80 lines
2.6 KiB
C++
80 lines
2.6 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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// //
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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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// //
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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 <stdio.h>
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#define _USE_MATH_DEFINES
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#include <math.h>
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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 * (Real)i) / ((Real)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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}
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void NCO::setFreq(Real freq, Real sampleRate)
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{
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if(sampleRate > 0) {
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m_phaseIncrement = (freq * TableSize) / sampleRate;
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if(m_phaseIncrement != 0)
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qDebug("NCO phase inc %d (period %f)", m_phaseIncrement, (Real)TableSize / (Real)m_phaseIncrement);
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else qDebug("NCO phase inc %d (period oo)", m_phaseIncrement);
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} else {
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qDebug("cannot calculate NCO phase increment since samplerate is 0");
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m_phaseIncrement = 1;
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}
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}
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float NCO::next()
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{
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m_phase += m_phaseIncrement;
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while(m_phase >= TableSize)
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m_phase -= TableSize;
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while(m_phase < 0)
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m_phase += TableSize;
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return m_table[m_phase];
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}
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Complex NCO::nextIQ()
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{
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m_phase += m_phaseIncrement;
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while(m_phase >= TableSize)
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m_phase -= TableSize;
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while(m_phase < 0)
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m_phase += TableSize;
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int idxQuad = (m_phase + (TableSize / 4) + (TableSize / 2)) % TableSize;
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return Complex(m_table[m_phase], m_table[idxQuad]);
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}
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