Adding_WFM_AM_mode_to_Audio_App (#2644)

* Adding_WFM_AM_mode_to_Audio_App
* more precise values for cos and sin theta, fix sen_theta to sin_theta
* fix sen_theta to sin_theta

firmware/application/apps/analog_audio_app.cpp

@@ -114,6 +114,26 @@ WFMOptionsView::WFMOptionsView(
     };
 }
 
+/* WFMAMAptOptionsView *******************************************************/
+
+WFMAMAptOptionsView::WFMAMAptOptionsView(
+    Rect parent_rect,
+    const Style* style)
+    : View{parent_rect} {
+    set_style(style);
+
+    add_children({
+        &label_config,
+        &options_config,
+    });
+
+    freqman_set_bandwidth_option(WFMAM_MODULATION, options_config);  // adding the common message from freqman.cpp to the options_config
+    options_config.set_by_value(receiver_model.wfmam_configuration());
+    options_config.on_change = [this](size_t, OptionsField::value_t n) {
+        receiver_model.set_wfmam_configuration(n);
+    };
+}
+
 /* AMFMAptOptionsView *********************************************************/
 
 AMFMAptOptionsView::AMFMAptOptionsView(
@@ -415,6 +435,12 @@ void AnalogAudioView::on_show_options_modulation() {
             text_ctcss.hidden(true);
             break;
 
+        case ReceiverModel::Mode::WFMAudioAMApt:
+            widget = std::make_unique<WFMAMAptOptionsView>(options_view_rect, Theme::getInstance()->option_active);
+            waterfall.show_audio_spectrum_view(true);
+            text_ctcss.hidden(true);
+            break;
+
         case ReceiverModel::Mode::AMAudioFMApt:
             widget = std::make_unique<AMFMAptOptionsView>(this, options_view_rect, Theme::getInstance()->option_active);
             waterfall.show_audio_spectrum_view(false);
@@ -462,7 +488,10 @@ void AnalogAudioView::update_modulation(ReceiverModel::Mode modulation) {
         case ReceiverModel::Mode::WidebandFMAudio:
             image_tag = portapack::spi_flash::image_tag_wfm_audio;
             break;
-        case ReceiverModel::Mode::AMAudioFMApt:  // TODO pending to update it.
+        case ReceiverModel::Mode::WFMAudioAMApt:
+            image_tag = portapack::spi_flash::image_tag_wfm_audio;
+            break;
+        case ReceiverModel::Mode::AMAudioFMApt:
             image_tag = portapack::spi_flash::image_tag_am_audio;
             break;
         case ReceiverModel::Mode::SpectrumAnalysis:
@@ -501,7 +530,10 @@ void AnalogAudioView::update_modulation(ReceiverModel::Mode modulation) {
         case ReceiverModel::Mode::WidebandFMAudio:
             sampling_rate = 48000;
             break;
-        case ReceiverModel::Mode::AMAudioFMApt:  // TODO  Wefax mode.
+        case ReceiverModel::Mode::WFMAudioAMApt:
+            sampling_rate = 12000;
+            break;
+        case ReceiverModel::Mode::AMAudioFMApt:
             sampling_rate = 12000;
             break;
         default:

firmware/application/apps/analog_audio_app.hpp

@@ -74,7 +74,7 @@ class AMFMAptOptionsView : public View {
 
     OptionsField options_config{
         {3 * 8, 0 * 16},
-        6,  // Max option length chars
+        6,  // Max option length chars  "USB+FM"
         {
             // Using common messages from freqman_ui.cpp In HF USB , Here  we only need USB Audio demod, + post-FM demod fsubcarrier FM tone to get APT signal.
         }};
@@ -132,6 +132,23 @@ class WFMOptionsView : public View {
         }};
 };
 
+class WFMAMAptOptionsView : public View {
+   public:
+    WFMAMAptOptionsView(Rect parent_rect, const Style* style);
+
+   private:
+    Text label_config{
+        {0 * 8, 0 * 16, 2 * 8, 1 * 16},
+        "BW",
+    };
+    OptionsField options_config{
+        {3 * 8, 0 * 16},
+        10,  // Max option char length  "FM+AM(DSB)"
+        {
+            // Using common messages from freqman_ui.cpp
+        }};
+};
+
 class SPECOptionsView : public View {
    public:
     SPECOptionsView(AnalogAudioView* view, Rect parent_rect, const Style* style);
@@ -215,7 +232,7 @@ class AnalogAudioView : public View {
     uint8_t zoom_factor_amfm{0};             // initial zoom factor in AMFM mode
     uint8_t previous_AM_mode_option{0};      // GUI 5 AM modes :  (0..4 ) (DSB9K, DSB6K, USB,LSB, CW). Used to select proper FIR filter (0..11) AM mode  + offset 0 (zoom+1) or +6 (if zoom+2)
     uint8_t previous_zoom{0};                // GUI ZOOM+1, ZOOM+2 , equivalent to two values offset 0 (zoom+1) or +6 (if zoom+2)
-                                             //
+
     app_settings::SettingsManager settings_{
         "rx_audio",
         app_settings::Mode::RX,
@@ -261,7 +278,8 @@ class AnalogAudioView : public View {
             {"NFM ", toUType(ReceiverModel::Mode::NarrowbandFMAudio)},
             {"WFM ", toUType(ReceiverModel::Mode::WidebandFMAudio)},
             {"SPEC", toUType(ReceiverModel::Mode::SpectrumAnalysis)},
-            {"AMFM", toUType(ReceiverModel::Mode::AMAudioFMApt)}  // Added to handle  HF  WeatherFax , SSB (USB demod) + Tone_Subcarrier FM demod
+            {"AMFM", toUType(ReceiverModel::Mode::AMAudioFMApt)},  // Added to handle  HF  WeatherFax , SSB (USB demod) + Tone_Subcarrier FM demod
+            {"FMAM", toUType(ReceiverModel::Mode::WFMAudioAMApt)}  // Added to handle  SAT NOAA APT
         }};
 
