void DemodulatorPreThread::initialize() {
initialized = false;
iqResampleRatio = (double) (params.bandwidth) / (double) params.sampleRate;
audioResampleRatio = (double) (params.audioSampleRate) / (double) params.bandwidth;
float As = 120.0f; // stop-band attenuation [dB]
iqResampler = msresamp_crcf_create(iqResampleRatio, As);
audioResampler = msresamp_rrrf_create(audioResampleRatio, As);
stereoResampler = msresamp_rrrf_create(audioResampleRatio, As);
// Stereo filters / shifters
double firStereoCutoff = ((double) 16000 / (double) params.audioSampleRate);
float ft = ((double) 1000 / (double) params.audioSampleRate); // filter transition
float mu = 0.0f; // fractional timing offset
if (firStereoCutoff < 0) {
firStereoCutoff = 0;
}
if (firStereoCutoff > 0.5) {
firStereoCutoff = 0.5;
}
unsigned int h_len = estimate_req_filter_len(ft, As);
float *h = new float[h_len];
liquid_firdes_kaiser(h_len, firStereoCutoff, As, mu, h);
firStereoLeft = firfilt_rrrf_create(h, h_len);
firStereoRight = firfilt_rrrf_create(h, h_len);
// stereo pilot filter
float bw = params.bandwidth;
if (bw < 100000.0) {
bw = 100000.0;
}
unsigned int order = 5; // filter order
float f0 = ((double) 19000 / bw);
float fc = ((double) 19500 / bw);
float Ap = 1.0f;
As = 60.0f;
iirStereoPilot = iirfilt_crcf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_BANDPASS, LIQUID_IIRDES_SOS, order, fc, f0, Ap, As);
initialized = true;
lastParams = params;
}
//
// AUTOTEST : test multi-stage arbitrary resampler
//
void autotest_msresamp_crcf()
{
// options
unsigned int m = 13; // filter semi-length (filter delay)
float r=0.127115323f; // resampling rate (output/input)
float As=60.0f; // resampling filter stop-band attenuation [dB]
unsigned int n=1200; // number of input samples
float fx=0.0254230646f; // complex input sinusoid frequency (0.2*r)
//float bw=0.45f; // resampling filter bandwidth
//unsigned int npfb=64; // number of filters in bank (timing resolution)
unsigned int i;
// number of input samples (zero-padded)
unsigned int nx = n + m;
// output buffer with extra padding for good measure
unsigned int y_len = (unsigned int) ceilf(1.1 * nx * r) + 4;
// arrays
float complex x[nx];
float complex y[y_len];
// create resampler
msresamp_crcf q = msresamp_crcf_create(r,As);
// generate input signal
float wsum = 0.0f;
for (i=0; i<nx; i++) {
// compute window
float w = i < n ? kaiser(i, n, 10.0f, 0.0f) : 0.0f;
// apply window to complex sinusoid
x[i] = cexpf(_Complex_I*2*M_PI*fx*i) * w;
// accumulate window
wsum += w;
}
// resample
unsigned int ny=0;
unsigned int nw;
for (i=0; i<nx; i++) {
// execute resampler, storing in output buffer
msresamp_crcf_execute(q, &x[i], 1, &y[ny], &nw);
// increment output size
ny += nw;
}
// clean up allocated objects
msresamp_crcf_destroy(q);
//
// analyze resulting signal
//
// check that the actual resampling rate is close to the target
float r_actual = (float)ny / (float)nx;
float fy = fx / r; // expected output frequency
// run FFT and ensure that carrier has moved and that image
// frequencies and distortion have been adequately suppressed
unsigned int nfft = 1 << liquid_nextpow2(ny);
float complex yfft[nfft]; // fft input
float complex Yfft[nfft]; // fft output
for (i=0; i<nfft; i++)
yfft[i] = i < ny ? y[i] : 0.0f;
fft_run(nfft, yfft, Yfft, LIQUID_FFT_FORWARD, 0);
fft_shift(Yfft, nfft); // run FFT shift
// find peak frequency
float Ypeak = 0.0f;
float fpeak = 0.0f;
float max_sidelobe = -1e9f; // maximum side-lobe [dB]
float main_lobe_width = 0.07f; // TODO: figure this out from Kaiser's equations
for (i=0; i<nfft; i++) {
// normalized output frequency
float f = (float)i/(float)nfft - 0.5f;
// scale FFT output appropriately
Yfft[i] /= (r * wsum);
float Ymag = 20*log10f( cabsf(Yfft[i]) );
// find frequency location of maximum magnitude
if (Ymag > Ypeak || i==0) {
Ypeak = Ymag;
fpeak = f;
}
// find peak side-lobe value, ignoring frequencies
// within a certain range of signal frequency
if ( fabsf(f-fy) > main_lobe_width )
max_sidelobe = Ymag > max_sidelobe ? Ymag : max_sidelobe;
}
if (liquid_autotest_verbose) {
// print results
printf(" desired resampling rate : %12.8f\n", r);
printf(" measured resampling rate : %12.8f (%u/%u)\n", r_actual, ny, nx);
printf(" peak spectrum : %12.8f dB (expected 0.0 dB)\n", Ypeak);
printf(" peak frequency : %12.8f (expected %-12.8f)\n", fpeak, fy);
printf(" max sidelobe : %12.8f dB (expected at least %.2f dB)\n", max_sidelobe, -As);
}
CONTEND_DELTA( r_actual, r, 0.01f ); // check actual output sample rate
CONTEND_DELTA( Ypeak, 0.0f, 0.25f ); // peak should be about 0 dB
CONTEND_DELTA( fpeak, fy, 0.01f ); // peak frequency should be nearly 0.2
CONTEND_LESS_THAN( max_sidelobe, -As ); // maximum side-lobe should be sufficiently low
#if 0
// export results for debugging
char filename[] = "msresamp_crcf_autotest.m";
FILE*fid = fopen(filename,"w");
fprintf(fid,"%% %s: auto-generated file\n",filename);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"r = %12.8f;\n", r);
fprintf(fid,"nx = %u;\n", nx);
fprintf(fid,"ny = %u;\n", ny);
fprintf(fid,"nfft = %u;\n", nfft);
fprintf(fid,"Y = zeros(1,nfft);\n");
for (i=0; i<nfft; i++)
fprintf(fid,"Y(%3u) = %12.4e + j*%12.4e;\n", i+1, crealf(Yfft[i]), cimagf(Yfft[i]));
fprintf(fid,"\n\n");
fprintf(fid,"%% plot frequency-domain result\n");
fprintf(fid,"f=[0:(nfft-1)]/nfft-0.5;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"plot(f,20*log10(abs(Y)),'Color',[0.25 0.5 0.0],'LineWidth',2);\n");
fprintf(fid,"grid on;\n");
fprintf(fid,"xlabel('normalized frequency');\n");
fprintf(fid,"ylabel('PSD [dB]');\n");
fprintf(fid,"axis([-0.5 0.5 -120 20]);\n");
fclose(fid);
printf("results written to %s\n",filename);
#endif
}
void SpectrumVisualProcessor::process() {
if (!isOutputEmpty()) {
return;
}
if (!input || input->empty()) {
return;
}
if (fftSizeChanged.load()) {
setup(newFFTSize);
fftSizeChanged.store(false);
}
DemodulatorThreadIQData *iqData;
input->pop(iqData);
if (!iqData) {
return;
}
//Start by locking concurrent access to iqData
std::lock_guard < std::recursive_mutex > lock(iqData->getMonitor());
//then get the busy_lock
std::lock_guard < std::mutex > busy_lock(busy_run);
bool doPeak = peakHold.load() && (peakReset.load() == 0);
if (fft_result.size() != fftSizeInternal) {
if (fft_result.capacity() < fftSizeInternal) {
fft_result.reserve(fftSizeInternal);
fft_result_ma.reserve(fftSizeInternal);
fft_result_maa.reserve(fftSizeInternal);
fft_result_peak.reserve(fftSizeInternal);
}
fft_result.resize(fftSizeInternal);
fft_result_ma.resize(fftSizeInternal);
fft_result_maa.resize(fftSizeInternal);
fft_result_temp.resize(fftSizeInternal);
fft_result_peak.resize(fftSizeInternal);
}
if (peakReset.load() != 0) {
peakReset--;
if (peakReset.load() == 0) {
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_peak[i] = fft_floor_maa;
}
fft_ceil_peak = fft_floor_maa;
