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119 lines
3.5 KiB
C++
119 lines
3.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
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// written by Christian Daniel //
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// Copyright (C) 2016-2019 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
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// Copyright (C) 2020 Kacper Michajłow <kasper93@gmail.com> //
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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 as 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 V3 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 <QtGlobal>
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#include <cstdio>
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#include <cmath>
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#include "dsp/nco.h"
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Real NCO::m_table[NCO::TableSize];
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bool NCO::m_tableInitialized = false;
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void NCO::initTable()
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{
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if(m_tableInitialized)
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return;
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for(int i = 0; i < TableSize; i++)
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m_table[i] = cos((2.0 * M_PI * i) / TableSize);
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m_tableInitialized = true;
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}
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NCO::NCO()
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{
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initTable();
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m_phase = 0;
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m_phaseIncrement = 0;
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}
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void NCO::setFreq(Real freq, Real sampleRate)
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{
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m_phaseIncrement = (unsigned) std::round((freq * 4294967296.0) / sampleRate);
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qDebug("NCO freq: %f phase inc: %u sr: %f", freq, m_phaseIncrement, sampleRate);
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}
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Real NCO::next()
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{
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nextPhase();
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return get();
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}
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Complex NCO::nextIQ()
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{
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nextPhase();
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return getIQ();
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}
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Complex NCO::nextQI()
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{
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Complex iq = nextIQ();
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return Complex(iq.imag(), iq.real());
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}
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void NCO::nextIQMul(Real& i, Real& q)
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{
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Real x = i;
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Real y = q;
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Complex iq = nextIQ();
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i = x*iq.real() - y*iq.imag();
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q = x*iq.imag() + y*iq.real();
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}
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Real NCO::get()
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{
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unsigned intBits = (m_phase >> IntShift) & IntMask;
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unsigned fracBits = m_phase & FracMask;
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unsigned i = intBits;
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unsigned j = (i + 1) & IntMask;
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Real frac = ((Real) fracBits) / Denom;
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return m_table[i] + frac * (m_table[j] - m_table[i]); // Linear interpolation
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}
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Complex NCO::getIQ()
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{
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unsigned intBits = (m_phase >> IntShift) & IntMask;
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unsigned fracBits = m_phase & FracMask;
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unsigned i = intBits;
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unsigned j = (i + 1) & IntMask;
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unsigned k = (i + TableSize / 4) & IntMask;
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unsigned l = (j + TableSize / 4) & IntMask;
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Real frac = ((Real) fracBits) / Denom;
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Real s = m_table[i] + frac * (m_table[j] - m_table[i]); // Linear interpolation for sin
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Real c = m_table[k] + frac * (m_table[l] - m_table[k]); // Linear interpolation for cos
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return Complex(s, -c);
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}
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void NCO::getIQ(Complex& c)
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{
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c = getIQ();
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}
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Complex NCO::getQI()
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{
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Complex iq = getIQ();
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return Complex(iq.imag(), iq.real());
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}
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void NCO::getQI(Complex& c)
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{
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c = getQI();
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}
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