Small error correction to PR 1367 (#1368)

* Solve_low_bit_rate_150k_Capture_App

* Applying  review comments.

* format issues

* Adding back requested previous low bit rates

firmware/application/apps/capture_app.cpp

@@ -86,7 +86,7 @@ CaptureAppView::CaptureAppView(NavigationView& nav)
     };
 
     receiver_model.enable();
-    option_bandwidth.set_selected_index(7);  // Preselected default option 500kHz.
+    option_bandwidth.set_by_value(500000);  // better by_value than by option_bandwidth.set_selected_index(4), Preselected default option 500kHz.
 
     record_view.on_error = [&nav](std::string message) {
         nav.display_modal("Error", message);

firmware/application/freqman_db.cpp

@@ -76,16 +76,17 @@ options_t freqman_bandwidths[4] = {
         // SPEC -- TODO: these should be indexes.
         {"12k5", 12500},
         {"16k", 16000},
-        {"20k", 20000},
         {"25k", 25000},
         {"50k", 50000},
         {"100k", 100000},
+        {"150k", 150000},
         {"250k", 250000},
         {"500k", 500000}, /* Previous Limit bandwith Option with perfect micro SD write .C16 format operaton.*/
-        {"600k", 600000}, /* That extended option is still possible to record with FW version Mayhem v1.41 (< 2,5MB/sec) */
+        {"600k", 600000}, /* We doubled x2 previous REC BW limit , now extended BW from 600k to 1M with fast enough SD card in C16 or C8 format .*/
         {"650k", 650000},
-        {"750k", 750000}, /* From this BW onwards, the LCD is ok, but the recorded file is decimated, (not real file size) */
-        {"1100k", 1100000},
+        {"750k", 750000},
+        {"1000k", 1000000}, /* New limit bandwith option for recording in C16 (in fast SD card) or in C8 */
+        {"1500k", 1500000}, /* From this BW onwards, the LCD is ok, but M4 CPU is having periodical sample rec dropps, (not real file size, accelerated replay) */
         {"1750k", 1750000},
         {"2000k", 2000000},
         {"2500k", 2500000},

firmware/application/ui/ui_spectrum.cpp

@@ -383,26 +383,30 @@ void WaterfallView::on_audio_spectrum() {
 // TODO: Comments below refer to a fixed oversample rate (8x), cleanup.
 uint32_t filter_bandwidth_for_sampling_rate(int32_t sampling_rate) {
     switch (sampling_rate) {   // Use the var fs (sampling_rate) to set up BPF aprox < fs_max / 2 by Nyquist theorem.
-        case 0 ... 2'000'000:  // BW Captured range (0 <= 250kHz max)  fs = 8 x 250 kHz.
+        case 0 ... 3'000'000:  // BW Captured range (0 <= 250kHz max)  fs = 8 x 250 kHz., 16 x 150 khz, 32 x 75 khz, , 64 x 40 khz
             return 1'750'000;  // Minimum BPF MAX2837 for all those lower BW options.
 
         case 4'000'000 ... 6'000'000:  // BW capture range (500k...750kHz max)  fs_max = 8 x 750kHz = 6Mhz
                                        // BW 500k...750kHz, ex. 500kHz (fs = 8 x BW = 4Mhz), BW 600kHz (fs = 4,8Mhz), BW 750 kHz (fs = 6Mhz).
             return 2'500'000;          // In some IC, MAX2837 appears as 2250000, but both work similarly.
 
