//
// 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;
}