " << best_dc_i << std::endl;
//std::cout << "best_dc_q " << best_dc_q << std::endl;
//std::cout << "lowest_offset " << lowest_offset << std::endl;
dc_i_start = best_dc_i - dc_i_step;
dc_i_stop = best_dc_i + dc_i_step;
dc_q_start = best_dc_q - dc_q_step;
dc_q_stop = best_dc_q + dc_q_step;
}
if (lowest_offset < initial_dc_dbrms){ //most likely valid, keep result
result_t result;
result.freq = tx_lo;
result.real_corr = best_dc_i;
result.imag_corr = best_dc_q;
result.best = lowest_offset;
result.delta = initial_dc_dbrms - lowest_offset;
results.push_back(result);
if (vm.count("verbose")){
std::cout << boost::format("TX DC: %f MHz: lowest offset %f dB, corrected %f dB") % (tx_lo/1e6) % result.best % result.delta << std::endl;
}
else std::cout << "." << std::flush;
}
}
std::cout << std::endl;
//stop the transmitter
threads.interrupt_all();
threads.join_all();
store_results(usrp, results, "TX", "tx", "dc");
return 0;
}