fft_floor_peak = fft_ceil_maa;
}
}
std::vector<liquid_float_complex> *data = &iqData->data;
if (data && data->size()) {
unsigned int num_written;
long resampleBw = iqData->sampleRate;
bool newResampler = false;
int bwDiff;
if (is_view.load()) {
if (!iqData->sampleRate) {
iqData->decRefCount();
return;
}
while (resampleBw / SPECTRUM_VZM >= bandwidth) {
resampleBw /= SPECTRUM_VZM;
}
resamplerRatio = (double) (resampleBw) / (double) iqData->sampleRate;
size_t desired_input_size = fftSizeInternal / resamplerRatio;
this->desiredInputSize.store(desired_input_size);
if (iqData->data.size() < desired_input_size) {
// std::cout << "fft underflow, desired: " << desired_input_size << " actual:" << input->data.size() << std::endl;
desired_input_size = iqData->data.size();
}
if (centerFreq != iqData->frequency) {
if ((centerFreq - iqData->frequency) != shiftFrequency || lastInputBandwidth != iqData->sampleRate) {
if (abs(iqData->frequency - centerFreq) < (wxGetApp().getSampleRate() / 2)) {
long lastShiftFrequency = shiftFrequency;
shiftFrequency = centerFreq - iqData->frequency;
nco_crcf_set_frequency(freqShifter, (2.0 * M_PI) * (((double) abs(shiftFrequency)) / ((double) iqData->sampleRate)));
if (is_view.load()) {
long freqDiff = shiftFrequency - lastShiftFrequency;
if (lastBandwidth!=0) {
double binPerHz = double(lastBandwidth) / double(fftSizeInternal);
unsigned int numShift = floor(double(abs(freqDiff)) / binPerHz);
if (numShift < fftSizeInternal/2 && numShift) {
if (freqDiff > 0) {
memmove(&fft_result_ma[0], &fft_result_ma[numShift], (fftSizeInternal-numShift) * sizeof(double));
memmove(&fft_result_maa[0], &fft_result_maa[numShift], (fftSizeInternal-numShift) * sizeof(double));
// memmove(&fft_result_peak[0], &fft_result_peak[numShift], (fftSizeInternal-numShift) * sizeof(double));
// memset(&fft_result_peak[fftSizeInternal-numShift], 0, numShift * sizeof(double));
} else {
memmove(&fft_result_ma[numShift], &fft_result_ma[0], (fftSizeInternal-numShift) * sizeof(double));
memmove(&fft_result_maa[numShift], &fft_result_maa[0], (fftSizeInternal-numShift) * sizeof(double));
// memmove(&fft_result_peak[numShift], &fft_result_peak[0], (fftSizeInternal-numShift) * sizeof(double));
// memset(&fft_result_peak[0], 0, numShift * sizeof(double));
}
}
}
}
}
peakReset.store(PEAK_RESET_COUNT);
}
if (shiftBuffer.size() != desired_input_size) {
if (shiftBuffer.capacity() < desired_input_size) {
shiftBuffer.reserve(desired_input_size);
}
shiftBuffer.resize(desired_input_size);
}
if (shiftFrequency < 0) {
nco_crcf_mix_block_up(freqShifter, &iqData->data[0], &shiftBuffer[0], desired_input_size);
} else {
nco_crcf_mix_block_down(freqShifter, &iqData->data[0], &shiftBuffer[0], desired_input_size);
}
} else {
shiftBuffer.assign(iqData->data.begin(), iqData->data.begin()+desired_input_size);
}
if (!resampler || resampleBw != lastBandwidth || lastInputBandwidth != iqData->sampleRate) {
float As = 60.0f;
if (resampler) {
msresamp_crcf_destroy(resampler);
}
resampler = msresamp_crcf_create(resamplerRatio, As);
bwDiff = resampleBw-lastBandwidth;
lastBandwidth = resampleBw;
lastInputBandwidth = iqData->sampleRate;
newResampler = true;
peakReset.store(PEAK_RESET_COUNT);
}
unsigned int out_size = ceil((double) (desired_input_size) * resamplerRatio) + 512;
if (resampleBuffer.size() != out_size) {
if (resampleBuffer.capacity() < out_size) {
resampleBuffer.reserve(out_size);
}
resampleBuffer.resize(out_size);
}
msresamp_crcf_execute(resampler, &shiftBuffer[0], desired_input_size, &resampleBuffer[0], &num_written);
if (num_written < fftSizeInternal) {
memcpy(fftInData, resampleBuffer.data(), num_written * sizeof(liquid_float_complex));
memset(&(fftInData[num_written]), 0, (fftSizeInternal-num_written) * sizeof(liquid_float_complex));
} else {
memcpy(fftInData, resampleBuffer.data(), fftSizeInternal * sizeof(liquid_float_complex));
}
} else {
this->desiredInputSize.store(fftSizeInternal);
num_written = data->size();
if (data->size() < fftSizeInternal) {
memcpy(fftInData, data->data(), data->size() * sizeof(liquid_float_complex));
memset(&fftInData[data->size()], 0, (fftSizeInternal - data->size()) * sizeof(liquid_float_complex));
} else {
memcpy(fftInData, data->data(), fftSizeInternal * sizeof(liquid_float_complex));
}
}
bool execute = false;
if (num_written >= fftSizeInternal) {
execute = true;
memcpy(fftInput, fftInData, fftSizeInternal * sizeof(liquid_float_complex));
memcpy(fftLastData, fftInput, fftSizeInternal * sizeof(liquid_float_complex));
} else {
if (lastDataSize + num_written < fftSizeInternal) { // priming
unsigned int num_copy = fftSizeInternal - lastDataSize;
if (num_written > num_copy) {
num_copy = num_written;
}
memcpy(fftLastData, fftInData, num_copy * sizeof(liquid_float_complex));
lastDataSize += num_copy;
} else {
unsigned int num_last = (fftSizeInternal - num_written);
memcpy(fftInput, fftLastData + (lastDataSize - num_last), num_last * sizeof(liquid_float_complex));
memcpy(fftInput + num_last, fftInData, num_written * sizeof(liquid_float_complex));
memcpy(fftLastData, fftInput, fftSizeInternal * sizeof(liquid_float_complex));
execute = true;
}
}
if (execute) {
SpectrumVisualData *output = outputBuffers.getBuffer();
if (output->spectrum_points.size() != fftSize * 2) {
output->spectrum_points.resize(fftSize * 2);
}
if (doPeak) {
if (output->spectrum_hold_points.size() != fftSize * 2) {
output->spectrum_hold_points.resize(fftSize * 2);
}
} else {
output->spectrum_hold_points.resize(0);
}
float fft_ceil = 0, fft_floor = 1;
fft_execute(fftPlan);
for (int i = 0, iMax = fftSizeInternal / 2; i < iMax; i++) {
float a = fftOutput[i].real;
float b = fftOutput[i].imag;
float c = sqrt(a * a + b * b);
float x = fftOutput[fftSizeInternal / 2 + i].real;
float y = fftOutput[fftSizeInternal / 2 + i].imag;
float z = sqrt(x * x + y * y);
fft_result[i] = (z);
fft_result[fftSizeInternal / 2 + i] = (c);
}
if (newResampler && lastView) {
if (bwDiff < 0) {
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_temp[i] = fft_result_ma[(fftSizeInternal/4) + (i/2)];
}
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_ma[i] = fft_result_temp[i];
fft_result_temp[i] = fft_result_maa[(fftSizeInternal/4) + (i/2)];
}
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_maa[i] = fft_result_temp[i];
}
} else {
for (size_t i = 0, iMax = fftSizeInternal; i < iMax; i++) {
if (i < fftSizeInternal/4) {
fft_result_temp[i] = 0; // fft_result_ma[fftSizeInternal/4];
} else if (i >= fftSizeInternal - fftSizeInternal/4) {
fft_result_temp[i] = 0; // fft_result_ma[fftSizeInternal - fftSizeInternal/4-1];
} else {
fft_result_temp[i] = fft_result_ma[(i-fftSizeInternal/4)*2];
}
}
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_ma[i] = fft_result_temp[i];
if (i < fftSizeInternal/4) {
fft_result_temp[i] = 0; //fft_result_maa[fftSizeInternal/4];
