// // Copyright 2010,2012,2014 Ettus Research LLC // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see . // #include "usrp_cal_utils.hpp" #include #include #include #include #include #include #include #include #include #include #include #include namespace po = boost::program_options; /*********************************************************************** * Transmit thread **********************************************************************/ static void tx_thread(uhd::usrp::multi_usrp::sptr usrp, const double tx_wave_freq, const double tx_wave_ampl) { uhd::set_thread_priority_safe(); // set max TX gain usrp->set_tx_gain(usrp->get_tx_gain_range().stop()); //create a transmit streamer uhd::stream_args_t stream_args("fc32"); //complex floats uhd::tx_streamer::sptr tx_stream = usrp->get_tx_stream(stream_args); //setup variables and allocate buffer uhd::tx_metadata_t md; md.has_time_spec = false; std::vector buff(tx_stream->get_max_num_samps()*10); //values for the wave table lookup size_t index = 0; const double tx_rate = usrp->get_tx_rate(); const size_t step = boost::math::iround(wave_table_len * tx_wave_freq / tx_rate); wave_table table(tx_wave_ampl); //fill buff and send until interrupted while (not boost::this_thread::interruption_requested()) { for (size_t i = 0; i < buff.size(); i++) buff[i] = table(index += step); tx_stream->send(&buff.front(), buff.size(), md); } //send a mini EOB packet md.end_of_burst = true; tx_stream->send("", 0, md); } /*********************************************************************** * Tune RX and TX routine **********************************************************************/ static double tune_rx_and_tx(uhd::usrp::multi_usrp::sptr usrp, const double tx_lo_freq, const double rx_offset) { //tune the transmitter with no cordic uhd::tune_request_t tx_tune_req(tx_lo_freq); tx_tune_req.dsp_freq_policy = uhd::tune_request_t::POLICY_MANUAL; tx_tune_req.dsp_freq = 0; usrp->set_tx_freq(tx_tune_req); //tune the receiver double rx_freq = usrp->get_tx_freq() - rx_offset; double min_fe_rx_freq = usrp->get_fe_rx_freq_range().start(); double max_fe_rx_freq = usrp->get_fe_rx_freq_range().stop(); uhd::tune_request_t rx_tune_req(rx_freq); rx_tune_req.dsp_freq_policy = uhd::tune_request_t::POLICY_MANUAL; rx_tune_req.dsp_freq = 0; if (rx_freq < min_fe_rx_freq) rx_tune_req.dsp_freq = rx_freq - min_fe_rx_freq; else if (rx_freq > max_fe_rx_freq) rx_tune_req.dsp_freq = rx_freq - max_fe_rx_freq; usrp->set_rx_freq(rx_tune_req); //wait for the LOs to become locked boost::this_thread::sleep(boost::posix_time::milliseconds(50)); boost::system_time start = boost::get_system_time(); while (not usrp->get_tx_sensor("lo_locked").to_bool() or not usrp->get_rx_sensor("lo_locked").to_bool()) { if (boost::get_system_time() > start + boost::posix_time::milliseconds(100)) throw std::runtime_error("timed out waiting for TX and/or RX LO to lock"); } return usrp->get_tx_freq(); } /*********************************************************************** * Main **********************************************************************/ int UHD_SAFE_MAIN(int argc, char *argv[]) { std::string args, subdev, serial; double tx_wave_freq, tx_wave_ampl, rx_offset; double freq_start, freq_stop, freq_step; size_t nsamps; double precision; po::options_description desc("Allowed options"); desc.add_options() ("help", "help message") ("verbose", "enable some verbose") ("args", po::value(&args)->default_value(""), "device address args [default = \"\"]") ("subdev", po::value(&subdev), "Subdevice specification (default: first subdevice, often 'A')") ("tx_wave_freq", po::value(&tx_wave_freq)->default_value(507.123e3), "Transmit wave frequency in Hz") ("tx_wave_ampl", po::value(&tx_wave_ampl)->default_value(0.7), "Transmit wave amplitude") ("rx_offset", po::value(&rx_offset)->default_value(.9344e6), "RX LO offset from the TX LO in Hz") ("freq_start", po::value(&freq_start), "Frequency start in Hz (do not specify for default)") ("freq_stop", po::value(&freq_stop), "Frequency stop in Hz (do not specify for default)") ("freq_step", po::value(&freq_step)->default_value(default_freq_step), "Step size for LO sweep in Hz") ("nsamps", po::value(&nsamps), "Samples per data capture") ("precision", po::value(&precision)->default_value(default_precision), "Correction precision (default=0.0001)") ; 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 a transceiver daughterboard to self-calibrate.