uhd

//

// Copyright 2010 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 <http://www.gnu.org/licenses/>.

//

#include "usrp_cal_utils.hpp"

#include <uhd/utils/thread_priority.hpp>

#include <uhd/utils/safe_main.hpp>

#include <uhd/utils/paths.hpp>

#include <uhd/utils/algorithm.hpp>

#include <uhd/usrp/multi_usrp.hpp>

#include <boost/program_options.hpp>

#include <boost/format.hpp>

#include <boost/thread/thread.hpp>

#include <boost/math/special_functions/round.hpp>

#include <iostream>

#include <complex>

#include <cmath>

#include <ctime>

namespace po = boost::program_options;

/***********************************************************************

 * Transmit thread

 **********************************************************************/

static void tx_thread(uhd::usrp::multi_usrp::sptr usrp, const double tx_wave_ampl){

    uhd::set_thread_priority_safe();

    //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<std::complex<float> > buff(tx_stream->get_max_num_samps()*10);

    //fill buff and send until interrupted

    while (not boost::this_thread::interruption_requested()){

        for (size_t i = 0; i < buff.size(); i++){

            buff[i] = float(tx_wave_ampl);

        }

        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 rx_lo_freq, const double tx_offset){

    //tune the receiver with no cordic

    uhd::tune_request_t rx_tune_req(rx_lo_freq);

    rx_tune_req.dsp_freq_policy = uhd::tune_request_t::POLICY_MANUAL;

    rx_tune_req.dsp_freq = 0;

    usrp->set_rx_freq(rx_tune_req);

    //tune the transmitter with no cordic

    uhd::tune_request_t tx_tune_req(usrp->get_rx_freq() - tx_offset);

    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);

    //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_rx_freq();

}

/***********************************************************************

 * Data capture routine

 **********************************************************************/

static void capture_samples(uhd::usrp::multi_usrp::sptr usrp, uhd::rx_streamer::sptr rx_stream, std::vector<std::complex<float> > &buff){

    uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);

    stream_cmd.num_samps = buff.size();

    stream_cmd.stream_now = true;

    usrp->issue_stream_cmd(stream_cmd);

    uhd::rx_metadata_t md;

    const size_t num_rx_samps = rx_stream->recv(&buff.front(), buff.size(), md);

    //validate the received data

    if (md.error_code != uhd::rx_metadata_t::ERROR_CODE_NONE){

        throw std::runtime_error(str(boost::format(

            "Unexpected error code 0x%x"

        ) % md.error_code));

    }

    if (num_rx_samps != buff.size()){

        throw std::runtime_error("did not get all the samples requested");

    }

}

/***********************************************************************

 * Main

 **********************************************************************/

int UHD_SAFE_MAIN(int argc, char *argv[]){

    std::string args;

    double rate, tx_wave_ampl, tx_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 = \"\"]")

        ("rate", po::value<double>(&rate)->default_value(12.5e6), "RX and TX sample rate in Hz")

        ("tx_wave_ampl", po::value<double>(&tx_wave_ampl)->default_value(0.7), "Transmit wave amplitude in counts")

        ("tx_offset", po::value<double>(&tx_offset)->default_value(.9344e6), "TX LO offset from the RX 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 RX IQ Balance 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");

    //set optimum gain settings

    set_optimum_gain(usrp);

    //set the sample rates

    usrp->set_rx_rate(rate);

    usrp->set_tx_rate(rate);

    //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_ampl));

    //re-usable buffer for samples

    std::vector<std::complex<float> > buff(nsamps);

    //store the results here

    std::vector<result_t> results;

    if (not vm.count("freq_start")) freq_start = usrp->get_rx_freq_range().start() + 50e6;

    if (not vm.count("freq_stop")) freq_stop = usrp->get_rx_freq_range().stop() - 50e6;

    for (double rx_lo_i = freq_start; rx_lo_i <= freq_stop; rx_lo_i += freq_step){

        const double rx_lo = tune_rx_and_tx(usrp, rx_lo_i, tx_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_tone_freq = actual_tx_freq - actual_rx_freq;

        const double bb_imag_freq = -bb_tone_freq;

        //capture initial uncorrected value

        usrp->set_rx_iq_balance(std::polar<double>(1.0, 0.0));

        capture_samples(usrp, rx_stream, buff);

        const double initial_suppression = compute_tone_dbrms(buff, bb_tone_freq/actual_rx_rate) - compute_tone_dbrms(buff, bb_imag_freq/actual_rx_rate);

        //bounds and results from searching

        std::complex<double> best_correction;

        double phase_corr_start = -.3, phase_corr_stop = .3, phase_corr_step;

        double ampl_corr_start = -.3, ampl_corr_stop = .3, ampl_corr_step;

        double best_suppression = 0, best_phase_corr = 0, best_ampl_corr = 0;

        for (size_t i = 0; i < num_search_iters; i++){

            phase_corr_step = (phase_corr_stop - phase_corr_start)/(num_search_steps-1);

            ampl_corr_step = (ampl_corr_stop - ampl_corr_start)/(num_search_steps-1);

            for (double phase_corr = phase_corr_start; phase_corr <= phase_corr_stop + phase_corr_step/2; phase_corr += phase_corr_step){

            for (double ampl_corr = ampl_corr_start; ampl_corr <= ampl_corr_stop + ampl_corr_step/2; ampl_corr += ampl_corr_step){

                const std::complex<double> correction = std::polar(ampl_corr+1, phase_corr*tau);

                usrp->set_rx_iq_balance(correction);

                //receive some samples

                capture_samples(usrp, rx_stream, buff);

                const double tone_dbrms = compute_tone_dbrms(buff, bb_tone_freq/actual_rx_rate);

                const double imag_dbrms = compute_tone_dbrms(buff, bb_imag_freq/actual_rx_rate);

                const double suppression = tone_dbrms - imag_dbrms;

                if (suppression > best_suppression){

                    best_correction = correction;

                    best_suppression = suppression;

                    best_phase_corr = phase_corr;

                    best_ampl_corr = ampl_corr;

                }

            }}

            //std::cout << "best_phase_corr " << best_phase_corr << std::endl;

            //std::cout << "best_ampl_corr " << best_ampl_corr << std::endl;

            //std::cout << "best_suppression " << best_suppression << std::endl;

            phase_corr_start = best_phase_corr - phase_corr_step;

            phase_corr_stop = best_phase_corr + phase_corr_step;

            ampl_corr_start = best_ampl_corr - ampl_corr_step;

            ampl_corr_stop = best_ampl_corr + ampl_corr_step;

        }

        if (best_suppression > 30){ //most likely valid, keep result

            result_t result;

            result.freq = rx_lo;

            result.real_corr = best_correction.real();

            result.imag_corr = best_correction.imag();

            result.best = best_suppression;

            result.delta = best_suppression - initial_suppression;

            results.push_back(result);

            if (vm.count("verbose")){

                std::cout << boost::format("%f MHz: best suppression %fdB, corrected %fdB") % (rx_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, "RX", "rx", "iq");

    return 0;

}