} else if (i >= fftSizeInternal - fftSizeInternal/4) {
fft_result_temp[i] = 0; // fft_result_maa[fftSizeInternal - fftSizeInternal/4-1];
} else {
fft_result_temp[i] = fft_result_maa[(i-fftSizeInternal/4)*2];
}
}
for (unsigned int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
fft_result_maa[i] = fft_result_temp[i];
}
}
}
for (int i = 0, iMax = fftSizeInternal; i < iMax; i++) {
if (fft_result_maa[i] != fft_result_maa[i]) fft_result_maa[i] = fft_result[i];
fft_result_maa[i] += (fft_result_ma[i] - fft_result_maa[i]) * fft_average_rate;
if (fft_result_ma[i] != fft_result_ma[i]) fft_result_ma[i] = fft_result[i];
fft_result_ma[i] += (fft_result[i] - fft_result_ma[i]) * fft_average_rate;
if (fft_result_maa[i] > fft_ceil || fft_ceil != fft_ceil) {
fft_ceil = fft_result_maa[i];
}
if (fft_result_maa[i] < fft_floor || fft_floor != fft_floor) {
fft_floor = fft_result_maa[i];
}
if (doPeak) {
if (fft_result_maa[i] > fft_result_peak[i]) {
fft_result_peak[i] = fft_result_maa[i];
}
}
}
if (fft_ceil_ma != fft_ceil_ma) fft_ceil_ma = fft_ceil;
fft_ceil_ma = fft_ceil_ma + (fft_ceil - fft_ceil_ma) * 0.05;
if (fft_ceil_maa != fft_ceil_maa) fft_ceil_maa = fft_ceil;
fft_ceil_maa = fft_ceil_maa + (fft_ceil_ma - fft_ceil_maa) * 0.05;
if (fft_floor_ma != fft_floor_ma) fft_floor_ma = fft_floor;
fft_floor_ma = fft_floor_ma + (fft_floor - fft_floor_ma) * 0.05;
if (fft_floor_maa != fft_floor_maa) fft_floor_maa = fft_floor;
fft_floor_maa = fft_floor_maa + (fft_floor_ma - fft_floor_maa) * 0.05;
if (doPeak) {
if (fft_ceil_maa > fft_ceil_peak) {
fft_ceil_peak = fft_ceil_maa;
}
if (fft_floor_maa < fft_floor_peak) {
fft_floor_peak = fft_floor_maa;
}
}
float sf = scaleFactor.load();
double visualRatio = (double(bandwidth) / double(resampleBw));
double visualStart = (double(fftSizeInternal) / 2.0) - (double(fftSizeInternal) * (visualRatio / 2.0));
double visualAccum = 0;
double peak_acc = 0, acc = 0, accCount = 0, i = 0;
double point_ceil = doPeak?fft_ceil_peak:fft_ceil_maa;
double point_floor = doPeak?fft_floor_peak:fft_floor_maa;
for (int x = 0, xMax = output->spectrum_points.size() / 2; x < xMax; x++) {
visualAccum += visualRatio * double(SPECTRUM_VZM);
while (visualAccum >= 1.0) {
unsigned int idx = round(visualStart+i);
if (idx > 0 && idx < fftSizeInternal) {
acc += fft_result_maa[idx];
if (doPeak) {
peak_acc += fft_result_peak[idx];
}
} else {
acc += fft_floor_maa;
if (doPeak) {
peak_acc += fft_floor_maa;
}
}
accCount += 1.0;
visualAccum -= 1.0;
i++;
}
output->spectrum_points[x * 2] = ((float) x / (float) xMax);
if (doPeak) {
output->spectrum_hold_points[x * 2] = ((float) x / (float) xMax);
}
if (accCount) {
output->spectrum_points[x * 2 + 1] = ((log10((acc/accCount)+0.25 - (point_floor-0.75)) / log10((point_ceil+0.25) - (point_floor-0.75))))*sf;
acc = 0.0;
if (doPeak) {
output->spectrum_hold_points[x * 2 + 1] = ((log10((peak_acc/accCount)+0.25 - (point_floor-0.75)) / log10((point_ceil+0.25) - (point_floor-0.75))))*sf;
peak_acc = 0.0;
}
accCount = 0.0;
}
}
if (hideDC.load()) { // DC-spike removal
long long freqMin = centerFreq-(bandwidth/2);
long long freqMax = centerFreq+(bandwidth/2);
long long zeroPt = (iqData->frequency-freqMin);
if (freqMin < iqData->frequency && freqMax > iqData->frequency) {
int freqRange = int(freqMax-freqMin);
int freqStep = freqRange/fftSize;
int fftStart = (zeroPt/freqStep)-(2000/freqStep);
int fftEnd = (zeroPt/freqStep)+(2000/freqStep);
// std::cout << "range:" << freqRange << ", step: " << freqStep << ", start: " << fftStart << ", end: " << fftEnd << std::endl;
if (fftEnd-fftStart < 2) {
fftEnd++;
fftStart--;
}
int numSteps = (fftEnd-fftStart);
int halfWay = fftStart+(numSteps/2);
if ((fftEnd+numSteps/2+1 < (long long) fftSize) && (fftStart-numSteps/2-1 >= 0) && (fftEnd > fftStart)) {
int n = 1;
for (int i = fftStart; i < halfWay; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftStart - n) * 2 + 1];
n++;
}
n = 1;
for (int i = halfWay; i < fftEnd; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftEnd + n) * 2 + 1];
n++;
}
if (doPeak) {
int n = 1;
for (int i = fftStart; i < halfWay; i++) {
output->spectrum_hold_points[i * 2 + 1] = output->spectrum_hold_points[(fftStart - n) * 2 + 1];
n++;
}
n = 1;
for (int i = halfWay; i < fftEnd; i++) {
output->spectrum_hold_points[i * 2 + 1] = output->spectrum_hold_points[(fftEnd + n) * 2 + 1];
n++;
}
}
}
}
}
output->fft_ceiling = point_ceil/sf;
output->fft_floor = point_floor;
output->centerFreq = centerFreq;
output->bandwidth = bandwidth;
distribute(output);
}
}
iqData->decRefCount();
lastView = is_view.load();
}
int main(int argc, char*argv[])
{
// options
float r=1.2f; // resampling rate (output/input)
float As=80.0f; // resampling filter stop-band attenuation [dB]
unsigned int nx=400; // number of input samples
float fc=0.40f; // complex sinusoid frequency
int dopt;
while ((dopt = getopt(argc,argv,"hr:s:n:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'r': r = atof(optarg); break;
case 's': As = atof(optarg); break;
case 'n': nx = atoi(optarg); break;
default:
exit(1);
}
}
// validate input
if (nx == 0) {
fprintf(stderr,"error: %s, number of input samples must be greater than zero\n", argv[0]);
exit(1);
} else if (r <= 0.0f) {
fprintf(stderr,"error: %s, resampling rate must be greater than zero\n", argv[0]);
exit(1);
} else if ( fabsf(log2f(r)) > 10 ) {
fprintf(stderr,"error: %s, resampling rate unreasonable\n", argv[0]);
exit(1);
}
unsigned int i;
// derived values
unsigned int ny_alloc = (unsigned int) (2*(float)nx * r); // allocation for output
// allocate memory for arrays
float complex x[nx];
float complex y[ny_alloc];
// generate input
unsigned int window_len = (3*nx)/4;
for (i=0; i<nx; i++)
x[i] = i < window_len ? cexpf(_Complex_I*2*M_PI*fc*i) * kaiser(i,window_len,10.0f,0.0f) : 0.0f;
// create multi-stage arbitrary resampler object
msresamp_crcf q = msresamp_crcf_create(r,As);
msresamp_crcf_print(q);
float delay = msresamp_crcf_get_delay(q);
// run resampler
unsigned int ny;
msresamp_crcf_execute(q, x, nx, y, &ny);
// print basic results
printf("input samples : %u\n", nx);
printf("output samples : %u\n", ny);
printf("delay : %f samples\n", delay);
// clean up allocated objects
msresamp_crcf_destroy(q);
//
// export output
//
// open/initialize output file
FILE*fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n",OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"\n");
fprintf(fid,"r=%12.8f;\n", r);
fprintf(fid,"delay = %f;\n", delay);
// save input series
fprintf(fid,"nx = %u;\n", nx);
fprintf(fid,"x = zeros(1,nx);\n");
for (i=0; i<nx; i++)
fprintf(fid,"x(%6u) = %12.4e + j*%12.4e;\n", i+1, crealf(x[i]), cimagf(x[i]));
// save output series
fprintf(fid,"ny = %u;\n", ny);
fprintf(fid,"y = zeros(1,ny);\n");
for (i=0; i<ny; i++)
fprintf(fid,"y(%6u) = %12.4e + j*%12.4e;\n", i+1, crealf(y[i]), cimagf(y[i]));
// output results
fprintf(fid,"\n\n");