     AudioVolumeField field_volume{

firmware/application/apps/ui_freqman.cpp

@@ -45,7 +45,7 @@ using option_db_t = std::pair<std::string_view, int32_t>;
 using options_db_t = std::vector<option_db_t>;
 
 extern options_db_t freqman_modulations;
-extern options_db_t freqman_bandwidths[5];
+extern options_db_t freqman_bandwidths[6];
 // extern options_db_t freqman_steps; // now included via ui_receiver.hpp
 extern options_db_t freqman_steps_short;
 

firmware/application/baseband_api.cpp

@@ -93,9 +93,9 @@ void NBFMConfig::apply(const uint8_t squelch_level) const {
 
 void WFMConfig::apply() const {
     const WFMConfigureMessage message{
-        decim_0,  // 	taps_200k_decim_0 , 	taps_180k_wfm_decim_0, taps_40k_wfm_decim_0
+        decim_0,             // 	Dynamic array 24 taps : taps_200k_decim_0 , 	taps_180k_wfm_decim_0, taps_40k_wfm_decim_0
-        decim_1,  // 	taps_200k_decim_1 or 	taps_180k_wfm_decim_1, taps_40k_wfm_decim_1
+        decim_1,             // 	Dynamic array 16 taps : taps_200k_decim_1 or 	taps_180k_wfm_decim_1, taps_40k_wfm_decim_1
-        taps_64_lp_156_198,
+        taps_64_lp_156_198,  // Fixed channel audio filter 15khz
         75000,
         audio_48k_hpf_30hz_config,
         audio_48k_deemph_2122_6_config};
@@ -103,6 +103,18 @@ void WFMConfig::apply() const {
     audio::set_rate(audio::Rate::Hz_48000);
 }
 
+void WFMAMConfig::apply() const {
+    const WFMAMConfigureMessage message{
+        decim_0,               // 	Fixed 24 taps array : taps_16k0_decim_0
+        decim_1,               // 	Fixed 32 taps array : taps_84k_wfm_decim_1
+        taps_64_lp_1875_2166,  // Fixed channel audio filter , 64 taps array , to filter DSB AM 2k4 carrier before demod. AM .
+        17000,                 // NOAA satellite tx , FM deviation = +-17Khz.
+        apt_audio_12k_notch_2k4_config,
+        apt_audio_12k_lpf_2000hz_config};
+    send_message(&message);
+    audio::set_rate(audio::Rate::Hz_12000);
+}
+
 void set_tone(const uint32_t index, const uint32_t delta, const uint32_t duration) {
     shared_memory.bb_data.tones_data.tone_defs[index].delta = delta;
     shared_memory.bb_data.tones_data.tone_defs[index].duration = duration;

firmware/application/baseband_api.hpp

@@ -56,12 +56,19 @@ struct NBFMConfig {
 };
 
 struct WFMConfig {
-    const fir_taps_real<24> decim_0;  // To handle both WFM filters , 200k and 40K for NOAA APT
+    const fir_taps_real<24> decim_0;  // To handle all 3 WFM filters , 200k, 180k and 40K-
     const fir_taps_real<16> decim_1;
 
     void apply() const;
 };
 
+struct WFMAMConfig {
+    const fir_taps_real<24> decim_0;  // To handle WFM filter   BW=40K for NOAA APT
+    const fir_taps_real<32> decim_1;
+
+    void apply() const;
+};
+
 void set_tone(const uint32_t index, const uint32_t delta, const uint32_t duration);
 void set_tones_config(const uint32_t bw, const uint32_t pre_silence, const uint16_t tone_count, const bool dual_tone, const bool audio_out);
 void kill_tone();

firmware/application/external/debug_pmem/ui_debug_pmem.cpp

@@ -157,6 +157,9 @@ bool DebugDumpView::debug_dump_func() {
         case ReceiverModel::Mode::WidebandFMAudio:
             pmem_dump_file.write_line("modulation: Mode::WidebandFMAudio");
             break;
+        case ReceiverModel::Mode::WFMAudioAMApt:
+            pmem_dump_file.write_line("modulation: Mode::WFMAudioAMApt");
+            break;
         case ReceiverModel::Mode::SpectrumAnalysis:
             pmem_dump_file.write_line("modulation: Mode::SpectrumAnalysis");
             break;

firmware/application/freqman.hpp

@@ -42,7 +42,8 @@ enum freqman_entry_modulation : uint8_t {
     NFM_MODULATION,
     WFM_MODULATION,
     SPEC_MODULATION,
-    AMFM_MODULATION  // Added for Wefax.
+    AMFM_MODULATION,  // Added for HF Wefax.demod APT signal
+    WFMAM_MODULATION  // Added for NOAA 137 Mhz satellite band,  demod APT signal.
 };
 
