Added fft relock on demand
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645bc3463f
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66665622bc
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@ -42,6 +42,8 @@ CostasBeaconSync::CostasBeaconSync(float loop_bw,
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loop_freq = 0.0;
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loop_phase = 0.0;
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locked = false;
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bandpass = firfilt_crcf_create(bandpass_taps, banpass_len);
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}
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@ -57,6 +59,8 @@ std::complex<float> CostasBeaconSync::work(std::complex<float> in) {
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float error = costas_sample.imag() * costas_sample.real();
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locked = std::abs(error) < 0.001;
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loop_freq += beta * error;
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loop_phase += loop_freq + alpha * error;
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@ -73,6 +77,10 @@ std::complex<float> CostasBeaconSync::work(std::complex<float> in) {
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return out;
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}
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bool CostasBeaconSync::has_lock() {
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return locked;
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}
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CostasBeaconSync::~CostasBeaconSync() {
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firfilt_crcf_destroy(bandpass);
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}
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@ -18,11 +18,15 @@ class CostasBeaconSync {
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firfilt_crcf bandpass;
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bool locked;
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public:
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CostasBeaconSync(float, float, float);
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~CostasBeaconSync();
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std::complex<float> work(liquid_float_complex);
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bool has_lock();
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};
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#endif
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@ -15,75 +15,82 @@ FFTBeaconFinder::FFTBeaconFinder(int samplingrate) {
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last_center = 0;
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last_center_level = 0.0;
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has_sync = false;
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}
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std::complex<float> FFTBeaconFinder::work(std::complex<float> in) {
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if (next_fft_in <= 0) {
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fft_in[pos] = in;
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pos += 1;
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if (pos == FFT_LEN) {
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pos = 0;
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fft_execute(fft);
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if (next_fft_in <= 0 && !has_sync) {
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fft_in[pos] = in;
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pos += 1;
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if (pos == FFT_LEN) {
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pos = 0;
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fft_execute(fft);
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float fft_max = std::abs(fft_out[0]);
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for (int i = 0; i < FFT_LEN; i++) {
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float mag = std::abs(fft_out[i]);
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if (mag > fft_max) {
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fft_max = mag;
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}
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}
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std::cout << std::endl;
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int last_center_idx = spectral_bin_to_fft_idx(last_center);
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float last_center_val =
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std::abs(fft_out[last_center_idx]) / fft_max;
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if (last_center_val < 0.25) {
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float max_levels = 0;
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int max_center = 0;
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for (int bin = -50; bin <= 50; bin++) {
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int center_idx = spectral_bin_to_fft_idx(bin);
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float center_val = std::abs(fft_out[center_idx]) / fft_max;
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if (center_val > 0.25) {
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int left_idx = spectral_bin_to_fft_idx(bin - 127);
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int right_idx = spectral_bin_to_fft_idx(bin + 127);
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float left_val = std::abs(fft_out[left_idx]) / fft_max;
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float right_val =
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std::abs(fft_out[right_idx]) / fft_max;
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std::cout << bin << " " << left_val << " | "
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<< center_val << " | " << right_val
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<< std::endl;
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if (center_val + left_val + right_val > max_levels) {
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max_levels = center_val + left_val + right_val;
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max_center = bin;
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}
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float fft_max = std::abs(fft_out[0]);
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for (int i = 0; i < FFT_LEN; i++) {
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float mag = std::abs(fft_out[i]);
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if (mag > fft_max) {
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fft_max = mag;
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}
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}
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if (max_levels > 0.0) {
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last_center = max_center;
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std::cout << std::endl;
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float center_freq =
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float(max_center) / FFT_LEN * samplingrate;
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nco_crcf_set_frequency(
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coarse_correction,
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-(2 * M_PI * center_freq) / samplingrate);
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int last_center_idx = spectral_bin_to_fft_idx(last_center);
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float last_center_val =
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std::abs(fft_out[last_center_idx]) / fft_max;
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std::cout << "New center " << center_freq << " "
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<< max_center << std::endl;
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if (last_center_val < 0.25) {
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float max_levels = 0;
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int max_center = 0;
