変調波の周波数をもっと高くして実用的なデータ転送速度にする為に搬送波の周波数は高いほうを使います。
ステレオサウンド出力の左右それぞれ二つの変調波を載せて合計4チャンネルの信号を装置に送ります。
搬送波:19kHz, 21kHz
変調波:700Hz
をそれぞれ左右に出力
この時アナログ/デジタル変換にシュミットトリガーを使っていたのですが上手くいかずヒステリシス付きのコンパレータに変更しました。
#include <iostream>
#include <windows.h>
#include <math.h>
#include <MMSystem.h>
#pragma comment (lib, "winmm.lib")
constexpr auto SAMPLING = 192000;
constexpr auto CHANNEL = 2;
constexpr auto BITSPERSAMPLE = 16;
constexpr auto MAXAMP = 32767;
constexpr auto DIV = 4;
constexpr auto BUFFERING = 10;
void createWave(LPWORD lpData, size_t frequency, size_t sampling, WORD amplitude) {
double wavelength = (double)sampling / (double)frequency;
// double pi = 3.14159265359;
for (int i = 0; i < wavelength; i++) {
lpData[i] = (WORD)(amplitude * sin((i*6.28318530718) / wavelength));
}
}
BOOLEAN isON(unsigned char data, size_t bit, size_t bitLength, size_t value) {
int oneByte = 8;
for (int i = 0; i < oneByte; i++) {
unsigned char mask = 0x80 >> i;
if (((data & mask) == mask) &&
// (bitLength * ((bit - oneByte) + i)) <= (value % (bitLength * bit)) &&
// (value % (bitLength * bit)) < (bitLength * ((bit - oneByte + 1) + i))) {
(bitLength * (bit - oneByte + i)) <= (value % (bitLength * bit)) &&
(value % (bitLength * bit)) < (bitLength *(bit - oneByte + 1 + i))) {
return true;
}
}
return false;
}
void addWave(LPWORD param1, LPWORD param2, size_t length) {
for (int i = 0; i < length; i++) {
param1[i] += param2[i];
}
}
DWORD soundOut(
LPWORD* lpWaveData,
HWAVEOUT hWaveOut,
unsigned char data,
size_t bit,
size_t cFrequency,
BOOL reset,
BOOL control
) {
LPWORD lpSinWave;
LPWORD lpWave;
LPWORD lpWaveTemp;
size_t i, j;
size_t cWavelength = SAMPLING / cFrequency;
size_t dataLength;
size_t andSequence = 0;
size_t dWavelength;
size_t dFrequency;
dataLength = (size_t)CHANNEL * (BITSPERSAMPLE / 8) * cWavelength * bit / sizeof(WORD);
if (control == TRUE) {
andSequence = (size_t)CHANNEL * (BITSPERSAMPLE / 8) * cWavelength / sizeof(WORD);
}
lpWave = (LPWORD)calloc(sizeof(WORD), dataLength + andSequence);
for (i = 0; i < dataLength + andSequence; i++) {
lpWave[i] = 0;
}
lpWaveTemp = (LPWORD)calloc(sizeof(WORD), dataLength + andSequence);
lpSinWave = (LPWORD)calloc(sizeof(WORD), SAMPLING);
/* チャンネル1 ********************************/
// シリアルデータ
dFrequency = 21000;
dWavelength = SAMPLING / dFrequency;
createWave(lpSinWave, dFrequency, SAMPLING, MAXAMP / 2);
memset(lpWaveTemp, 0x00, (dataLength + andSequence) * sizeof(WORD));
for (i = 0, j = 0; i < dataLength; i += CHANNEL, ++j) {
lpWaveTemp[i] = lpSinWave[j];
if (j >= dWavelength) { j = 0; }
}
for (i = 0; i < dataLength; i += CHANNEL) {
if (isON(0xff- data, bit, cWavelength * CHANNEL, i)) {
lpWaveTemp[i] = 0;
}
}
addWave(lpWave, lpWaveTemp, dataLength + andSequence);
// 制御データ
if (andSequence > 0) {
dFrequency = 16000;
dWavelength = SAMPLING / dFrequency;
createWave(lpSinWave, dFrequency, SAMPLING, MAXAMP / 2);
memset(lpWaveTemp, 0x00, (dataLength + andSequence) * sizeof(WORD));
for (i = dataLength + andSequence / 2, j = 0; i < dataLength + andSequence; i += CHANNEL, ++j) {
lpWaveTemp[i] = lpSinWave[j];
if (j >= dWavelength) { j = 0; }
}
addWave(lpWave, lpWaveTemp, dataLength + andSequence);