 // TODO: Can these be removed after Recon is migrated to FreqmanDB?

firmware/application/freqman_db.cpp

@@ -49,10 +49,11 @@ options_t freqman_modulations = {
     {"NFM", 1},
     {"WFM", 2},
     {"SPEC", 3},
-    {"AMFM", 4},
+    {"AMFM", 4},  // To handle HF Wefax AM and FM demod. inside Audio App.
+    {"FMAM", 5},  // To handle NOAA 137 Mhz Sat FM and AM demod inside Audio App.
 };
 
-options_t freqman_bandwidths[5] = {
+options_t freqman_bandwidths[6] = {
     {
         // AM
         {"DSB 9k", 0},
@@ -103,7 +104,11 @@ options_t freqman_bandwidths[5] = {
     },
     {
         // AMFM for Wefax-
-        {"USB+FM", 5},  // Fixed RX demodul AM config Index 5 : USB+FM for Audio Weather fax (WFAX) tones.
+        {"USB+FM", 5},  // Fixed RX demod. AM config Index 5 : USB+FM for Audio Weather fax (WFAX) tones.
+    },
+    {
+        // WFMAM for NOAA satellites,  137 Mhz band
+        {"FM+AM(DSB)", 1},  // Fixed RX demod- WFM config Index 1 : FM+AM  for Audio NOAA APT ones.
     },
 };
 

firmware/application/receiver_model.cpp

@@ -46,7 +46,7 @@ static constexpr std::array<baseband::AMConfig, 12> am_configs{{
     {taps_6k0_decim_1, taps_6k0_decim_2, taps_2k8_usb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_1},                // SSB USB   BW 2K8   (+ 2K8)  SSB ham equipments.
     {taps_6k0_decim_1, taps_6k0_decim_2, taps_2k8_lsb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_1},                // SSB LSB   BW 2K8   (- 2K8)  SSB ham equipments.
     {taps_6k0_decim_1, taps_6k0_decim_2, taps_0k7_usb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_1},                // SSB USB   BW 0K7   (+ 0K7)  To get audio tone from CW Morse, assuming tx shifted +700hz aprox
-    {taps_6k0_decim_1, taps_6k0_decim_2, taps_2k6_usb_wefax_channel, AMConfigureMessage::Modulation::SSB_FM, audio_12k_lpf_1500hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_1},  // SSB USB+FM  to demod. Subcarrier FM Audio Tones to get APT Weather Fax.
+    {taps_6k0_decim_1, taps_6k0_decim_2, taps_2k6_usb_wefax_channel, AMConfigureMessage::Modulation::SSB_FM, apt_audio_12k_lpf_1500hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_1},  // SSB USB+FM  to demod. Subcarrier FM Audio Tones to get APT Weather Fax.
 
     // below options for Waterfall zoom x 2
     {taps_6k0_narrow_decim_1, taps_9k0_decim_2, taps_9k0_dsb_channel, AMConfigureMessage::Modulation::DSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},                // AM DSB-C  BW 9khz  (+-4k5)  commercial EU bandwidth .
@@ -54,7 +54,7 @@ static constexpr std::array<baseband::AMConfig, 12> am_configs{{
     {taps_6k0_narrow_decim_1, taps_6k0_decim_2, taps_2k8_usb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},                // SSB USB   BW 2K8   (+ 2K8)  SSB ham equipments.
     {taps_6k0_narrow_decim_1, taps_6k0_decim_2, taps_2k8_lsb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},                // SSB LSB   BW 2K8   (- 2K8)  SSB ham equipments.
     {taps_6k0_narrow_decim_1, taps_6k0_decim_2, taps_0k7_usb_channel, AMConfigureMessage::Modulation::SSB, audio_12k_hpf_300hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},                // SSB USB   BW 0K7   (+ 0K7)  To get audio tone from CW Morse, assuming tx shifted +700hz aprox
-    {taps_6k0_narrow_decim_1, taps_6k0_decim_2, taps_2k6_usb_wefax_channel, AMConfigureMessage::Modulation::SSB_FM, audio_12k_lpf_1500hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},  // SSB USB+FM  to demod. Subcarrier FM Audio Tones to get APT Weather Fax with waterfall zoom x 2 (we need taps_6k0_narrow_decim_1 to minimize aliasing)
+    {taps_6k0_narrow_decim_1, taps_6k0_decim_2, taps_2k6_usb_wefax_channel, AMConfigureMessage::Modulation::SSB_FM, apt_audio_12k_lpf_1500hz_config, (int)AMConfigureMessage::Zoom_waterfall::ZOOM_x_2},  // SSB USB+FM  to demod. Subcarrier FM Audio Tones to get APT Weather Fax with waterfall zoom x 2 (we need taps_6k0_narrow_decim_1 to minimize aliasing)
 }};
 
 static constexpr std::array<baseband::NBFMConfig, 3> nbfm_configs{{
@@ -69,6 +69,10 @@ static constexpr std::array<baseband::WFMConfig, 3> wfm_configs{{
     {taps_40k_wfm_decim_0, taps_40k_wfm_decim_1},
 }};
 
