UHD-Fairwaves/host/utils/uhd_cal_tx_dc_offset.cpp

//
// 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 <ctime>

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();

    //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);

    //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);

    //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) * wave_table_lookup(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
    usrp->set_rx_freq(usrp->get_tx_freq() - rx_offset);

    //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();
}

/***********************************************************************
 * 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_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 = \"\"]")
        ("rate", po::value<double>(&rate)->default_value(12.5e6), "RX and TX sample rate in Hz")
        ("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");

    //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_freq, 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_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);
        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);

                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("%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;
}