Rtty tx and rx (#2977)

2026-09-11 09:09:29 +00:00 · 2026-02-16 14:34:55 +01:00
parent 95eafeb812
commit 794daf5257
21 changed files with 1809 additions and 1 deletions
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2026 HTotoo
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __PROC_RTTY_RX_H__
+#define __PROC_RTTY_RX_H__
+
+#include "baseband_processor.hpp"
+#include "baseband_thread.hpp"
+#include "rssi_thread.hpp"
+#include "message.hpp"
+#include "dsp_decimate.hpp"
+#include "dsp_demodulate.hpp"
+#include "audio_output.hpp"
+#include "dsp_fir_taps.hpp"
+
+class RTTYRxProcessor : public BasebandProcessor {
+   public:
+    void execute(const buffer_c8_t& buffer) override;
+    void on_message(const Message* const message) override;
+
+   private:
+    static constexpr size_t baseband_fs = 3072000;
+
+    // RTTY Config
+    uint16_t baud_rate = 0;  // 0 = Auto-detect
+    uint16_t shift_hz = 170;
+    bool configured = false;
+
+    // DSP Rates
+    // Stage 0: 3.072M / 8 = 384k
+    // Stage 1: 384k / 8   = 48k
+    // Stage 2: 48k / 2    = 24k (Audio/Demod)
+    static constexpr uint32_t decim_0_out_fs = baseband_fs / 8;
+    static constexpr uint32_t decim_1_out_fs = decim_0_out_fs / 8;
+    static constexpr uint32_t final_fs = decim_1_out_fs / 2;  // 24000 Hz
+
+    // Tuning Constants
+    static constexpr int32_t LPF_ALPHA_SHIFT = 2;
+    static constexpr int32_t MIN_SHIFT_SPREAD = 400;
+
+    // Decimation Chain
+    dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0{};
+    dsp::decimate::FIRC16xR16x32Decim8 decim_1{};
+    dsp::decimate::FIRAndDecimateComplex channel_filter{};
+
+    // Demodulator & Audio
+    dsp::demodulate::FM demod{};
+    AudioOutput audio_output{};
+
+    // Buffers
+    std::array<complex16_t, 512> dst_buffer_data{};
+    const buffer_c16_t dst_buffer{dst_buffer_data.data(), dst_buffer_data.size()};
+
+    std::array<int16_t, 32> audio_data{};
+    const buffer_s16_t audio_buffer{audio_data.data(), audio_data.size()};
+
+    // Output Message
+    RTTYDataMessage tx_message{};
+
+    // Demodulator State
+    int32_t fm_val_smoothed = 0;
+
+    // Tracker State
+    int32_t val_max = 0;
+    int32_t val_min = 0;
+    uint8_t decay_timer = 0;
+
+    // Auto-Baud State
+    uint32_t pulse_measure_counter = 0;
+    uint8_t last_bit_state = 0;
+    uint32_t estimated_bit_width = 528;  // ~45 baud @ 24k
+
+    // UART State
+    enum UartState {
+        WAIT_START,
+        CHECK_START,
+        READ_BITS,
+        WAIT_STOP
+    };
+
+    UartState uart_state = WAIT_START;
+    uint32_t samples_per_bit = 528;
+    uint32_t phase_counter = 0;
+    uint8_t bit_counter = 0;
+    uint8_t shift_reg = 0;
+    uint8_t current_slicer_bit = 1;
+
+    // Polarity
+    bool inverted_polarity = true;
+    uint32_t polarity_timer = 0;
+
+    void configure();
+    void process_demodulated_sample(int32_t sample);
+    void update_baud_estimation(uint32_t pulse_width);
+    void append_data(uint8_t raw_baudot_code);
+
+    BasebandThread baseband_thread{baseband_fs, this, baseband::Direction::Receive};
+    RSSIThread rssi_thread{};
+};
+
+#endif /*__PROC_RTTY_RX_H__*/