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//
// 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 <uhd/usrp/tune_helper.hpp>
#include <uhd/utils/algorithm.hpp>
#include <uhd/usrp/subdev_props.hpp>
#include <cmath>
using namespace uhd;
using namespace uhd::usrp;
/***********************************************************************
* Tune Helper Function
**********************************************************************/
static tune_result_t tune_xx_subdev_and_dxc(
bool is_tx,
wax::obj subdev, wax::obj dxc,
double target_freq, double lo_offset
){
wax::obj subdev_freq_proxy = subdev[SUBDEV_PROP_FREQ];
bool subdev_quadrature = subdev[SUBDEV_PROP_QUADRATURE].as<bool>();
bool subdev_spectrum_inverted = subdev[SUBDEV_PROP_SPECTRUM_INVERTED].as<bool>();
wax::obj dxc_freq_proxy = dxc[std::string("freq")];
double dxc_sample_rate = dxc[std::string("if_rate")].as<double>();
// Ask the d'board to tune as closely as it can to target_freq+lo_offset
double target_inter_freq = target_freq + lo_offset;
subdev_freq_proxy = target_inter_freq;
double actual_inter_freq = subdev_freq_proxy.as<double>();
// Calculate the DDC setting that will downconvert the baseband from the
// daughterboard to our target frequency.
double delta_freq = target_freq - actual_inter_freq;
double delta_sign = std::signum(delta_freq);
delta_freq *= delta_sign;
delta_freq = std::fmod(delta_freq, dxc_sample_rate);
bool inverted = delta_freq > dxc_sample_rate/2.0;
double target_dxc_freq = inverted? (delta_freq - dxc_sample_rate) : (-delta_freq);
target_dxc_freq *= delta_sign;
// If the spectrum is inverted, and the daughterboard doesn't do
// quadrature downconversion, we can fix the inversion by flipping the
// sign of the dxc_freq... (This only happens using the basic_rx board)
if (subdev_spectrum_inverted){
inverted = not inverted;
}
if (inverted and not subdev_quadrature){
target_dxc_freq *= -1.0;
inverted = not inverted;
}
// down conversion versus up conversion, fight!
// your mother is ugly and your going down...
target_dxc_freq *= (is_tx)? -1.0 : +1.0;
dxc_freq_proxy = target_dxc_freq;
double actual_dxc_freq = dxc_freq_proxy.as<double>();
//return some kind of tune result tuple/struct
tune_result_t tune_result;
tune_result.target_inter_freq = target_inter_freq;
tune_result.actual_inter_freq = actual_inter_freq;
tune_result.target_dxc_freq = target_dxc_freq;
tune_result.actual_dxc_freq = actual_dxc_freq;
tune_result.spectrum_inverted = inverted;
return tune_result;
}
/***********************************************************************
* RX Tune
**********************************************************************/
tune_result_t uhd::usrp::tune_rx_subdev_and_ddc(
wax::obj subdev, wax::obj ddc,
double target_freq, double lo_offset
){
bool is_tx = false;
return tune_xx_subdev_and_dxc(is_tx, subdev, ddc, target_freq, lo_offset);
}
tune_result_t uhd::usrp::tune_rx_subdev_and_ddc(
wax::obj subdev, wax::obj ddc,
double target_freq
){
double lo_offset = 0.0;
//if the local oscillator will be in the passband, use an offset
if (subdev[SUBDEV_PROP_LO_INTERFERES].as<bool>()){
lo_offset = 2.0*ddc[std::string("bb_rate")].as<double>();
}
return tune_rx_subdev_and_ddc(subdev, ddc, target_freq, lo_offset);
}
/***********************************************************************
* TX Tune
**********************************************************************/
tune_result_t uhd::usrp::tune_tx_subdev_and_duc(
wax::obj subdev, wax::obj duc,
double target_freq, double lo_offset
){
bool is_tx = true;
return tune_xx_subdev_and_dxc(is_tx, subdev, duc, target_freq, lo_offset);
}
tune_result_t uhd::usrp::tune_tx_subdev_and_duc(
wax::obj subdev, wax::obj duc,
double target_freq
){
double lo_offset = 0.0;
//if the local oscillator will be in the passband, use an offset
if (subdev[SUBDEV_PROP_LO_INTERFERES].as<bool>()){
lo_offset = 2.0*duc[std::string("bb_rate")].as<double>();
}
return tune_tx_subdev_and_duc(subdev, duc, target_freq, lo_offset);
}
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