+static constexpr std::array<baseband::WFMAMConfig, 1> wfmam_configs{{
+    {taps_16k0_decim_0, taps_84k_wfmam_decim_1},
+}};
+
 } /* namespace */
 
 rf::Frequency ReceiverModel::target_frequency() const {
@@ -187,6 +191,17 @@ void ReceiverModel::set_wfm_configuration(uint8_t n) {
     }
 }
 
+uint8_t ReceiverModel::wfmam_configuration() const {
+    return settings_.wfmam_config_index;
+}
+
+void ReceiverModel::set_wfmam_configuration(uint8_t n) {
+    if (n < wfmam_configs.size()) {
+        settings_.wfmam_config_index = n;
+        update_modulation();
+    }
+}
+
 uint8_t ReceiverModel::squelch_level() const {
     return settings_.squelch_level;
 }
@@ -340,6 +355,10 @@ void ReceiverModel::update_modulation() {
             update_wfm_configuration();
             break;
 
+        case Mode::WFMAudioAMApt:
+            update_wfmam_configuration();
+            break;
+
         case Mode::SpectrumAnalysis:
         case Mode::Capture:
             break;
@@ -362,6 +381,10 @@ void ReceiverModel::update_wfm_configuration() {
     wfm_configs[wfm_configuration()].apply();
 }
 
+void ReceiverModel::update_wfmam_configuration() {
+    wfmam_configs[wfmam_configuration()].apply();  // update with different index for Wefax.
+}
+
 void ReceiverModel::update_antenna_bias() {
     if (enabled_)
         radio::set_antenna_bias(portapack::get_antenna_bias());

firmware/application/receiver_model.hpp

@@ -42,7 +42,8 @@ class ReceiverModel {
         WidebandFMAudio = 2,
         SpectrumAnalysis = 3,
         AMAudioFMApt = 4,   // Added to handle  HF  WeatherFax , SSB (USB demod) + Tone_Subcarrier FM demod
-        Capture = 5,
+        WFMAudioAMApt = 5,  // Added to handle SAT Weather map , NOAA 137 Mhz.
+        Capture = 6,
     };
 
     struct settings_t {
@@ -56,6 +57,7 @@ class ReceiverModel {
         Mode mode = Mode::NarrowbandFMAudio;
         uint8_t am_config_index = 0;
         uint8_t amfm_config_index = 0;
+        uint8_t wfmam_config_index = 0;
         uint8_t nbfm_config_index = 0;
         uint8_t wfm_config_index = 0;
         uint8_t squelch_level = 80;
@@ -98,6 +100,9 @@ class ReceiverModel {
     uint8_t wfm_configuration() const;
     void set_wfm_configuration(uint8_t n);
 
+    uint8_t wfmam_configuration() const;
+    void set_wfmam_configuration(uint8_t n);
+
     uint8_t squelch_level() const;
     void set_squelch_level(uint8_t v);
 
@@ -151,6 +156,7 @@ class ReceiverModel {
     void update_amfm_configuration();
     void update_nbfm_configuration();
     void update_wfm_configuration();
+    void update_wfmam_configuration();
 
     void update_antenna_bias();
     void update_headphone_volume();

firmware/baseband/audio_output.cpp

@@ -52,6 +52,19 @@ void AudioOutput::write_unprocessed(const buffer_s16_t& audio) {
         });
 }
 
+void AudioOutput::apt_write(const buffer_s16_t& audio) {
+    std::array<float, 32> audio_f;
+    for (size_t i = 0; i < audio.count; i++) {
+        cur = audio.p[i];
+        cur2 = cur * cur;
+        mag_am = sqrtf(prev2 + cur2 - (2 * prev * cur * cos_theta)) / sin_theta;
+        audio_f[i] = mag_am * ki;  // normalize.
+        prev = cur;
+        prev2 = cur2;
+    }
+    write(buffer_f32_t{audio_f.data(), audio.count, audio.sampling_rate});
+}
+
 void AudioOutput::write(const buffer_s16_t& audio) {
     std::array<float, 32> audio_f;
     for (size_t i = 0; i < audio.count; i++) {
@@ -72,8 +85,8 @@ void AudioOutput::on_block(const buffer_f32_t& audio) {
     if (do_processing) {
         const auto audio_present_now = squelch.execute(audio);
 