-        case 8'800'000:  // BW capture 1,1Mhz fs = 8 x 1,1Mhz = 8,8Mhz. (1Mhz showed slightly higher noise background).
-            return 3'500'000;
+        case 8'000'000:        // BW capture 1Mhz fs = 8 x 1Mhz = 8Mhz. (1Mhz showed slightly higher noise background).
+            return 3'500'000;  // some low SD cards, if not showing avg. writting speed >4MB/sec, they will produce sammples drop at REC with 1MB and C16 format.
+
+        case 12'000'000:  // BW capture 1,5Mhz, fs = 8 x 1,5Mhz = 12Mhz
+                          // Good BPF, good matching, we have some periodical M4 % samples drop.
+            return 5'000'000;
 
         case 14'000'000:  // BW capture 1,75Mhz, fs = 8 x 1,75Mhz = 14Mhz
-                          // Good BPF, good matching, but LCD flickers, refresh rate should be < 20 Hz, reasonable picture.
+                          // Good BPF, good matching, we have some periodical M4 % samples drop.
             return 5'000'000;
 
         case 16'000'000:  // BW capture 2Mhz, fs = 8 x 2Mhz = 16Mhz
-                          // Good BPF, good matching, but LCD flickers, refresh rate should be < 20 Hz, reasonable picture.
+                          // Good BPF, good matching, we have some periodical M4 % samples drop.
             return 6'000'000;
 
         case 20'000'000:  // BW capture 2,5Mhz, fs = 8 x 2,5 Mhz = 20Mhz
-                          // Good BPF, good matching, but LCD flickers, refresh rate should be < 20 Hz, reasonable picture.
+                          // Good BPF, good matching, we have some periodical M4 % samples drop.
             return 7'000'000;
 
         default:  // BW capture 2,75Mhz, fs = 8 x 2,75Mhz = 22Mhz max ADC sampling and others.

firmware/application/ui_record_view.cpp

@@ -107,13 +107,14 @@ uint32_t RecordView::set_sampling_rate(uint32_t new_sampling_rate) {
     auto oversample_rate = get_oversample_rate(new_sampling_rate);
     auto actual_sampling_rate = new_sampling_rate * toUType(oversample_rate);
 
-    /* We are changing "REC" icon background to yellow in BW rec Options >600kHz
-     * where we are NOT recording full IQ .C16 files (recorded files are decimated ones).
-     * Those decimated recorded files, has not the full IQ samples.
-     * are ok as recorded spectrum indication, but they should not be used by Replay app.
+    /* We are changing "REC" icon background to yellow in BW rec Options >1Mhz
+     * > 1Mhz BW options , we are NOT recording full IQ .C16 files (those files has some periodical  missing dropped samples).
+     * Those recorded files, has not the full IQ samples information, looks like decimated in file size.
+     * They are ok as recorded spectrum indication, but they should not be used by Replay app. (the voice speed will be accelerated)
 
      * We keep original black background in all the correct IQ .C16 files BW's Options. */
-    if (actual_sampling_rate > 4'800'000) {  // > BW >600kHz  (fs=8*BW), (750kHz...2750kHz)
+    if ((actual_sampling_rate > 8'000'000) || (actual_sampling_rate <= 1'600'000)) {  // yellow REC button means not ok for REC, BW >1Mhz , BW <= 100khz due to NG aliasing.
+        // to be updated or removed in the next PR's, according the achieved extended BW's with good quality bandwith REC limits .
         button_record.set_background(ui::Color::yellow());
     } else {
         button_record.set_background(ui::Color::black());

firmware/baseband/proc_capture.cpp

@@ -27,8 +27,10 @@
 #include "utility.hpp"
 
 CaptureProcessor::CaptureProcessor() {
-    decim_0_4.configure(taps_200k_decim_0.taps, 33554432);
-    decim_0_8.configure(taps_200k_decim_0.taps, 33554432);
+    decim_0_4.configure(taps_200k_decim_0.taps, 33554432);           // to be used with decim1 (/2), then total two stages decim (/8)
+    decim_0_8.configure(taps_200k_decim_0.taps, 33554432);           // to be used with decim1 (/2), then total two stages decim (/16)
+    decim_0_8_180k.configure(taps_180k_wfm_decim_0.taps, 33554432);  // to be used alone - no additional decim1 (/2), then total single stage decim (/8)
+
     decim_1.configure(taps_200k_decim_1.taps, 131072);
 