fprintf(fid,"%% plot frequency-domain result\n");
fprintf(fid,"nfft=1024;\n");
fprintf(fid,"%% estimate PSD, normalize by array length\n");
fprintf(fid,"X=20*log10(abs(fftshift(fft(x,nfft)/length(x))));\n");
fprintf(fid,"Y=20*log10(abs(fftshift(fft(y,nfft)/length(y))));\n");
fprintf(fid,"G = max(X);\n");
fprintf(fid,"X = X - G;\n");
fprintf(fid,"Y = Y - G;\n");
fprintf(fid,"f=[0:(nfft-1)]/nfft-0.5;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"if r>1, fx = f/r; fy = f; %% interpolated\n");
fprintf(fid,"else, fx = f; fy = f*r; %% decimated\n");
fprintf(fid,"end;\n");
fprintf(fid,"plot(fx,X,'Color',[0.5 0.5 0.5],fy,Y,'LineWidth',2);\n");
fprintf(fid,"grid on;\n\n");
fprintf(fid,"xlabel('normalized frequency');\n");
fprintf(fid,"ylabel('PSD [dB]');\n");
fprintf(fid,"legend('original','resampled','location','northeast');");
fprintf(fid,"axis([-0.5 0.5 -120 10]);\n");
fprintf(fid,"\n\n");
fprintf(fid,"%% plot time-domain result\n");
fprintf(fid,"tx=[0:(length(x)-1)];\n");
fprintf(fid,"ty=[0:(length(y)-1)]/r-delay;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(tx,real(x),'-s','Color',[0.5 0.5 0.5],'MarkerSize',1,...\n");
fprintf(fid," ty,real(y),'-s','Color',[0.5 0 0], 'MarkerSize',1);\n");
fprintf(fid," legend('original','resampled','location','northeast');");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('real');\n");
fprintf(fid," grid on;\n\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(tx,imag(x),'-s','Color',[0.5 0.5 0.5],'MarkerSize',1,...\n");
fprintf(fid," ty,imag(y),'-s','Color',[0 0.5 0], 'MarkerSize',1);\n");
fprintf(fid," legend('original','resampled','location','northeast');");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('imag');\n");
fprintf(fid," grid on;\n\n");
fclose(fid);
printf("results written to %s\n",OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main() {
float r=sqrtf(19); // resampling rate (output/input)
unsigned int n=37; // number of input samples
float As=60.0f; // stop-band attenuation [dB]
unsigned int i;
// derived values: number of input, output samples (adjusted for filter delay)
unsigned int nx = 1.4*n;
unsigned int ny_alloc = (unsigned int) (2*(float)nx * r); // allocation for output
// allocate memory for arrays
float complex x[nx];
float complex y[ny_alloc];
// generate input signal (filter pulse with frequency offset)
float hf[n];
liquid_firdes_kaiser(n, 0.08f, 80.0f, 0, hf);
for (i=0; i<nx; i++)
x[i] = (i < n) ? hf[i]*cexpf(_Complex_I*1.17f*i) : 0.0f;
// create resampler
msresamp_crcf q = msresamp_crcf_create(r,As);
float delay = msresamp_crcf_get_delay(q);
// execute resampler, storing in output buffer
unsigned int ny;
msresamp_crcf_execute(q, x, nx, y, &ny);
// print basic results
printf("input samples : %u\n", nx);
printf("output samples : %u\n", ny);
printf("delay : %f samples\n", delay);
// clean up allocated objects
msresamp_crcf_destroy(q);
//
// export output files
//
FILE * fid;
//
// export time plot
//
fid = fopen(OUTPUT_FILENAME_TIME,"w");
fprintf(fid,"# %s: auto-generated file\n\n", OUTPUT_FILENAME_TIME);
fprintf(fid,"reset\n");
fprintf(fid,"set terminal postscript eps enhanced color solid rounded\n");
//fprintf(fid,"set xrange [0:%u];\n",n);
fprintf(fid,"set yrange [-1.2:1.2]\n");
fprintf(fid,"set size ratio 0.3\n");
fprintf(fid,"set xlabel 'Input Sample Index'\n");
fprintf(fid,"set key top right nobox\n");
fprintf(fid,"set ytics -5,1,5\n");
fprintf(fid,"set grid xtics ytics\n");
fprintf(fid,"set grid linetype 1 linecolor rgb '%s' lw 1\n", LIQUID_DOC_COLOR_GRID);
fprintf(fid,"set multiplot layout 2,1 scale 1.0,1.0\n");
fprintf(fid,"# real\n");
fprintf(fid,"set ylabel 'Real'\n");
fprintf(fid,"plot '-' using 1:2 with linespoints pointtype 6 pointsize 0.9 linetype 1 linewidth 1 linecolor rgb '#666666' title 'original',\\\n");
fprintf(fid," '-' using 1:2 with points pointtype 7 pointsize 0.6 linecolor rgb '#008000' title 'resampled'\n");
// export input signal
for (i=0; i<nx; i++)
fprintf(fid,"%12.4e %12.4e %12.4e\n", (float)i, crealf(x[i]), cimagf(x[i]));
fprintf(fid,"e\n");
// export output signal
for (i=0; i<ny; i++)
fprintf(fid,"%12.4e %12.4e %12.4e\n", (float)(i)/r - delay, crealf(y[i]), cimagf(y[i]));
fprintf(fid,"e\n");
fprintf(fid,"# imag\n");
fprintf(fid,"set ylabel 'Imag'\n");
fprintf(fid,"plot '-' using 1:3 with linespoints pointtype 6 pointsize 0.9 linetype 1 linewidth 1 linecolor rgb '#666666' title 'original',\\\n");
fprintf(fid," '-' using 1:3 with points pointtype 7 pointsize 0.6 linecolor rgb '#800000' title 'resampled'\n");
// export input signal
for (i=0; i<nx; i++)
fprintf(fid,"%12.4e %12.4e %12.4e\n", (float)i, crealf(x[i]), cimagf(x[i]));
fprintf(fid,"e\n");
// export output signal
for (i=0; i<ny; i++)
fprintf(fid,"%12.4e %12.4e %12.4e\n", (float)(i)/r - delay, crealf(y[i]), cimagf(y[i]));
fprintf(fid,"e\n");
fprintf(fid,"unset multiplot\n");
// close output file
fclose(fid);
//
// export spectrum plot
//
fid = fopen(OUTPUT_FILENAME_FREQ,"w");
unsigned int nfft = 512;
float complex X[nfft];
float complex Y[nfft];
liquid_doc_compute_psdcf(x, nx, X, nfft, LIQUID_DOC_PSDWINDOW_NONE, 1);
liquid_doc_compute_psdcf(y, ny, Y, nfft, LIQUID_DOC_PSDWINDOW_NONE, 1);
fft_shift(X,nfft);
fft_shift(Y,nfft);
fprintf(fid,"# %s: auto-generated file\n\n", OUTPUT_FILENAME_FREQ);
fprintf(fid,"reset\n");
fprintf(fid,"set terminal postscript eps enhanced color solid rounded\n");
fprintf(fid,"set xrange [-0.5:0.5];\n");
fprintf(fid,"set yrange [-120:20]\n");
fprintf(fid,"set size ratio 0.6\n");
fprintf(fid,"set xlabel 'Normalized Output Frequency'\n");
fprintf(fid,"set ylabel 'Power Spectral Density [dB]'\n");
fprintf(fid,"set key top right nobox\n");
fprintf(fid,"set grid xtics ytics\n");
fprintf(fid,"set pointsize 0.6\n");
fprintf(fid,"set grid linetype 1 linecolor rgb '%s' lw 1\n",LIQUID_DOC_COLOR_GRID);
fprintf(fid,"# real\n");
fprintf(fid,"plot '-' using 1:2 with lines linetype 1 linewidth 4 linecolor rgb '#999999' title 'original',\\\n");
fprintf(fid," '-' using 1:2 with lines linetype 1 linewidth 4 linecolor rgb '#004080' title 'resampled'\n");
// export output
for (i=0; i<nfft; i++) {
float fx = ((float)(i) / (float)nfft - 0.5f) / r;
fprintf(fid,"%12.8f %12.4e\n", fx, 20*log10f(cabsf(X[i])));
}
fprintf(fid,"e\n");
for (i=0; i<nfft; i++) {
float fy = ((float)(i) / (float)nfft - 0.5f);
fprintf(fid,"%12.8f %12.4e\n", fy, 20*log10f(cabsf(Y[i])));
}
fprintf(fid,"e\n");
fclose(fid);
printf("done.\n");
return 0;
}
void DemodulatorWorkerThread::run() {
std::cout << "Demodulator worker thread started.." << std::endl;
commandQueue = (DemodulatorThreadWorkerCommandQueue *)getInputQueue("WorkerCommandQueue");
resultQueue = (DemodulatorThreadWorkerResultQueue *)getOutputQueue("WorkerResultQueue");
while (!terminated) {
bool filterChanged = false;
bool makeDemod = false;
DemodulatorWorkerThreadCommand filterCommand, demodCommand;
