From 14484b550aa01e715fda4036610adf3f749ca65e Mon Sep 17 00:00:00 2001 From: Brumi-2021 <86470699+Brumi-2021@users.noreply.github.com> Date: Sun, 21 Nov 2021 19:35:31 +0100 Subject: [PATCH] Increase more BW Options to Capture App PR to increase the BW Options in the Capture App , beyond the current max, 500khz. (from 600Khz till 2,75Mhz) all of them work well into the screen, but only <= 600Khz BW are correctly saved into SD Card with full captured data. (Onwards, >600Khz optiions, at the moment , the created SD card file has decimated data, due - to SD Card writting speed limitations),- but I feel still quite interesting feature to keep them. --- firmware/application/apps/capture_app.cpp | 47 +++++++++++++++++++++-- firmware/application/apps/capture_app.hpp | 11 +++++- 2 files changed, 53 insertions(+), 5 deletions(-) diff --git a/firmware/application/apps/capture_app.cpp b/firmware/application/apps/capture_app.cpp index a0965d2d..e86fca8b 100644 --- a/firmware/application/apps/capture_app.cpp +++ b/firmware/application/apps/capture_app.cpp @@ -74,17 +74,58 @@ CaptureAppView::CaptureAppView(NavigationView& nav) { option_bandwidth.on_change = [this](size_t, uint32_t base_rate) { sampling_rate = 8 * base_rate; // Decimation by 8 done on baseband side - + /* base_rate is used for FFT calculation and display LCD, and also in recording writing SD Card rate. */ + /* ex. sampling_rate values, 4Mhz, when recording 500 khz (BW) and fs 8 Mhz , when selected 1 Mhz BW ...*/ + /* ex. recording 500khz BW to .C16 file, base_rate clock 500khz x2(I,Q) x 2 bytes (int signed) =2MB/sec rate SD Card */ + waterfall.on_hide(); record_view.set_sampling_rate(sampling_rate); receiver_model.set_sampling_rate(sampling_rate); + /* Set up proper anti aliasing BPF bandwith in MAX2837 before ADC sampling according to the new added BW Options . */ + + switch(sampling_rate) { // we use the var fs (sampling_rate) , to set up BPF aprox < fs_max/2 by Nyquist theorem. + + case 0 ... 2000000: // BW Captured range (0 <= 250Khz max ) fs = 8 x 250 Khz + anti_alias_baseband_bandwidth_filter = 1750000; // Minimum BPF MAX2837 for all those lower BW options. + break; + + case 4000000 ... 6000000: // BW capture range (500k ... 750Khz max ) fs_max = 8 x 750Khz = 6Mhz + // BW 500k ... 750khz , ex. 500khz (fs = 8*BW = 4Mhz) , BW 600Khz (fs = 4,8Mhz) , BW 750 Khz (fs = 6Mhz) + anti_alias_baseband_bandwidth_filter = 2500000; // in some IC MAX2837 appear 2250000 , but both works similar. + break; + + case 8800000: // BW capture 1,1Mhz fs = 8 x 1,1Mhz = 8,8Mhz . (1Mhz showed slightly higher noise background). + anti_alias_baseband_bandwidth_filter = 3500000; + break; + + case 14000000: // BW capture 1,75Mhz , fs = 8 x 1,75Mhz = 14Mhz + // good BPF ,good matching, but LCD making flicker , refresh rate should be < 20 Hz , but reasonable picture + anti_alias_baseband_bandwidth_filter = 5000000; + break; + + case 16000000: // BW capture 2Mhz , fs = 8 x 2Mhz = 16Mhz + // good BPF ,good matching, but LCD making flicker , refresh rate should be < 20 Hz , but reasonable picture + anti_alias_baseband_bandwidth_filter = 6000000; + break; + + case 20000000: // BW capture 2,5Mhz , fs= 8 x 2,5 Mhz = 20Mhz + // good BPF ,good matching, but LCD making flicker , refresh rate should be < 20 Hz , but reasonable picture + anti_alias_baseband_bandwidth_filter = 7000000; + break; + + default: // BW capture 2,75Mhz, fs = 8 x 2,75Mhz= 22Mhz max ADC sampling) and others. + // We tested also 9Mhz FPB stightly too much noise floor , better 8Mhz + anti_alias_baseband_bandwidth_filter = 8000000; + } + receiver_model.set_baseband_bandwidth(anti_alias_baseband_bandwidth_filter); + + waterfall.on_show(); }; - option_bandwidth.set_selected_index(7); // 500k + option_bandwidth.set_selected_index(7); // 500k, Preselected starting default option 500khz receiver_model.set_modulation(ReceiverModel::Mode::Capture); - receiver_model.set_baseband_bandwidth(baseband_bandwidth); receiver_model.enable(); record_view.on_error = [&nav](std::string message) { diff --git a/firmware/application/apps/capture_app.hpp b/firmware/application/apps/capture_app.hpp index 944b048c..c23c3b74 100644 --- a/firmware/application/apps/capture_app.hpp +++ b/firmware/application/apps/capture_app.hpp @@ -48,7 +48,7 @@ private: static constexpr ui::Dim header_height = 3 * 16; uint32_t sampling_rate = 0; - static constexpr uint32_t baseband_bandwidth = 2500000; + uint32_t anti_alias_baseband_bandwidth_filter = 2500000; // we rename the previous var , and change type static constexpr to normal var. void on_tuning_frequency_changed(rf::Frequency f); @@ -95,7 +95,14 @@ private: { " 50k ", 50000 }, { "100k ", 100000 }, { "250k ", 250000 }, - { "500k ", 500000 } + { "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) + { "750k ", 750000 }, // From that BW onwards, the LCD is ok, but the recorded file is auto decimated,(not real file size) + { "1100k", 1100000 }, + { "1750k", 1750000 }, + { "2000k", 2000000 }, + { "2500k", 2500000 }, + { "2750k", 2750000 } // That is our max Capture option , to keep using later / 8 decimation (22Mhz sampling ADC) } };