-        hpf.execute_in_place(audio);  // IIRBiquadFilter name is "hpf", but we will call with "hpf-coef" for all  except AMFM (WFAX) with "lpf-coef"
+        hpf.execute_in_place(audio);     // IIRBiquadFilter name is "hpf", but we will call with "hpf-coef" for all  except AMFM (WFAX) with "lpf-coef" and notch for WFMAM (NOAA)
-        deemph.execute_in_place(audio);
+        deemph.execute_in_place(audio);  // IIRBiquadFilter name is "deemph", but we will call LPF de-emphasis or  other LPF for WFAM (NOAA).
 
         audio_present_history = (audio_present_history << 1) | (audio_present_now ? 1 : 0);
         audio_present = (audio_present_history != 0);

firmware/baseband/audio_output.hpp

@@ -46,6 +46,7 @@ class AudioOutput {
         const float squelch_threshold = 0.0f);
 
     void write_unprocessed(const buffer_s16_t& audio);
+    void apt_write(const buffer_s16_t& audio);
     void write(const buffer_s16_t& audio);
     void write(const buffer_f32_t& audio);
 
@@ -58,6 +59,10 @@ class AudioOutput {
    private:
     static constexpr float k = 32768.0f;
     static constexpr float ki = 1.0f / k;
+    static constexpr float cos_theta = 0.30901699437494742410f;
+    static constexpr float sin_theta = 0.95105651629515357212f;
+
+    float cur = 0.0f, cur2 = 0.0f, prev = 0.0f, prev2 = 0.0f, mag_am = 0.0f;
 
     BlockDecimator<int16_t, 32> block_buffer_s16{1};
     BlockDecimator<float, 32> block_buffer{1};

firmware/baseband/proc_wefaxrx.cpp

@@ -161,7 +161,7 @@ void WeFaxRx::configure(const WeFaxRxConfigureMessage& message) {
     channel_filter_high_f = taps_2k6_usb_wefax_channel.high_frequency_normalized * channel_filter_input_fs;
     channel_filter_transition = taps_2k6_usb_wefax_channel.transition_normalized * channel_filter_input_fs;
     channel_spectrum.set_decimation_factor(1.0f);
-    audio_output.configure(audio_12k_lpf_1500hz_config);  // hpf in all AM demod modes (AM-6K/9K, USB/LSB,DSB), except Wefax (lpf there).
+    audio_output.configure(apt_audio_12k_lpf_1500hz_config);  // hpf in all AM demod modes (AM-6K/9K, USB/LSB,DSB), except Wefax (lpf there).
 
     lpm = message.lpm;
     ioc_mode = message.ioc;

firmware/baseband/proc_wfm_audio.cpp

@@ -47,23 +47,37 @@ void WidebandFMAudio::execute(const buffer_c8_t& buffer) {
         channel_spectrum.feed(channel, channel_filter_low_f, channel_filter_high_f, channel_filter_transition);
     }
 
-    /* 384kHz complex<int16_t>[256]
+    /* 384kHz complex<int16_t>[256]  for wfm
      * -> FM demodulation
      * -> 384kHz int16_t[256] */
     /* TODO: To improve adjacent channel rejection, implement complex channel filter:
      *		pass < +/- 100kHz, stop > +/- 200kHz
      */
 
-    auto audio_oversampled = demod.execute(channel, work_audio_buffer);
+    /* 96kHz complex<int16_t>[64]  for wfmam NOAA
+     * -> FM demodulation
+     * -> 96kHz int16_t[64] */
 
-    /* 384kHz int16_t[256]
+    auto audio_oversampled = demod.execute(channel, work_audio_buffer);  // fs 384khz wfm , 96khz wfmam for NOAA
+
+    /* 384kHz int16_t[256]     for wfm
      * -> 4th order CIC decimation by 2, gain of 1
      * -> 192kHz int16_t[128] */
+
+    /* 96kHz int16_t[64]     for wfam
+     * -> 4th order CIC decimation by 2, gain of 1
+     * -> 48kHz int16_t[32] */
+
     auto audio_4fs = audio_dec_1.execute(audio_oversampled, work_audio_buffer);
 
-    /* 192kHz int16_t[128]
+    /* 192kHz int16_t[128]   for wfm
      * -> 4th order CIC decimation by 2, gain of 1
      * -> 96kHz int16_t[64] */
+
+    /* 48kHz int16_t[32]     for wfman
+     * -> 4th order CIC decimation by 2, gain of 1
+     * -> 24kHz int16_t[16] */
+
     auto audio_2fs = audio_dec_2.execute(audio_4fs, work_audio_buffer);
 
     // Input: 96kHz int16_t[64]
@@ -118,13 +132,24 @@ void WidebandFMAudio::execute(const buffer_c8_t& buffer) {
             break;
     }
 
-    /* 96kHz int16_t[64]
+    /* 96kHz int16_t[64]         for wfm
      * -> FIR filter, <15kHz (0.156fs) pass, >19kHz (0.198fs) stop, gain of 1
      * -> 48kHz int16_t[32] */
+
+    /* 24kHz int16_t[16]          for wfmam
+     * -> FIR filter, <4.5kHz (0.1875fs) pass, >5.2kHz (0.2166fs) stop, gain of 1
+     * -> 12kHz int16_t[8] */
+
     auto audio = audio_filter.execute(audio_2fs, work_audio_buffer);
 