DemodulatorWorkerThreadCommand command;
bool done = false;
while (!done) {
commandQueue->pop(command);
switch (command.cmd) {
case DemodulatorWorkerThreadCommand::DEMOD_WORKER_THREAD_CMD_BUILD_FILTERS:
filterChanged = true;
filterCommand = command;
break;
case DemodulatorWorkerThreadCommand::DEMOD_WORKER_THREAD_CMD_MAKE_DEMOD:
makeDemod = true;
demodCommand = command;
break;
default:
break;
}
done = commandQueue->empty();
}
if ((makeDemod || filterChanged) && !terminated) {
DemodulatorWorkerThreadResult result(DemodulatorWorkerThreadResult::DEMOD_WORKER_THREAD_RESULT_FILTERS);
if (filterCommand.sampleRate) {
result.sampleRate = filterCommand.sampleRate;
}
if (makeDemod) {
cModem = Modem::makeModem(demodCommand.demodType);
cModemName = cModem->getName();
cModemType = cModem->getType();
if (demodCommand.settings.size()) {
cModem->writeSettings(demodCommand.settings);
}
result.sampleRate = demodCommand.sampleRate;
wxGetApp().getAppFrame()->updateModemProperties(cModem->getSettings());
}
result.modem = cModem;
if (makeDemod && demodCommand.bandwidth && demodCommand.audioSampleRate) {
if (cModem != nullptr) {
result.bandwidth = cModem->checkSampleRate(demodCommand.bandwidth, demodCommand.audioSampleRate);
cModemKit = cModem->buildKit(result.bandwidth, demodCommand.audioSampleRate);
} else {
cModemKit = nullptr;
}
} else if (filterChanged && filterCommand.bandwidth && filterCommand.audioSampleRate) {
if (cModem != nullptr) {
result.bandwidth = cModem->checkSampleRate(filterCommand.bandwidth, filterCommand.audioSampleRate);
cModemKit = cModem->buildKit(result.bandwidth, filterCommand.audioSampleRate);
} else {
cModemKit = nullptr;
}
} else if (makeDemod) {
cModemKit = nullptr;
}
if (cModem != nullptr) {
cModem->clearRebuildKit();
}
float As = 60.0f; // stop-band attenuation [dB]
if (result.sampleRate && result.bandwidth) {
result.bandwidth = cModem->checkSampleRate(result.bandwidth, makeDemod?demodCommand.audioSampleRate:filterCommand.audioSampleRate);
result.iqResampleRatio = (double) (result.bandwidth) / (double) result.sampleRate;
result.iqResampler = msresamp_crcf_create(result.iqResampleRatio, As);
}
result.modemKit = cModemKit;
result.modemType = cModemType;
result.modemName = cModemName;
resultQueue->push(result);
}
}
std::cout << "Demodulator worker thread done." << std::endl;
}
void SpectrumVisualProcessor::process() {
if (!isOutputEmpty()) {
return;
}
if (!input || input->empty()) {
return;
}
DemodulatorThreadIQData *iqData;
input->pop(iqData);
if (!iqData) {
return;
}
iqData->busy_rw.lock();
busy_run.lock();
std::vector<liquid_float_complex> *data = &iqData->data;
if (data && data->size()) {
SpectrumVisualData *output = outputBuffers.getBuffer();
if (output->spectrum_points.size() < fftSize * 2) {
output->spectrum_points.resize(fftSize * 2);
}
unsigned int num_written;
if (is_view.load()) {
if (!iqData->frequency || !iqData->sampleRate) {
iqData->decRefCount();
iqData->busy_rw.unlock();
busy_run.unlock();
return;
}
resamplerRatio = (double) (bandwidth) / (double) iqData->sampleRate;
int desired_input_size = fftSize / resamplerRatio;
this->desiredInputSize.store(desired_input_size);
if (iqData->data.size() < desired_input_size) {
// std::cout << "fft underflow, desired: " << desired_input_size << " actual:" << input->data.size() << std::endl;
desired_input_size = iqData->data.size();
}
if (centerFreq != iqData->frequency) {
if ((centerFreq - iqData->frequency) != shiftFrequency || lastInputBandwidth != iqData->sampleRate) {
if (abs(iqData->frequency - centerFreq) < (wxGetApp().getSampleRate() / 2)) {
shiftFrequency = centerFreq - iqData->frequency;
nco_crcf_reset(freqShifter);
nco_crcf_set_frequency(freqShifter, (2.0 * M_PI) * (((double) abs(shiftFrequency)) / ((double) iqData->sampleRate)));
}
}
if (shiftBuffer.size() != desired_input_size) {
if (shiftBuffer.capacity() < desired_input_size) {
shiftBuffer.reserve(desired_input_size);
}
shiftBuffer.resize(desired_input_size);
}
if (shiftFrequency < 0) {
nco_crcf_mix_block_up(freqShifter, &iqData->data[0], &shiftBuffer[0], desired_input_size);
} else {
nco_crcf_mix_block_down(freqShifter, &iqData->data[0], &shiftBuffer[0], desired_input_size);
}
} else {
shiftBuffer.assign(iqData->data.begin(), iqData->data.end());
}
if (!resampler || bandwidth != lastBandwidth || lastInputBandwidth != iqData->sampleRate) {
float As = 60.0f;
if (resampler) {
msresamp_crcf_destroy(resampler);
}
resampler = msresamp_crcf_create(resamplerRatio, As);
lastBandwidth = bandwidth;
lastInputBandwidth = iqData->sampleRate;
}
int out_size = ceil((double) (desired_input_size) * resamplerRatio) + 512;
if (resampleBuffer.size() != out_size) {
if (resampleBuffer.capacity() < out_size) {
resampleBuffer.reserve(out_size);
}
resampleBuffer.resize(out_size);
}
msresamp_crcf_execute(resampler, &shiftBuffer[0], desired_input_size, &resampleBuffer[0], &num_written);
resampleBuffer.resize(fftSize);
if (num_written < fftSize) {
for (int i = 0; i < num_written; i++) {
fftInData[i][0] = resampleBuffer[i].real;
fftInData[i][1] = resampleBuffer[i].imag;
}
for (int i = num_written; i < fftSize; i++) {
fftInData[i][0] = 0;
fftInData[i][1] = 0;
}
} else {
for (int i = 0; i < fftSize; i++) {
fftInData[i][0] = resampleBuffer[i].real;
fftInData[i][1] = resampleBuffer[i].imag;
}
}
} else {
num_written = data->size();
if (data->size() < fftSize) {
for (int i = 0, iMax = data->size(); i < iMax; i++) {
fftInData[i][0] = (*data)[i].real;
fftInData[i][1] = (*data)[i].imag;
}
for (int i = data->size(); i < fftSize; i++) {
fftInData[i][0] = 0;
fftInData[i][1] = 0;
}
} else {
for (int i = 0; i < fftSize; i++) {
fftInData[i][0] = (*data)[i].real;
fftInData[i][1] = (*data)[i].imag;
}
}
}
bool execute = false;
if (num_written >= fftSize) {
execute = true;
memcpy(fftwInput, fftInData, fftSize * sizeof(fftwf_complex));
memcpy(fftLastData, fftwInput, fftSize * sizeof(fftwf_complex));
} else {
if (lastDataSize + num_written < fftSize) { // priming
unsigned int num_copy = fftSize - lastDataSize;
if (num_written > num_copy) {
num_copy = num_written;
}
memcpy(fftLastData, fftInData, num_copy * sizeof(fftwf_complex));
lastDataSize += num_copy;
} else {
unsigned int num_last = (fftSize - num_written);
memcpy(fftwInput, fftLastData + (lastDataSize - num_last), num_last * sizeof(fftwf_complex));
memcpy(fftwInput + num_last, fftInData, num_written * sizeof(fftwf_complex));
memcpy(fftLastData, fftwInput, fftSize * sizeof(fftwf_complex));
execute = true;
}
}
if (execute) {
fftwf_execute(fftw_plan);
float fft_ceil = 0, fft_floor = 1;
if (fft_result.size() < fftSize) {
fft_result.resize(fftSize);
fft_result_ma.resize(fftSize);
fft_result_maa.resize(fftSize);
}
for (int i = 0, iMax = fftSize / 2; i < iMax; i++) {
float a = fftwOutput[i][0];
float b = fftwOutput[i][1];
float c = sqrt(a * a + b * b);
float x = fftwOutput[fftSize / 2 + i][0];
