comicsansg/CubicSDR
comicsansg/CubicSDR
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Experimenting with FM demod options

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This commit is contained in:
Charles J. Cliffe 2014-11-07 13:51:43 -05:00
parent 44e7744855
commit bd7d748e58
3 changed files with 50 additions and 16 deletions
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2
src/CubicSDRDefs.h
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@ -1,6 +1,6 @@
#pragma once
#define BUF_SIZE (16 * 32 * 256)
#define BUF_SIZE (16 * 32 * 128)
#define SRATE 2500000
#define FFT_SIZE BUF_SIZE / 2

59
src/PrimaryGLContext.cpp
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@ -86,7 +86,7 @@ void PrimaryGLContext::Plot(std::vector<float> &points, std::vector<float> &poin
if (points2.size()) {
glPushMatrix();
glTranslatef(-1.0f, 0.5f, 0.0f);
glScalef(2.0f, 0.5f, 1.0f);
glScalef(2.0f, 1.0f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(2, GL_FLOAT, 0, &points2[0]);
glDrawArrays(GL_LINE_STRIP, 0, points2.size() / 2);
@ -239,6 +239,20 @@ void TestGLCanvas::OnKeyDown(wxKeyEvent& event) {
}
}
void multiply2(float ar, float aj, float br, float bj, float *cr, float *cj) {
*cr = ar * br - aj * bj;
*cj = aj * br + ar * bj;
}
float polar_discriminant2(float ar, float aj, float br, float bj) {
float cr, cj;
double angle;
multiply2(ar, aj, br, -bj, &cr, &cj);
angle = atan2(cj, cr);
return (angle / M_PI);
}
void TestGLCanvas::setData(std::vector<signed char> *data) {
if (data && data->size()) {
@ -312,8 +326,8 @@ void TestGLCanvas::setData(std::vector<signed char> *data) {
liquid_float_complex x;
liquid_float_complex y;
x.real = (float) (*data)[i * 2] / 127.0f;
x.imag = (float) (*data)[i * 2 + 1] / 127.0f;
x.real = (1 << 8) * (float) (*data)[i * 2] / 127.0f;
x.imag = (1 << 8) * (float) (*data)[i * 2 + 1] / 127.0f;
firfilt_crcf_push(fir_filter, x); // push input sample
firfilt_crcf_execute(fir_filter, &y); // compute output
@ -369,14 +383,14 @@ void TestGLCanvas::setData(std::vector<signed char> *data) {
fft_ceil_ma = fft_ceil_ma + (fft_ceil - fft_ceil_ma) * 0.05;
fft_ceil_maa = fft_ceil_maa + (fft_ceil - fft_ceil_maa) * 0.05;
fftw_execute(plan[1]);
// fftw_execute(plan[1]);
for (int i = 0, iMax = FFT_SIZE; i < iMax; i++) {
spectrum_points[i * 2 + 1] = fft_result_maa[i] / fft_ceil_maa;
spectrum_points[i * 2] = ((double) i / (double) iMax);
}
float waveform_ceil = 0;
float waveform_ceil = 0, waveform_floor = 0;
std::vector<float> output_buffer;
output_buffer.resize(BUF_SIZE / 2);
@ -399,9 +413,13 @@ void TestGLCanvas::setData(std::vector<signed char> *data) {
waveform_points.resize(BUF_SIZE);
}
int i, pcm = 0;
int16_t pr = pre_r;
int16_t pj = pre_j;
int i;
float pcm = 0;
float pr = pre_r;
float pj = pre_j;
// std::cout << (in[i][0]) << std::endl;
for (i = 0; i < BUF_SIZE / 2; i++) {
// liquid_float_complex x;
// x.real = in[i][0];
@ -412,22 +430,37 @@ void TestGLCanvas::setData(std::vector<signed char> *data) {
// y[0] *= 10000.0;
// y[1] *= 1000.0;
pcm = polar_disc_fast((int)(in[i][0]*60.0), (int)(in[i][1]*60.0), pr, pj);
// pcm = polar_disc_fast((int)(in[i][0]*32000.0), (int)(in[i][1]*32000.0), pr, pj);
pcm = polar_discriminant2(in[i][0],in[i][1], pr, pj);
pr = (int)(in[i][0]*10.0);
pj = (int)(in[i][1]*10.0);
pr = in[i][0];
pj = in[i][1];
output_buffer[i] = (float)pcm/60.0;
output_buffer[i] = (float)pcm + droop_ofs_maa;
if (waveform_ceil < output_buffer[i]) {
waveform_ceil = output_buffer[i];
}
if (waveform_floor > output_buffer[i]) {
waveform_floor = output_buffer[i];
}
}
droop_ofs = -(waveform_ceil+waveform_floor)/2.0;
droop_ofs_ma = droop_ofs_ma + (droop_ofs-droop_ofs_ma)*0.01;
droop_ofs_maa = droop_ofs_maa + (droop_ofs_ma-droop_ofs_maa)*0.01;
// std::cout << "pr: " << pre_r << std::endl;
// std::cout << "pj: " << pre_j << std::endl;
// std::cout << "do:" << droop_ofs_maa << std::endl;
pre_r = pr;
pre_j = pj;
for (int i = 0, iMax = BUF_SIZE / 2; i < iMax; i++) {
waveform_points[i * 2 + 1] = output_buffer[i] / waveform_ceil;
waveform_points[i * 2 + 1] = output_buffer[i]*2.0;
waveform_points[i * 2] = ((double) i / (double) iMax);
}

5
src/PrimaryGLContext.h
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@ -59,8 +59,9 @@ private:
firhilbf fir_hil;
int16_t pre_r;
int16_t pre_j;
float pre_r;
float pre_j;
float droop_ofs, droop_ofs_ma, droop_ofs_maa;
float fft_ceil_ma, fft_ceil_maa;