-    /* -> 48kHz int16_t[32] */
+    /* -> 48kHz int16_t[32]  for wfm  ,   */
-    audio_output.write(audio);
+    /* -> 12kHz int16_t[8]   for wfmam ,  */
+
+    if (decim_1.decimation_factor() == 2) {
+        audio_output.write(audio);  // we are in original wfm , decim_1.decimation_factor == 2
+    } else {
+        audio_output.apt_write(audio);  // we are in added wfmam (noaa), decim_1.decimation_factor == 8
+    }
 }
 
 void WidebandFMAudio::post_message(const buffer_c16_t& data) {
@@ -142,7 +167,11 @@ void WidebandFMAudio::on_message(const Message* const message) {
             break;
 
         case Message::ID::WFMConfigure:
-            configure(*reinterpret_cast<const WFMConfigureMessage*>(message));
+            configure_wfm(*reinterpret_cast<const WFMConfigureMessage*>(message));
+            break;
+
+        case Message::ID::WFMAMConfigure:
+            configure_wfmam(*reinterpret_cast<const WFMAMConfigureMessage*>(message));
             break;
 
         case Message::ID::CaptureConfig:
@@ -154,20 +183,56 @@ void WidebandFMAudio::on_message(const Message* const message) {
     }
 }
 
-void WidebandFMAudio::configure(const WFMConfigureMessage& message) {
+void WidebandFMAudio::configure_wfm(const WFMConfigureMessage& message) {
     constexpr size_t decim_0_input_fs = baseband_fs;
     constexpr size_t decim_0_output_fs = decim_0_input_fs / decim_0.decimation_factor;
-
     constexpr size_t decim_1_input_fs = decim_0_output_fs;
-    constexpr size_t decim_1_output_fs = decim_1_input_fs / decim_1.decimation_factor;
 
-    constexpr size_t demod_input_fs = decim_1_output_fs;
+    decim_0.configure(message.decim_0_filter.taps);
+    // decim_1.configure(message.decim_1_filter.taps);  // Original .
+
+    // TODO dynamic decim1 ,  with decimation 2 / 8 and  16 x taps , / 32 taps .
+    // Temptatively , I splitted, in two WidebandFMAudio::configure_wfm / WidebandFMAudio::configure_wfmam and dynamically /2, /8  (here /2)
+    // decim_1.set<dsp::decimate::FIRC16xR16x16Decim2>().configure(message.decim_1_filter.taps);   // for wfm
+    // decim_1.set<dsp::decimate::FIRC16xR16x32Decim8>().configure(taps_84k_wfmam_decim_1.taps); // for wfmam
+    decim_1.set<dsp::decimate::FIRC16xR16x16Decim2>().configure(message.decim_1_filter.taps);  // for wfm
+    size_t decim_1_output_fs = decim_1_input_fs / decim_1.decimation_factor();                 // wfm , decim_1.decimation_factor() = /2 , if applied after the line : decim_1.set<dsp::decimate::FIRC16xR16x16Decim2>().configure(message.decim_1_filter.taps);
+    size_t demod_input_fs = decim_1_output_fs;
 
     spectrum_interval_samples = decim_1_output_fs / spectrum_rate_hz;
     spectrum_samples = 0;
 
+    channel_filter_low_f = message.decim_1_filter.low_frequency_normalized * decim_1_input_fs;
+    channel_filter_high_f = message.decim_1_filter.high_frequency_normalized * decim_1_input_fs;
+    channel_filter_transition = message.decim_1_filter.transition_normalized * decim_1_input_fs;
+    demod.configure(demod_input_fs, message.deviation);
+    audio_filter.configure(message.audio_filter.taps);
+    audio_output.configure(message.audio_hpf_config, message.audio_deemph_config);
+
+    channel_spectrum.set_decimation_factor(1);
+
+    configured = true;
+}
+
+void WidebandFMAudio::configure_wfmam(const WFMAMConfigureMessage& message) {
+    constexpr size_t decim_0_input_fs = baseband_fs;
+    constexpr size_t decim_0_output_fs = decim_0_input_fs / decim_0.decimation_factor;
+    constexpr size_t decim_1_input_fs = decim_0_output_fs;
+
     decim_0.configure(message.decim_0_filter.taps);
-    decim_1.configure(message.decim_1_filter.taps);
+
+    // decim_1.configure(message.decim_1_filter.taps);  // Original .
+    // TODO dynamic decim1 ,  with decimation 2 / 8 and  16 x taps , / 32 taps .
+    // Temptatively , I splitted, in two WidebandFMAudio::configure_wfm / WidebandFMAudio::configure_wfmam  and dynamically /2, /8 . (here /8)
+    // decim_1.set<dsp::decimate::FIRC16xR16x16Decim2>().configure(message.decim_1_filter.taps);  // for wfm
+    // decim_1.set<dsp::decimate::FIRC16xR16x32Decim8>().configure(message.decim_1_filter.taps);    // for wfmam
+    decim_1.set<dsp::decimate::FIRC16xR16x32Decim8>().configure(message.decim_1_filter.taps);  // for wfmam
+    size_t decim_1_output_fs = decim_1_input_fs / decim_1.decimation_factor();                 // wfmam,  decim_1.decimation_factor() = /8 ,if applied after the line, decim_1.set<dsp::decimate::FIRC16xR16x16Decim2>().configure(message.decim_1_filter.taps);
+    size_t demod_input_fs = decim_1_output_fs;
+
+    spectrum_interval_samples = decim_1_output_fs / spectrum_rate_hz;
+    spectrum_samples = 0;
+
     channel_filter_low_f = message.decim_1_filter.low_frequency_normalized * decim_1_input_fs;
     channel_filter_high_f = message.decim_1_filter.high_frequency_normalized * decim_1_input_fs;
     channel_filter_transition = message.decim_1_filter.transition_normalized * decim_1_input_fs;