float y = fftwOutput[fftSize / 2 + i][1];
float z = sqrt(x * x + y * y);
fft_result[i] = (z);
fft_result[fftSize / 2 + i] = (c);
}
for (int i = 0, iMax = fftSize; i < iMax; i++) {
if (is_view.load()) {
fft_result_maa[i] += (fft_result_ma[i] - fft_result_maa[i]) * fft_average_rate;
fft_result_ma[i] += (fft_result[i] - fft_result_ma[i]) * fft_average_rate;
} else {
fft_result_maa[i] += (fft_result_ma[i] - fft_result_maa[i]) * fft_average_rate;
fft_result_ma[i] += (fft_result[i] - fft_result_ma[i]) * fft_average_rate;
}
if (fft_result_maa[i] > fft_ceil) {
fft_ceil = fft_result_maa[i];
}
if (fft_result_maa[i] < fft_floor) {
fft_floor = fft_result_maa[i];
}
}
fft_ceil_ma = fft_ceil_ma + (fft_ceil - fft_ceil_ma) * 0.05;
fft_ceil_maa = fft_ceil_maa + (fft_ceil_ma - fft_ceil_maa) * 0.05;
fft_floor_ma = fft_floor_ma + (fft_floor - fft_floor_ma) * 0.05;
fft_floor_maa = fft_floor_maa + (fft_floor_ma - fft_floor_maa) * 0.05;
float sf = scaleFactor.load();
for (int i = 0, iMax = fftSize; i < iMax; i++) {
float v = (log10(fft_result_maa[i]+0.25 - (fft_floor_maa-0.75)) / log10((fft_ceil_maa+0.25) - (fft_floor_maa-0.75)));
output->spectrum_points[i * 2] = ((float) i / (float) iMax);
output->spectrum_points[i * 2 + 1] = v*sf;
}
if (hideDC.load()) { // DC-spike removal
long long freqMin = centerFreq-(bandwidth/2);
long long freqMax = centerFreq+(bandwidth/2);
long long zeroPt = (iqData->frequency-freqMin);
if (freqMin < iqData->frequency && freqMax > iqData->frequency) {
int freqRange = int(freqMax-freqMin);
int freqStep = freqRange/fftSize;
int fftStart = (zeroPt/freqStep)-(2000/freqStep);
int fftEnd = (zeroPt/freqStep)+(2000/freqStep);
// std::cout << "range:" << freqRange << ", step: " << freqStep << ", start: " << fftStart << ", end: " << fftEnd << std::endl;
if (fftEnd-fftStart < 2) {
fftEnd++;
fftStart--;
}
int numSteps = (fftEnd-fftStart);
int halfWay = fftStart+(numSteps/2);
if ((fftEnd+numSteps/2+1 < fftSize) && (fftStart-numSteps/2-1 >= 0) && (fftEnd > fftStart)) {
int n = 1;
for (int i = fftStart; i < halfWay; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftStart - n) * 2 + 1];
n++;
}
n = 1;
for (int i = halfWay; i < fftEnd; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftEnd + n) * 2 + 1];
n++;
}
}
}
}
output->fft_ceiling = fft_ceil_maa/sf;
output->fft_floor = fft_floor_maa;
}
distribute(output);
}
iqData->decRefCount();
iqData->busy_rw.unlock();
busy_run.unlock();
}
// main program
int main (int argc, char **argv)
{
// command-line options
int verbose = 1;
int ppm_error = 0;
int gain = 0;
float rx_resamp_rate;
float bandwidth = 800e3f;
int r, n_read;
uint32_t frequency = 100000000;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
uint8_t *buffer;
complex float *buffer_norm;
int dev_index = 0;
int dev_given = 0;
struct sigaction sigact;
normalizer_t *norm;
float kf = 0.1f; // modulation factor
liquid_freqdem_type type = LIQUID_FREQDEM_DELAYCONJ;
//
int d;
while ((d = getopt(argc,argv,"hf:b:B:G:p:s:")) != EOF) {
switch (d) {
case 'h': usage(); return 0;
case 'f': frequency = atof(optarg); break;
case 'b': bandwidth = atof(optarg); break;
case 'B': out_block_size = (uint32_t)atof(optarg); break;
case 'G': gain = (int)(atof(optarg) * 10); break;
case 'p': ppm_error = atoi(optarg); break;
case 's': samp_rate = (uint32_t)atofs(optarg); break;
case 'd':
dev_index = verbose_device_search(optarg);
dev_given = 1;
break;
default: usage(); return 1;
}
}
if (!dev_given) {
dev_index = verbose_device_search("0");
}
if (dev_index < 0) {
exit(1);
}
r = rtlsdr_open(&dev, (uint32_t)dev_index);
if (r < 0) {
fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
exit(1);
}
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
sigaction(SIGPIPE, &sigact, NULL);
/* Set the sample rate */
verbose_set_sample_rate(dev, samp_rate);
/* Set the frequency */
verbose_set_frequency(dev, frequency);
if (0 == gain) {
/* Enable automatic gain */
verbose_auto_gain(dev);
} else {
/* Enable manual gain */
gain = nearest_gain(dev, gain);
verbose_gain_set(dev, gain);
}
verbose_ppm_set(dev, ppm_error);
rx_resamp_rate = bandwidth/samp_rate;
printf("frequency : %10.4f [MHz]\n", frequency*1e-6f);
printf("bandwidth : %10.4f [kHz]\n", bandwidth*1e-3f);
printf("sample rate : %10.4f kHz = %10.4f kHz * %8.6f\n",
samp_rate * 1e-3f,
bandwidth * 1e-3f,
1.0f / rx_resamp_rate);
printf("verbosity : %s\n", (verbose?"enabled":"disabled"));
unsigned int i,j;
// add arbitrary resampling component
msresamp_crcf resamp = msresamp_crcf_create(rx_resamp_rate, 60.0f);
assert(resamp);
//allocate recv buffer
buffer = malloc(out_block_size * sizeof(uint8_t));
assert(buffer);
buffer_norm = malloc(out_block_size * sizeof(complex float));
assert(buffer_norm);
// create buffer for arbitrary resamper output
int b_len = ((int)(out_block_size * rx_resamp_rate) + 64) >> 1;
complex float buffer_resamp[b_len];
int16_t buffer_demod[b_len];
debug("resamp_buffer_len: %d\n", b_len);
norm = normalizer_create();
verbose_reset_buffer(dev);
freqdem dem = freqdem_create(kf,type);
while (!do_exit) {
// grab data from device
r = rtlsdr_read_sync(dev, buffer, out_block_size, &n_read);
if (r < 0) {
fprintf(stderr, "WARNING: sync read failed.\n");
break;
}
if ((bytes_to_read > 0) && (bytes_to_read < (uint32_t)n_read)) {
n_read = bytes_to_read;
do_exit = 1;
}
// push data through arbitrary resampler and give to frame synchronizer
// TODO : apply bandwidth-dependent gain
for (i=0; i<n_read/2; i++) {
// grab sample from usrp buffer
buffer_norm[i] = normalizer_normalize(norm, *((uint16_t*)buffer+i));
}
// push through resampler (one at a time)
unsigned int nw;
float demod;
msresamp_crcf_execute(resamp, buffer_norm, n_read/2, buffer_resamp, &nw);
for(j=0;j<nw;j++)
{
freqdem_demodulate(dem, buffer_resamp[j], &demod);
buffer_demod[j] = to_int16(demod);
}
if (fwrite(buffer_demod, 2, nw, stdout) != (size_t)nw) {
fprintf(stderr, "Short write, samples lost, exiting!\n");
break;
}
if ((uint32_t)n_read < out_block_size) {
fprintf(stderr, "Short read, samples lost, exiting!\n");
break;
}
if (bytes_to_read > 0)
bytes_to_read -= n_read;
}
// destroy objects
freqdem_destroy(dem);
normalizer_destroy(&norm);
msresamp_crcf_destroy(resamp);
rtlsdr_close(dev);
free (buffer);
return 0;
}
// main program
int main (int argc, char **argv)
{
// command-line options
int verbose = 1;
int ppm_error = 0;
int gain = 0;
unsigned int nfft = 64;
float offset = -65.0f;
float scale = 5.0f;
float fft_rate = 10.0f;
float rx_resamp_rate;
float bandwidth = 800e3f;
unsigned int logsize = 4096;
char filename[256] = "rtl_asgram.dat";
int r, n_read;
uint32_t frequency = 100000000;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
uint8_t *buffer;
int dev_index = 0;
int dev_given = 0;
struct sigaction sigact;
normalizer_t *norm;
//
int d;
while ((d = getopt(argc,argv,"hf:b:B:G:n:p:s:o:r:L:F:")) != EOF) {
switch (d) {
case 'h':
usage();
