VE7UWU/sdrangel
1
0
Fork 0
mirror of https://github.com/f4exb/sdrangel.git synced 2025-04-04 10:38:45 -04:00
Code Issues Projects Releases Wiki Activity

Added a NCO with floating point phase calculation before conversion to int for table indexing. This increases frequency precision and is mandatory for CTCSS tone generator

Browse Source
This commit is contained in:
f4exb 2016-12-19 02:41:31 +01:00
parent 3cfdbe72a0
commit 1e881703e8
4 changed files with 158 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
CMakeLists.txt
View File

@ -118,6 +118,7 @@ set(sdrbase_SOURCES
sdrbase/dsp/lowpass.cpp
sdrbase/dsp/movingaverage.cpp
sdrbase/dsp/nco.cpp
sdrbase/dsp/ncof.cpp
sdrbase/dsp/pidcontroller.cpp
sdrbase/dsp/phaselock.cpp
sdrbase/dsp/samplesinkfifo.cpp
@ -225,6 +226,7 @@ set(sdrbase_HEADERS
sdrbase/dsp/misc.h
sdrbase/dsp/movingaverage.h
sdrbase/dsp/nco.h
sdrbase/dsp/ncof.h
sdrbase/dsp/phasediscri.h
sdrbase/dsp/phaselock.h
sdrbase/dsp/pidcontroller.h

92
sdrbase/dsp/ncof.cpp Normal file
View File

@ -0,0 +1,92 @@
///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2016 Edouard Griffiths, F4EXB //
// //
// 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 as version 3 of the License, or //
// //
// 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 V3 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 <QtGlobal>
#include <stdio.h>
#define _USE_MATH_DEFINES
#include <math.h>
#include "dsp/ncof.h"
Real NCOF::m_table[NCOF::TableSize];
bool NCOF::m_tableInitialized = false;
void NCOF::initTable()
{
if(m_tableInitialized)
return;
for(int i = 0; i < TableSize; i++)
m_table[i] = cos((2.0 * M_PI * i) / TableSize);
m_tableInitialized = true;
}
NCOF::NCOF()
{
initTable();
m_phase = 0.0f;
}
void NCOF::setFreq(Real freq, Real sampleRate)
{
m_phaseIncrement = (freq * TableSize) / sampleRate;
qDebug("NCO freq: %f phase inc %f", freq, m_phaseIncrement);
}
float NCOF::next()
{
int phase = nextPhase();
return m_table[phase];
}
Complex NCOF::nextIQ()
{
int phase = nextPhase();
return Complex(m_table[phase], -m_table[(phase + TableSize / 4) % TableSize]);
}
Complex NCOF::nextQI()
{
int phase = nextPhase();
return Complex(-m_table[(phase + TableSize / 4) % TableSize], m_table[phase]);
}
float NCOF::get()
{
return m_table[(int) m_phase];
}
Complex NCOF::getIQ()
{
return Complex(m_table[(int) m_phase], -m_table[((int) m_phase + TableSize / 4) % TableSize]);
}
void NCOF::getIQ(Complex& c)
{
c.real(m_table[(int) m_phase]);
c.imag(-m_table[((int) m_phase + TableSize / 4) % TableSize]);
}
Complex NCOF::getQI()
{
return Complex(-m_table[((int) m_phase + TableSize / 4) % TableSize], m_table[(int) m_phase]);
}
void NCOF::getQI(Complex& c)
{
c.imag(m_table[(int) m_phase]);
c.real(-m_table[((int) m_phase + TableSize / 4) % TableSize]);
}

62
sdrbase/dsp/ncof.h Normal file
View File

@ -0,0 +1,62 @@
///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2016 Edouard Griffiths, F4EXB //
// //
// 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 as version 3 of the License, or //
// //
// 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 V3 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/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef INCLUDE_NCOF_H
#define INCLUDE_NCOF_H
#include "dsp/dsptypes.h"
#include "util/export.h"
class SDRANGEL_API NCOF {
private:
enum {
TableSize = (1 << 12),
};
static Real m_table[TableSize];
static bool m_tableInitialized;
static void initTable();
Real m_phaseIncrement;
Real m_phase;
public:
NCOF();
void setFreq(Real freq, Real sampleRate);
void setPhase(Real phase) { m_phase = phase; }
int nextPhase() //!< Increment phase and return its integer value
{
m_phase += m_phaseIncrement;
while(m_phase >= TableSize)
m_phase -= TableSize;
while(m_phase < 0)
m_phase += TableSize;
return (int) m_phase;
}
Real next(); //!< Return next real sample
Complex nextIQ(); //!< Return next complex sample
Complex nextQI(); //!< Return next complex sample (reversed)
Real get(); //!< Return current real sample (no phase increment)
Complex getIQ(); //!< Return current complex sample (no phase increment)
void getIQ(Complex& c); //!< Sets to the current complex sample (no phase increment)
Complex getQI(); //!< Return current complex sample (no phase increment, reversed)
void getQI(Complex& c); //!< Sets to the current complex sample (no phase increment, reversed)
};
#endif // INCLUDE_NCO_H

2
sdrbase/sdrbase.pro
View File

@ -62,6 +62,7 @@ SOURCES += mainwindow.cpp\
dsp/lowpass.cpp\
dsp/movingaverage.cpp\
dsp/nco.cpp\
dsp/ncof.cpp\
dsp/pidcontroller.cpp\
dsp/phaselock.cpp\
dsp/samplesinkfifo.cpp\
@ -159,6 +160,7 @@ HEADERS += mainwindow.h\
dsp/misc.h\
dsp/movingaverage.h\
dsp/nco.h\
dsp/ncof.h\
dsp/phasediscri.h\
dsp/phaselock.h\
dsp/pidcontroller.h\