firmware/baseband/proc_wfm_audio.hpp

@@ -35,6 +35,46 @@
 #include "audio_output.hpp"
 #include "spectrum_collector.hpp"
 
+#include <array>
+#include <memory>
+#include <tuple>
+#include <variant>
+
+template <typename... Args>
+class MultiDecimator {
+   public:
+    /* Dispatches to the underlying type's execute. */
+    template <typename Source, typename Destination>
+    Destination execute(
+        const Source& src,
+        const Destination& dst) {
+        return std::visit(
+            [&src, &dst](auto&& arg) -> Destination {
+                return arg.execute(src, dst);
+            },
+            decimator_);
+    }
+
+    size_t decimation_factor() const {
+        return std::visit(
+            [](auto&& arg) -> size_t {
+                return arg.decimation_factor;
+            },
+            decimator_);
+    }
+
+    /* Sets this decimator to a new instance of the specified decimator type.
+     * NB: The instance is returned by-ref so 'configure' can easily be called. */
+    template <typename Decimator>
+    Decimator& set() {
+        decimator_ = Decimator{};
+        return std::get<Decimator>(decimator_);
+    }
+
+   private:
+    std::variant<Args...> decimator_{};
+};
+
 class WidebandFMAudio : public BasebandProcessor {
    public:
     void execute(const buffer_c8_t& buffer) override;
@@ -59,7 +99,16 @@ class WidebandFMAudio : public BasebandProcessor {
         complex_audio.size()};
 
     dsp::decimate::FIRC8xR16x24FS4Decim4 decim_0{};
-    dsp::decimate::FIRC16xR16x16Decim2 decim_1{};
+    // dsp::decimate::FIRC16xR16x16Decim2 decim_1{};   //original condition , before adding wfmam
+
+    // decim_1 will handle different types of FIR filters depending on selection.
+    MultiDecimator<
+        dsp::decimate::FIRC16xR16x16Decim2,
+        dsp::decimate::FIRC16xR16x32Decim8>
+        decim_1{};
+
+    // dsp::decimate::FIRC16xR16x32Decim8 decim_1{}; // For FMAM
+
     int32_t channel_filter_low_f = 0;
     int32_t channel_filter_high_f = 0;
     int32_t channel_filter_transition = 0;
@@ -94,7 +143,8 @@ class WidebandFMAudio : public BasebandProcessor {
     BasebandThread baseband_thread{baseband_fs, this, baseband::Direction::Receive};
     RSSIThread rssi_thread{};
 
-    void configure(const WFMConfigureMessage& message);
+    void configure_wfm(const WFMConfigureMessage& message);
+    void configure_wfmam(const WFMAMConfigureMessage& message);
     void capture_config(const CaptureConfigMessage& message);
     void post_message(const buffer_c16_t& data);
 };

firmware/common/dsp_fir_taps.hpp

@@ -1325,6 +1325,128 @@ constexpr fir_taps_real<16> taps_40k_wfm_decim_1 = {
     }},
 };
 