return 0;
case 'f':
frequency = atof(optarg);
break;
case 'b':
bandwidth = atof(optarg);
break;
case 'B':
out_block_size = (uint32_t)atof(optarg);
break;
case 'G':
gain = (int)(atof(optarg) * 10);
break;
case 'n':
nfft = atoi(optarg);
break;
case 'o':
offset = atof(optarg);
break;
case 'p':
ppm_error = atoi(optarg);
break;
case 's':
samp_rate = (uint32_t)atofs(optarg);
break;
case 'r':
fft_rate = atof(optarg);
break;
case 'L':
logsize = atoi(optarg);
break;
case 'F':
strncpy(filename,optarg,255);
break;
case 'd':
dev_index = verbose_device_search(optarg);
dev_given = 1;
break;
default:
usage();
return 1;
}
}
// validate parameters
if (fft_rate <= 0.0f || fft_rate > 100.0f) {
fprintf(stderr,"error: %s, fft rate must be in (0, 100) Hz\n", argv[0]);
exit(1);
}
if (!dev_given) {
dev_index = verbose_device_search("0");
}
if (dev_index < 0) {
exit(1);
}
r = rtlsdr_open(&dev, (uint32_t)dev_index);
if (r < 0) {
fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
exit(1);
}
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
sigaction(SIGPIPE, &sigact, NULL);
/* Set the sample rate */
verbose_set_sample_rate(dev, samp_rate);
/* Set the frequency */
verbose_set_frequency(dev, frequency);
if (0 == gain) {
/* Enable automatic gain */
verbose_auto_gain(dev);
} else {
/* Enable manual gain */
gain = nearest_gain(dev, gain);
verbose_gain_set(dev, gain);
}
verbose_ppm_set(dev, ppm_error);
rx_resamp_rate = bandwidth/samp_rate;
printf("frequency : %10.4f [MHz]\n", frequency*1e-6f);
printf("bandwidth : %10.4f [kHz]\n", bandwidth*1e-3f);
printf("sample rate : %10.4f kHz = %10.4f kHz * %8.6f\n",
samp_rate * 1e-3f,
bandwidth * 1e-3f,
1.0f / rx_resamp_rate);
printf("verbosity : %s\n", (verbose?"enabled":"disabled"));
unsigned int i;
// add arbitrary resampling component
msresamp_crcf resamp = msresamp_crcf_create(rx_resamp_rate, 60.0f);
assert(resamp);
// create buffer for sample logging
windowcf log = windowcf_create(logsize);
// create ASCII spectrogram object
float maxval;
float maxfreq;
char ascii[nfft+1];
ascii[nfft] = '\0'; // append null character to end of string
asgram q = asgram_create(nfft);
asgram_set_scale(q, offset, scale);
// assemble footer
unsigned int footer_len = nfft + 16;
char footer[footer_len+1];
for (i=0; i<footer_len; i++)
footer[i] = ' ';
footer[1] = '[';
footer[nfft/2 + 3] = '+';
footer[nfft + 4] = ']';
sprintf(&footer[nfft+6], "%8.3f MHz", frequency*1e-6f);
unsigned int msdelay = 1000 / fft_rate;
// create/initialize Hamming window
float w[nfft];
for (i=0; i<nfft; i++)
w[i] = hamming(i,nfft);
//allocate recv buffer
buffer = malloc(out_block_size * sizeof(uint8_t));
assert(buffer);
// create buffer for arbitrary resamper output
int b_len = ((int)(out_block_size * rx_resamp_rate) + 64) >> 1;
complex float buffer_resamp[b_len];
debug("resamp_buffer_len: %d", b_len);
// timer to control asgram output
timer t1 = timer_create();
timer_tic(t1);
norm = normalizer_create();
verbose_reset_buffer(dev);
while (!do_exit) {
// grab data from device
r = rtlsdr_read_sync(dev, buffer, out_block_size, &n_read);
if (r < 0) {
fprintf(stderr, "WARNING: sync read failed.\n");
break;
}
if ((bytes_to_read > 0) && (bytes_to_read < (uint32_t)n_read)) {
n_read = bytes_to_read;
do_exit = 1;
}
// push data through arbitrary resampler and give to frame synchronizer
// TODO : apply bandwidth-dependent gain
for (i=0; i<n_read/2; i++) {
// grab sample from usrp buffer
complex float rtlsdr_sample = normalizer_normalize(norm, *((uint16_t*)buffer+i));
// push through resampler (one at a time)
unsigned int nw;
msresamp_crcf_execute(resamp, &rtlsdr_sample, 1, buffer_resamp, &nw);
// push resulting samples into asgram object
asgram_push(q, buffer_resamp, nw);
// write samples to log
windowcf_write(log, buffer_resamp, nw);
}
if ((uint32_t)n_read < out_block_size) {
fprintf(stderr, "Short read, samples lost, exiting!\n");
break;
}
if (bytes_to_read > 0)
bytes_to_read -= n_read;
if (timer_toc(t1) > msdelay*1e-3f) {
// reset timer
timer_tic(t1);
// run the spectrogram
asgram_execute(q, ascii, &maxval, &maxfreq);
// print the spectrogram
printf(" > %s < pk%5.1fdB [%5.2f]\n", ascii, maxval, maxfreq);
printf("%s\r", footer);
fflush(stdout);
}
}
// try to write samples to file
FILE * fid = fopen(filename,"w");
if (fid != NULL) {
// write header
fprintf(fid, "# %s : auto-generated file\n", filename);
fprintf(fid, "#\n");
fprintf(fid, "# num_samples : %u\n", logsize);
fprintf(fid, "# frequency : %12.8f MHz\n", frequency*1e-6f);
fprintf(fid, "# bandwidth : %12.8f kHz\n", bandwidth*1e-3f);
// save results to file
complex float * rc; // read pointer
windowcf_read(log, &rc);
for (i=0; i<logsize; i++)
fprintf(fid, "%12.4e %12.4e\n", crealf(rc[i]), cimagf(rc[i]));
// close it up
fclose(fid);
printf("results written to '%s'\n", filename);
} else {
fprintf(stderr,"error: %s, could not open '%s' for writing\n", argv[0], filename);
}
// destroy objects
normalizer_destroy(&norm);
msresamp_crcf_destroy(resamp);
windowcf_destroy(log);
asgram_destroy(q);
timer_destroy(t1);
rtlsdr_close(dev);
free (buffer);
return 0;
}
void DemodulatorWorkerThread::threadMain() {
std::cout << "Demodulator worker thread started.." << std::endl;
while (!terminated) {
bool filterChanged = false;
DemodulatorWorkerThreadCommand filterCommand;
DemodulatorWorkerThreadCommand command;
bool done = false;
while (!done) {
commandQueue->pop(command);
switch (command.cmd) {
case DemodulatorWorkerThreadCommand::DEMOD_WORKER_THREAD_CMD_BUILD_FILTERS:
filterChanged = true;
filterCommand = command;
break;
default:
break;
}
done = commandQueue->empty();
}
if (filterChanged && !terminated) {
DemodulatorWorkerThreadResult result(DemodulatorWorkerThreadResult::DEMOD_WORKER_THREAD_RESULT_FILTERS);
float As = 60.0f; // stop-band attenuation [dB]
if (filterCommand.sampleRate && filterCommand.bandwidth) {
result.iqResampleRatio = (double) (filterCommand.bandwidth) / (double) filterCommand.sampleRate;
result.iqResampler = msresamp_crcf_create(result.iqResampleRatio, As);
}
if (filterCommand.bandwidth && filterCommand.audioSampleRate) {
result.audioResamplerRatio = (double) (filterCommand.audioSampleRate) / (double) filterCommand.bandwidth;
result.audioResampler = msresamp_rrrf_create(result.audioResamplerRatio, As);
result.stereoResampler = msresamp_rrrf_create(result.audioResamplerRatio, As);
result.audioSampleRate = filterCommand.audioSampleRate;
// Stereo filters / shifters
double firStereoCutoff = ((double) 16000 / (double) filterCommand.audioSampleRate);
float ft = ((double) 1000 / (double) filterCommand.audioSampleRate); // filter transition
float mu = 0.0f; // fractional timing offset
if (firStereoCutoff < 0) {
firStereoCutoff = 0;
}
if (firStereoCutoff > 0.5) {
firStereoCutoff = 0.5;
}
unsigned int h_len = estimate_req_filter_len(ft, As);
float *h = new float[h_len];
