void feed(buffer_c16_t src, Callback callback) { auto src_p = src.p; while(src_p < &src.p[src.count]) { const uint32_t sample = *__SIMD32(src_p)++; const uint32_t mag_sq = __SMUAD(sample, sample); if( mag_sq > max_squared ) { max_squared = mag_sq; } } count += src.count; const size_t samples_per_update = src.sampling_rate * update_interval; if( count >= samples_per_update ) { const float max_squared_f = max_squared; const float max_db_f = complex16_mag_squared_to_dbv_norm(max_squared_f); const int32_t max_db = max_db_f; const ChannelStatistics statistics { .max_db = max_db, .count = count, }; callback(statistics); max_squared = 0; count = 0; } }
void BasebandProcessor::update_spectrum() { // Called from idle thread (after EVT_MASK_SPECTRUM is flagged) if( channel_spectrum_request_update ) { /* Decimated buffer is full. Compute spectrum. */ std::array<std::complex<float>, 256> samples_swapped; fft_swap(channel_spectrum, samples_swapped); channel_spectrum_request_update = false; fft_c_preswapped(samples_swapped); ChannelSpectrumMessage spectrum_message; for(size_t i=0; i<spectrum_message.spectrum.db.size(); i++) { const auto mag2 = magnitude_squared(samples_swapped[i]); const float db = complex16_mag_squared_to_dbv_norm(mag2); constexpr float mag_scale = 5.0f; const unsigned int v = (db * mag_scale) + 255.0f; spectrum_message.spectrum.db[i] = std::max(0U, std::min(255U, v)); } /* TODO: Rename .db -> .magnitude, or something more (less!) accurate. */ spectrum_message.spectrum.db_count = spectrum_message.spectrum.db.size(); spectrum_message.spectrum.sampling_rate = channel_spectrum_sampling_rate; spectrum_message.spectrum.channel_filter_pass_frequency = channel_filter_pass_frequency; spectrum_message.spectrum.channel_filter_stop_frequency = channel_filter_stop_frequency; shared_memory.application_queue.push(spectrum_message); } }
bool update_stats(const size_t sample_count, const size_t sampling_rate) { count += sample_count; const size_t samples_per_update = sampling_rate * update_interval; if( count >= samples_per_update ) { const float squared_sum_f = squared_sum; const float max_squared_f = max_squared; const float squared_avg_f = squared_sum_f / count; statistics.rms_db = complex16_mag_squared_to_dbv_norm(squared_avg_f); statistics.max_db = complex16_mag_squared_to_dbv_norm(max_squared_f); statistics.count = count; squared_sum = 0; max_squared = 0; count = 0; return true; } else { return false; } }