}
/* チャンネル2 ********************************/
// クロック
dFrequency = 21000;
dWavelength = SAMPLING / dFrequency;
createWave(lpSinWave, dFrequency, SAMPLING, MAXAMP / 2);
memset(lpWaveTemp, 0x00, (dataLength + andSequence) * sizeof(WORD));
for (i = 1, j = 0; i < dataLength; i += CHANNEL) {
lpWaveTemp[i] = lpSinWave[j];
++j;
if (j >= dWavelength) { j = 0; }
}
for (i = 1, j = 0; i < dataLength; i += CHANNEL, ++j) {
if (j < cWavelength/1.4) { lpWaveTemp[i] = 0; }
if (j >= cWavelength) { j = 0; }
}
addWave(lpWave, lpWaveTemp, dataLength + andSequence);
// リセット
if (reset == TRUE) {
dFrequency = 16000;
dWavelength = SAMPLING / dFrequency;
createWave(lpSinWave, dFrequency, SAMPLING, MAXAMP / 2);
memset(lpWaveTemp, 0x00, (dataLength + andSequence) * sizeof(WORD));
for (i = 1, j = 0; i < cWavelength/2; i += CHANNEL, ++j) {
lpWaveTemp[i] = lpSinWave[j];
if (j >= dWavelength) { j = 0; }
}
addWave(lpWave, lpWaveTemp, dataLength + andSequence);
}
free(lpSinWave);
free(lpWaveTemp);
*lpWaveData = lpWave;
return (DWORD)(dataLength + andSequence) * sizeof(WORD);
}
int main() {
LPWORD lpWave[BUFFERING];
WAVEHDR whdr[BUFFERING];
WAVEFORMATEX wfe;
HWAVEOUT hWaveOut;
wfe.wFormatTag = WAVE_FORMAT_PCM;
wfe.nChannels = CHANNEL;
wfe.wBitsPerSample = BITSPERSAMPLE;
wfe.nBlockAlign = CHANNEL * BITSPERSAMPLE / 8;
wfe.nSamplesPerSec = SAMPLING;
wfe.nAvgBytesPerSec = wfe.nSamplesPerSec * wfe.nBlockAlign;
for (int i = 0; i < BUFFERING; i++) {
whdr[i].dwFlags = WHDR_BEGINLOOP | WHDR_ENDLOOP;
whdr[i].dwLoops = 1;
lpWave[i] = NULL;
}
std::string str;
std::cout << "2桁毎の16進コードを入力しEnterを押して下さい。（00 ～ FF）" << std::endl;
std::cout << "続けて入力する場合は間を空けないでください。" << std::endl;
std::cout << "Ctrl+Zを入力しEnterで終了します。" << std::endl;
std::cin >> str;
waveOutOpen(&hWaveOut, 0, &wfe, 0, 0, CALLBACK_NULL);
char strData[3];
strData[2] = 0x00;
size_t bit = 9;
// 変調波
size_t frequency = 700;
int freeBuffer = 0;
for (int i = 0, j = 0, k = 0; i < str.size(); i += 2, j++, k++) {
if (j >= BUFFERING) {
j = 0;
}
freeBuffer = j + 1;
if (freeBuffer >= BUFFERING) {
freeBuffer = 0;
}
if (lpWave[freeBuffer] != NULL) {
free(lpWave[freeBuffer]);
lpWave[freeBuffer] = NULL;
}
strData[0] = str[i];
strData[1] = str[(size_t)i + 1];
// 入力された文字列をデータに変換
unsigned char data = (unsigned char)strtol(strData, NULL, 16);
// サウンド出力
if (j % 3 == 0) {
whdr[j].dwBufferLength = soundOut(&lpWave[j], hWaveOut, data, bit, frequency, TRUE, FALSE);
}
else if (j % 3 == 2) {
whdr[j].dwBufferLength = soundOut(&lpWave[j], hWaveOut, data, bit -1, frequency, FALSE, TRUE);
}
else {
whdr[j].dwBufferLength = soundOut(&lpWave[j], hWaveOut, data, bit - 1, frequency, FALSE, FALSE);
}
whdr[j].lpData = (LPSTR)lpWave[j];
waveOutPrepareHeader(hWaveOut, &whdr[j], sizeof(WAVEHDR));
waveOutWrite(hWaveOut, &whdr[j], sizeof(WAVEHDR));
if (k > BUFFERING - 3) {
Sleep((1000 * (DWORD)bit) / (DWORD)frequency);
}
}
int num = (int)str.size() / 2;
if (num == 0) {
num = 1;
}
else if (num > BUFFERING) {
num = BUFFERING;
}
Sleep((1000 * (DWORD)bit * (num + 1)) / (DWORD)frequency);
waveOutReset(hWaveOut);
waveOutClose(hWaveOut);
for (int i = 0; i < num; i++) {
if (lpWave[i] != NULL) {
free(lpWave[i]);
lpWave[i] = NULL;
}
}
}