liquid_firdes_kaiser(h_len, firStereoCutoff, As, mu, h);
result.firStereoLeft = firfilt_rrrf_create(h, h_len);
result.firStereoRight = firfilt_rrrf_create(h, h_len);
float bw = filterCommand.bandwidth;
if (bw < 100000.0) {
bw = 100000.0;
}
// stereo pilot filter
unsigned int order = 5; // filter order
float f0 = ((double) 19000 / bw);
float fc = ((double) 19500 / bw);
float Ap = 1.0f;
As = 60.0f;
result.iirStereoPilot = iirfilt_crcf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_BANDPASS, LIQUID_IIRDES_SOS, order, fc, f0, Ap, As);
}
if (filterCommand.bandwidth) {
result.bandwidth = filterCommand.bandwidth;
}
if (filterCommand.sampleRate) {
result.sampleRate = filterCommand.sampleRate;
}
resultQueue->push(result);
}
}
std::cout << "Demodulator worker thread done." << std::endl;
}
int main(int argc, char*argv[])
{
// options
float r=0.23175f; // resampling rate (output/input)
float As=60.0f; // resampling filter stop-band attenuation [dB]
unsigned int n=400; // number of input samples
float fc=0.017f; // complex sinusoid frequency
int dopt;
while ((dopt = getopt(argc,argv,"hr:s:n:f:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'r': r = atof(optarg); break;
case 's': As = atof(optarg); break;
case 'n': n = atoi(optarg); break;
case 'f': fc = atof(optarg); break;
default:
exit(1);
}
}
// validate input
if (n == 0) {
fprintf(stderr,"error: %s, number of input samples must be greater than zero\n", argv[0]);
exit(1);
} else if (r <= 0.0f) {
fprintf(stderr,"error: %s, resampling rate must be greater than zero\n", argv[0]);
exit(1);
} else if ( fabsf(log2f(r)) > 10 ) {
fprintf(stderr,"error: %s, resampling rate unreasonable\n", argv[0]);
exit(1);
}
unsigned int i;
// create multi-stage arbitrary resampler object
msresamp_crcf q = msresamp_crcf_create(r,As);
msresamp_crcf_print(q);
float delay = msresamp_crcf_get_delay(q);
// number of input samples (zero-padded)
unsigned int nx = n + (int)ceilf(delay) + 10;
// output buffer with extra padding for good measure
unsigned int ny_alloc = (unsigned int) (2*(float)nx * r); // allocation for output
// allocate memory for arrays
float complex x[nx];
float complex y[ny_alloc];
// generate input signal
float wsum = 0.0f;
for (i=0; i<nx; i++) {
// compute window
float w = i < n ? kaiser(i, n, 10.0f, 0.0f) : 0.0f;
// apply window to complex sinusoid
x[i] = cexpf(_Complex_I*2*M_PI*fc*i) * w;
// accumulate window
wsum += w;
}
// run resampler
unsigned int ny;
msresamp_crcf_execute(q, x, nx, y, &ny);
// clean up allocated objects
msresamp_crcf_destroy(q);
//
// analyze resulting signal
//
// check that the actual resampling rate is close to the target
float r_actual = (float)ny / (float)nx;
float fy = fc / r; // expected output frequency
// run FFT and ensure that carrier has moved and that image
// frequencies and distortion have been adequately suppressed
unsigned int nfft = 1 << liquid_nextpow2(ny);
float complex yfft[nfft]; // fft input
float complex Yfft[nfft]; // fft output
for (i=0; i<nfft; i++)
yfft[i] = i < ny ? y[i] : 0.0f;
fft_run(nfft, yfft, Yfft, LIQUID_FFT_FORWARD, 0);
fft_shift(Yfft, nfft); // run FFT shift
// find peak frequency
float Ypeak = 0.0f;
float fpeak = 0.0f;
float max_sidelobe = -1e9f; // maximum side-lobe [dB]
float main_lobe_width = 0.07f; // TODO: figure this out from Kaiser's equations
for (i=0; i<nfft; i++) {
// normalized output frequency
float f = (float)i/(float)nfft - 0.5f;
// scale FFT output appropriately
float Ymag = 20*log10f( cabsf(Yfft[i] / (r * wsum)) );
// find frequency location of maximum magnitude
if (Ymag > Ypeak || i==0) {
Ypeak = Ymag;
fpeak = f;
}
// find peak side-lobe value, ignoring frequencies
// within a certain range of signal frequency
if ( fabsf(f-fy) > main_lobe_width )
max_sidelobe = Ymag > max_sidelobe ? Ymag : max_sidelobe;
}
// print results and check frequency location
printf("output results:\n");
printf(" output delay : %12.8f samples\n", delay);
printf(" desired resampling rate : %12.8f\n", r);
printf(" measured resampling rate : %12.8f (%u/%u)\n", r_actual, ny, nx);
printf(" peak spectrum : %12.8f dB (expected 0.0 dB)\n", Ypeak);
printf(" peak frequency : %12.8f (expected %-12.8f)\n", fpeak, fy);
printf(" max sidelobe : %12.8f dB (expected at least %.2f dB)\n", max_sidelobe, -As);
//
// export results
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n",OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"delay=%f;\n", delay);
fprintf(fid,"r=%12.8f;\n", r);
fprintf(fid,"nx = %u;\n", nx);
fprintf(fid,"x = zeros(1,nx);\n");
for (i=0; i<nx; i++)
fprintf(fid,"x(%3u) = %12.4e + j*%12.4e;\n", i+1, crealf(x[i]), cimagf(x[i]));
fprintf(fid,"ny = %u;\n", ny);
fprintf(fid,"y = zeros(1,ny);\n");
for (i=0; i<ny; i++)
fprintf(fid,"y(%3u) = %12.4e + j*%12.4e;\n", i+1, crealf(y[i]), cimagf(y[i]));
// time-domain results
fprintf(fid,"\n");
fprintf(fid,"%% plot time-domain result\n");
fprintf(fid,"tx=[0:(length(x)-1)];\n");
fprintf(fid,"ty=[0:(length(y)-1)]/r-delay;\n");
fprintf(fid,"tmin = min(tx(1), ty(1) );\n");
fprintf(fid,"tmax = max(tx(end),ty(end));\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(tx,real(x),'-s','Color',[0.5 0.5 0.5],'MarkerSize',1,...\n");
fprintf(fid," ty,real(y),'-s','Color',[0.5 0 0], 'MarkerSize',1);\n");
fprintf(fid," legend('original','resampled','location','northeast');");
fprintf(fid," axis([tmin tmax -1.2 1.2]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('real');\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(tx,imag(x),'-s','Color',[0.5 0.5 0.5],'MarkerSize',1,...\n");
fprintf(fid," ty,imag(y),'-s','Color',[0 0.5 0], 'MarkerSize',1);\n");
fprintf(fid," legend('original','resampled','location','northeast');");
fprintf(fid," axis([tmin tmax -1.2 1.2]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('imag');\n");
// frequency-domain results
fprintf(fid,"\n\n");
fprintf(fid,"%% plot frequency-domain result\n");
fprintf(fid,"nfft=2^nextpow2(max(nx,ny));\n");
fprintf(fid,"%% estimate PSD, normalize by array length\n");
fprintf(fid,"X=20*log10(abs(fftshift(fft(x,nfft)/length(x))));\n");
fprintf(fid,"Y=20*log10(abs(fftshift(fft(y,nfft)/length(y))));\n");
fprintf(fid,"G=max(X);\n");
fprintf(fid,"X=X-G;\n");
fprintf(fid,"Y=Y-G;\n");
fprintf(fid,"f=[0:(nfft-1)]/nfft-0.5;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"if r>1, fx = f/r; fy = f; %% interpolated\n");
fprintf(fid,"else, fx = f; fy = f*r; %% decimated\n");
fprintf(fid,"end;\n");
fprintf(fid,"plot(fx,X,'LineWidth',1, 'Color',[0.5 0.5 0.5],...\n");
fprintf(fid," fy,Y,'LineWidth',1.5,'Color',[0.1 0.3 0.5]);\n");
fprintf(fid,"grid on;\n");
fprintf(fid,"xlabel('normalized frequency');\n");
fprintf(fid,"ylabel('PSD [dB]');\n");
fprintf(fid,"legend('original','resampled','location','northeast');");
fprintf(fid,"axis([-0.5 0.5 -120 20]);\n");
fclose(fid);
printf("results written to %s\n",OUTPUT_FILENAME);
printf("done.\n");
return 0;
}