+// WFMAM decimation filters  ////////////////////////////////////////////////
+// Used for NOAA 137 Mhz APT sat demod.
+// IFIR prototype filter: fs=768000, pass=42000, stop=95000, decim=8, fout=96000
+constexpr fir_taps_real<32> taps_84k_wfmam_decim_1 = {
+    .low_frequency_normalized = -42000.0f / 768000.0f,
+    .high_frequency_normalized = 42000.0f / 768000.0f,
+    .transition_normalized = 53000.0f / 768000.0f,
+    .taps = {{
+        13,
+        -6,
+        -47,
+        -116,
+        -207,
+        -294,
+        -332,
+        -266,
+        -39,
+        386,
+        1012,
+        1795,
+        2648,
+        3452,
+        4079,
+        4423,
+        4423,
+        4079,
+        3452,
+        2648,
+        1795,
+        1012,
+        386,
+        -39,
+        -266,
+        -332,
+        -294,
+        -207,
+        -116,
+        -47,
+        -6,
+        13,
+    }},
+};
+
+/* 1st Wideband FM demod baseband filter of audio AM tones ,
+   to pass all DSB band of  AM  fsubcarrier 2.4Khz mod. with APT */
+/* 24kHz int16_t input
+ * -> FIR filter, <4.5kHz (0.1875fs) pass, >5.2kHz (0.2166fs) stop
+ * -> 12kHz int16_t output, gain of 1.0 (I think).
+ * sum(abs(taps)): 125152         , before <125270>, very similar.
+ */
+constexpr fir_taps_real<64> taps_64_lp_1875_2166{
+    .low_frequency_normalized = -0.1875f,
+    .high_frequency_normalized = 0.1875f,
+    .transition_normalized = 0.03f,
+    .taps = {{
+        38,
+        -21,
+        -51,
+        -9,
+        77,
+        82,
+        -50,
+        -168,
+        -67,
+        190,
+        253,
+        -61,
+        -403,
+        -243,
+        356,
+        616,
+        15,
+        -814,
+        -671,
+        550,
+        1335,
+        334,
+        -1527,
+        -1689,
+        725,
+        2978,
+        1455,
+        -3277,
+        -5361,
+        830,
+        13781,
+        24549,
+        24549,
+        13781,
+        830,
+        -5361,
+        -3277,
+        1455,
+        2978,
+        725,
+        -1689,
+        -1527,
+        334,
+        1335,
+        550,
+        -671,
+        -814,
+        15,
+        616,
+        356,
+        -243,
+        -403,
+        -61,
+        253,
+        190,
+        -67,
+        -168,
+        -50,
+        82,
+        77,
+        -9,
+        -51,
+        -21,
+        38,
+    }},
+};
+
 // TPMS decimation filters ////////////////////////////////////////////////
 
 // IFIR image-reject filter: fs=2457600, pass=100000, stop=407200, decim=4, fout=614400

firmware/common/dsp_iir_config.hpp

@@ -56,8 +56,8 @@ constexpr iir_biquad_config_t audio_12k_hpf_300hz_config{
     {1.00000000f, -1.77863178f, 0.80080265f}};
 
 // scipy.signal.butter(2, 1500 / 6000.0, 'low', analog=False)
-constexpr iir_biquad_config_t audio_12k_lpf_1500hz_config{
+constexpr iir_biquad_config_t apt_audio_12k_lpf_1500hz_config{
-    // Added to lpf the audio in wefax mode , before sending to SD card or spk.
+    // Added to lpf the apt audio in wefax mode , before sending to SD card or spk.
     {0.09763107f, 0.19526215f, 0.09763107f},
     {1.00000000f, -0.94280904f, 0.33333333f}};
 
@@ -108,4 +108,15 @@ constexpr iir_biquad_config_t audio_48k_deemph_2122_6_config{
     {0.12264116f, 0.12264116f, 0.00000000f},
     {1.00000000f, -0.75471767f, 0.00000000f}};
 
+// scipy.signal.iirnotch(f0, Q, fs) = signal.iirnotch(2400, 15, 12000)
+constexpr iir_biquad_config_t apt_audio_12k_notch_2k4_config{
+    {0.95977357f, -0.59317269f, 0.95977357f},
+    {1.00000000f, -0.59317269f, 0.91954714f}};
+
+// scipy.signal.butter(2, 2000 / 6000.0, 'low', analog=False)
+constexpr iir_biquad_config_t apt_audio_12k_lpf_2000hz_config{
+    // Added to lpf the apt audio in NOAA mode , before sending to SD card or spk.
+    {0.15505103f, 0.31010205f, 0.15505103f},
+    {1.00000000f, -0.6202041f, 0.24040821f}};
+
 #endif /*__DSP_IIR_CONFIG_H__*/

firmware/common/message.hpp

@@ -130,7 +130,7 @@ class Message {
         WeFaxRxConfigure = 73,
         WeFaxRxStatusData = 74,
         WeFaxRxImageData = 75,
-
+        WFMAMConfigure = 76,
         MAX
     };
 
@@ -584,6 +584,32 @@ class WFMConfigureMessage : public Message {
     const iir_biquad_config_t audio_deemph_config;
 };
 
+class WFMAMConfigureMessage : public Message {
+   public:
+    constexpr WFMAMConfigureMessage(
+        const fir_taps_real<24> decim_0_filter,
+        const fir_taps_real<32> decim_1_filter,
+        const fir_taps_real<64> audio_filter,
+        const size_t deviation,
+        const iir_biquad_config_t audio_hpf_config,
+        const iir_biquad_config_t audio_deemph_config)
+        : Message{ID::WFMAMConfigure},
+          decim_0_filter(decim_0_filter),
+          decim_1_filter(decim_1_filter),
+          audio_filter(audio_filter),
+          deviation{deviation},
+          audio_hpf_config(audio_hpf_config),
+          audio_deemph_config(audio_deemph_config) {
+    }
+
+    const fir_taps_real<24> decim_0_filter;
+    const fir_taps_real<32> decim_1_filter;
+    const fir_taps_real<64> audio_filter;
+    const size_t deviation;
+    const iir_biquad_config_t audio_hpf_config;
+    const iir_biquad_config_t audio_deemph_config;
+};
+
 class AMConfigureMessage : public Message {
    public:
     enum class Modulation : int32_t {