     channel_spectrum.set_decimation_factor(1);
@@ -37,8 +39,12 @@ CaptureProcessor::CaptureProcessor() {
 
 void CaptureProcessor::execute(const buffer_c8_t& buffer) {
     /* 2.4576MHz, 2048 samples */
-    const auto decim_0_out = decim_0_execute(buffer, dst_buffer);
-    const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
+    const auto decim_0_out = decim_0_execute(buffer, dst_buffer);  // selectable 3 possible decim_0, (/4.  /8 200k soft transition filter , /8 180k sharp )
+
+    const auto decim_1_out = baseband_fs < 4800'000
+                                 ? decim_1.execute(decim_0_out, dst_buffer)  // < 600khz double decim. stage , means 500khz and lower bit rates.
+                                 : decim_0_out;                              // >= 600khz single decim. stage , means 600khz and upper bit rates.
+
     const auto& decimator_out = decim_1_out;
     const auto& channel = decimator_out;
 
@@ -111,8 +117,12 @@ void CaptureProcessor::capture_config(const CaptureConfigMessage& message) {
 
 buffer_c16_t CaptureProcessor::decim_0_execute(const buffer_c8_t& src, const buffer_c16_t& dst) {
     switch (oversample_rate) {
-        case OversampleRate::x8:
-            return decim_0_4.execute(src, dst);
+        case OversampleRate::x8:                     // we can get /8 by two means , decim0 (:4) + decim1 (:2) .  or just decim0 (;8)
+            if (baseband_fs < 4800'000) {            // 600khz (600k x 8)
+                return decim_0_4.execute(src, dst);  // decim_0  /4 with double decim stage
+            } else {
+                return decim_0_8_180k.execute(src, dst);  // decim_0  /8 with single decim stage
+            }
 
         case OversampleRate::x16:
             return decim_0_8.execute(src, dst);

firmware/baseband/proc_capture.hpp

@@ -56,8 +56,9 @@ class CaptureProcessor : public BasebandProcessor {
      * use decim_0_8 for an overall decimation factor of 16. */
     dsp::decimate::FIRC8xR16x24FS4Decim4 decim_0_4{};
     dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0_8{};
-
+    dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0_8_180k{};
     dsp::decimate::FIRC16xR16x16Decim2 decim_1{};
+
     int32_t channel_filter_low_f = 0;
     int32_t channel_filter_high_f = 0;
     int32_t channel_filter_transition = 0;

firmware/common/message.hpp

@@ -815,6 +815,12 @@ enum class OversampleRate : uint8_t {
 
     /* Oversample rate of 32 times the sample rate. */
     x32 = 32,
+
+    /* Oversample rate of 64 times the sample rate. */
+    x64 = 64,
+
+    /* Oversample rate of 128 times the sample rate. */
+    x128 = 128,
 };
 
 class SampleRateConfigMessage : public Message {

firmware/common/oversample.hpp

@@ -46,10 +46,11 @@
  * The oversample rate is used to increase the sample rate to improve SNR and quality.
  * This is also used as the interpolation rate when replaying captures. */
 inline OversampleRate get_oversample_rate(uint32_t sample_rate) {
-    if (sample_rate < 25'000) return OversampleRate::x32;
-    if (sample_rate < 50'000) return OversampleRate::x16;
+    if (sample_rate < 50'000) return OversampleRate::x128;  // 25kk..12k5, prepared for future, OVS ok, but decim. :128 still not implemented.
+    if (sample_rate < 100'000) return OversampleRate::x64;  // 50k, prepared for future, OVS ok, but decim. :64 still not implemented.
+    if (sample_rate < 250'000) return OversampleRate::x16;  // Now tentatively applied to 150k..100k - but as soon as we got decim :32, (150k x16, and 100k x32)
 
-    return OversampleRate::x8;
+    return OversampleRate::x8;  // 250k .. 1Mhz, that decim :8 , is already applied.(OVS and decim OK)
 }
 
 /* Gets the actual sample rate for a given sample rate.