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for (int bin = -50; bin <= 50; bin++) {
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int center_idx = spectral_bin_to_fft_idx(bin);
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float center_val =
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std::abs(fft_out[center_idx]) / fft_max;
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if (center_val > 0.25) {
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int left_idx = spectral_bin_to_fft_idx(bin - 127);
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int right_idx = spectral_bin_to_fft_idx(bin + 127);
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float left_val =
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std::abs(fft_out[left_idx]) / fft_max;
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float right_val =
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std::abs(fft_out[right_idx]) / fft_max;
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std::cout << bin << " " << left_val << " | "
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<< center_val << " | " << right_val
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<< std::endl;
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if (center_val + left_val + right_val >
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max_levels) {
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max_levels = center_val + left_val + right_val;
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max_center = bin;
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}
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}
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}
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if (max_levels > 0.0) {
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last_center = max_center;
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float center_freq =
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float(max_center) / FFT_LEN * samplingrate;
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nco_crcf_set_frequency(
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coarse_correction,
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-(2 * M_PI * center_freq) / samplingrate);
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std::cout << "New center " << center_freq << " "
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<< max_center << std::endl;
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has_sync = true;
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} else {
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std::cout << "No center found!" << std::endl;
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}
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} else {
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std::cout << "No center found!" << std::endl;
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std::cout << "Last center still valid" << std::endl;
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has_sync = true;
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}
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} else {
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std::cout << "Last center still valid" << std::endl;
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}
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next_fft_in = samplingrate / 4;
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}
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} else {
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next_fft_in = samplingrate / 4;
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}
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} else if(next_fft_in > 0){
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next_fft_in--;
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}
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@ -106,6 +113,10 @@ int FFTBeaconFinder::spectral_bin_to_fft_idx(int bin) {
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}
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}
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void FFTBeaconFinder::reset_sync() {
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has_sync = false;
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}
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FFTBeaconFinder::~FFTBeaconFinder() {
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nco_crcf_destroy(coarse_correction);
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fft_destroy_plan(fft);
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@ -23,12 +23,16 @@ class FFTBeaconFinder {
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int last_center;
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float last_center_level;
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bool has_sync;
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int spectral_bin_to_fft_idx(int);
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public:
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FFTBeaconFinder(int);
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~FFTBeaconFinder();
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void reset_sync();
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std::complex<float> work(std::complex<float>);
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};
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@ -70,7 +70,7 @@ blocks:
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alias: ''
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amp: '1'
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comment: ''
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freq: '0.1'
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freq: '0.01'
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maxoutbuf: '0'
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minoutbuf: '0'
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offset: '0'
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@ -158,7 +158,7 @@ blocks:
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alias: ''
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amp: '1'
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comment: ''
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freq: '-10000'
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freq: '-35000'
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maxoutbuf: '0'
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minoutbuf: '0'
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offset: '0'
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@ -15,6 +15,8 @@ int main(int argc, char const* argv[]) {
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FFTBeaconFinder finder(1000000);
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CostasBeaconSync sync(0.03, -0.1, 0.1);
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bool locked = false;
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int sample_count = 0;
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clock_t start_time = clock();
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@ -25,8 +27,13 @@ int main(int argc, char const* argv[]) {
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fread(in_buffer, sizeof(std::complex<float>), buffer_size, input);
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while (len > 0) {
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for (size_t i = 0; i < len; i++) {
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std::complex<float> coarse_synced = finder.work(in_buffer[i]);
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std::complex<float> coarse_synced =
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finder.work(in_buffer[i]);
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std::complex<float> sync_correction = sync.work(coarse_synced);
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if(!sync.has_lock()) {
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//std::cout << "Resetting lock" << std::endl;
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finder.reset_sync();
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}
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out_buffer[i] = coarse_synced * sync_correction;
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}
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