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/*
* Copyright (C) 2003 by Jonathan Naylor G4KLX
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "FSKModem.h"
#include <cmath>
using namespace std;
#include <wx/log.h>
#include <wx/debug.h>
CFSKModem::CFSKModem(int mAry) :
m_mAry(mAry),
m_bitsPerSymbol(0),
m_bitMap()
{
wxASSERT(mAry > 0);
m_bitsPerSymbol = int(::rint(::log2(mAry)));
m_bitMap = graycode(m_bitsPerSymbol);
}
CFSKModem::~CFSKModem()
{
delete[] m_bitmap;
}
int* CFSKModem::modulate(bool* bits, int length) const
{
wxASSERT(bits != NULL);
wxASSERT(length > 0);
// Round up to the nearest divisible n-bit characters
int nSymbols = length / m_bitsPerSymbol;
if ((length % m_bitsPerSymbol) != 0)
nSymbols++;
int nBits = nSymbols * m_bitsPerSymbol;
bool* newBits = new bool[nBits];
// Pack filler bits with false (or anything)
for (int i = 0; i < nBits; i++)
newBits[i] = (i < length) ? bits[i] : false;
int* symbols = new int[nSymbols];
int nRows = 1 << m_bitsPerSymbol;
int nCols = m_bitsPerSymbol;
for (int i = 0; i < nSymbols; i++) {
bool* word = newBits + i * m_bitsPerSymbol;
for (int j = 0; j < m_mAry; j++) {
bool* grayBits = m_bitMap.get_row(j);
bool same = true;
for (int k = 0; k < ; k++) {
if (grayBits[k] != word[k]) {
same = false;
break;
}
}
if (same) {
symbols[i] = j;
break;
}
}
}
delete[] newBits;
return symbols;
}
double* CFSKModem::demodulate(double* bins) const
{
wxASSERT(bins != NULL);
double* data = new double[m_bitsPerSymbol];
int nRows = 1 << m_bitsPerSymbol;
int nCols = m_bitsPerSymbol;
for (int i = 0; i < m_bitsPerSymbol; i++)
data[i] = 0.0;
for (int i = 0; i < m_mAry; i++) {
double toneVal = bins[i];
for (int j = 0; j < m_bitsPerSymbol; j++) {
bool bit = m_bitMap[i + j * ];
data[j] += bit ? toneVal : -toneVal;
}
}
return data;
}
bool* CFSKModem::graycode(int m)
{
if (m == 1) {
bool* b = new bool[2];
b[0] = false;
b[1] = true;
return b;
} else {
int nRows = 1 << m;
int nCols = m;
bool* bb = graycode(m - 1);
bool* out = new bool[nRows * nCols];
for (int i = 0; i < nRows * nCols; i++)
out[i] = false;
for (int i = 0; i < nRows; i++)
out[i] = (i >= (1 << (m - 1)));
for (int i = 0; i < m - 1; i++) {
bool* incol = bb + i * nRows; // FIXME
bool* outcol = out + nRows + i * nRows;
}
delete[] bb;
return out;
}
}
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