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https://github.com/saymrwulf/uhd.git
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66 lines
2.4 KiB
C++
66 lines
2.4 KiB
C++
//
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// Copyright 2010-2012,2014 Ettus Research LLC
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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#include <string>
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#include <cmath>
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#include <complex>
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#include <vector>
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#include <stdexcept>
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static const size_t wave_table_len = 8192;
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class wave_table_class{
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public:
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wave_table_class(const std::string &wave_type, const float ampl):
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_wave_table(wave_table_len)
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{
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//compute real wave table with 1.0 amplitude
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std::vector<double> real_wave_table(wave_table_len);
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if (wave_type == "CONST"){
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for (size_t i = 0; i < wave_table_len; i++)
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real_wave_table[i] = 1.0;
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}
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else if (wave_type == "SQUARE"){
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for (size_t i = 0; i < wave_table_len; i++)
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real_wave_table[i] = (i < wave_table_len/2)? 0.0 : 1.0;
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}
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else if (wave_type == "RAMP"){
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for (size_t i = 0; i < wave_table_len; i++)
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real_wave_table[i] = 2.0*i/(wave_table_len-1) - 1.0;
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}
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else if (wave_type == "SINE"){
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static const double tau = 2*std::acos(-1.0);
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for (size_t i = 0; i < wave_table_len; i++)
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real_wave_table[i] = std::sin((tau*i)/wave_table_len);
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}
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else throw std::runtime_error("unknown waveform type: " + wave_type);
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//compute i and q pairs with 90% offset and scale to amplitude
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for (size_t i = 0; i < wave_table_len; i++){
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const size_t q = (i+(3*wave_table_len)/4)%wave_table_len;
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_wave_table[i] = std::complex<float>(ampl*real_wave_table[i], ampl*real_wave_table[q]);
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}
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}
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inline std::complex<float> operator()(const size_t index) const{
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return _wave_table[index % wave_table_len];
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}
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private:
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std::vector<std::complex<float> > _wave_table;
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};
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