\n" "Note: Not all daughterboards support this feature. Refer to the UHD manual for details.\n" << std::endl; return EXIT_FAILURE; } // Create a USRP device uhd::usrp::multi_usrp::sptr usrp = setup_usrp_for_cal(args, subdev, serial); if (not vm.count("nsamps")) nsamps = size_t(usrp->get_rx_rate() / default_fft_bin_size); //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 buff; //store the results here std::vector results; if (not vm.count("freq_start")) freq_start = usrp->get_fe_tx_freq_range().start(); if (not vm.count("freq_stop")) freq_stop = usrp->get_fe_tx_freq_range().stop(); //check start and stop frequencies if (freq_start < usrp->get_fe_tx_freq_range().start()) { std::cerr << "freq_start must be " << usrp->get_fe_tx_freq_range().start() << " or greater for this daughter board" << std::endl; return EXIT_FAILURE; } if (freq_stop > usrp->get_fe_tx_freq_range().stop()) { std::cerr << "freq_stop must be " << usrp->get_fe_tx_freq_range().stop() << " or less for this daughter board" << std::endl; return EXIT_FAILURE; } //check rx_offset double min_rx_offset = usrp->get_rx_freq_range().start() - usrp->get_fe_tx_freq_range().start(); double max_rx_offset = usrp->get_rx_freq_range().stop() - usrp->get_fe_tx_freq_range().stop(); if (rx_offset < min_rx_offset or rx_offset > max_rx_offset) { std::cerr << "rx_offset must be between " << min_rx_offset << " and " << max_rx_offset << " for this daughter board" << std::endl; return EXIT_FAILURE; } std::cout << boost::format("Calibration frequency range: %d MHz -> %d MHz") % (freq_start/1e6) % (freq_stop/1e6) << std::endl; //set RX gain usrp->set_rx_gain(0); 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; //reset TX DC offset usrp->set_tx_dc_offset(std::complex(0, 0)); //capture initial uncorrected value 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 i_corr_start = -1.0; double i_corr_stop = 1.0; double i_corr_step = (i_corr_stop - i_corr_start)/(num_search_steps+1); double q_corr_start = -1.0; double q_corr_stop = 1.0; double q_corr_step= (q_corr_stop - q_corr_start)/(num_search_steps+1); double best_dc_dbrms = initial_dc_dbrms; double best_i_corr = 0; double best_q_corr = 0; while (i_corr_step >= precision or q_corr_step >= precision) { for (double i_corr = i_corr_start + i_corr_step; i_corr <= i_corr_stop - i_corr_step; i_corr += i_corr_step) { for (double q_corr = q_corr_start + q_corr_step; q_corr <= q_corr_stop - q_corr_step; q_corr += q_corr_step) { const std::complex correction(i_corr, q_corr); 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 < best_dc_dbrms) { best_dc_dbrms = dc_dbrms; best_i_corr = i_corr; best_q_corr = q_corr; } } } i_corr_start = best_i_corr - i_corr_step; i_corr_stop = best_i_corr + i_corr_step; i_corr_step = (i_corr_stop - i_corr_start)/(num_search_steps+1); q_corr_start = best_q_corr - q_corr_step; q_corr_stop = best_q_corr + q_corr_step; q_corr_step = (q_corr_stop - q_corr_start)/(num_search_steps+1); } if (best_dc_dbrms < initial_dc_dbrms) //keep result { result_t result; result.freq = tx_lo; result.real_corr = best_i_corr; result.imag_corr = best_q_corr; result.best = best_dc_dbrms; result.delta = initial_dc_dbrms - best_dc_dbrms; 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(); boost::this_thread::sleep(boost::posix_time::milliseconds(500)); //wait for threads to finish threads.join_all(); store_results(results, "TX", "tx", "dc", serial); return EXIT_SUCCESS; }