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Consolidate anti_alias BW selection into function (#1217)

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Kyle Reed 2023-06-29 22:35:35 -07:00 committed by GitHub
parent 2390d79111
commit 99809c7919
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 39 additions and 92 deletions
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37
firmware/application/apps/capture_app.cpp
View File

@ -60,41 +60,8 @@ CaptureAppView::CaptureAppView(NavigationView& nav)
/* ex. recording 500kHz BW to .C16 file, base_rate clock 500kHz x2(I,Q) x 2 bytes (int signed) =2MB/sec rate SD Card */ /* 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(); waterfall.on_hide();
/* Set up proper anti aliasing BPF bandwith in MAX2837 before ADC sampling according to the new added BW Options . */ /* 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. auto anti_alias_baseband_bandwidth_filter = filter_bandwidth_for_sampling_rate(sampling_rate);
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;
}
record_view.set_sampling_rate(sampling_rate); record_view.set_sampling_rate(sampling_rate);
receiver_model.set_sampling_rate(sampling_rate); receiver_model.set_sampling_rate(sampling_rate);

1
firmware/application/apps/capture_app.hpp
View File

@ -56,7 +56,6 @@ class CaptureAppView : public View {
app_settings::Options::UseGlobalTargetFrequency}; app_settings::Options::UseGlobalTargetFrequency};
uint32_t sampling_rate = 0; uint32_t sampling_rate = 0;
uint32_t anti_alias_baseband_bandwidth_filter = 2500000;
Labels labels{ Labels labels{
{{0 * 8, 1 * 16}, "Rate:", Color::light_grey()}, {{0 * 8, 1 * 16}, "Rate:", Color::light_grey()},

29
firmware/application/apps/ui_level.cpp
View File

@ -205,34 +205,7 @@ size_t LevelView::change_mode(freqman_index_t new_mod) {
receiver_model.set_modulation(ReceiverModel::Mode::Capture); receiver_model.set_modulation(ReceiverModel::Mode::Capture);
field_bw.set_by_value(0); field_bw.set_by_value(0);
field_bw.on_change = [this](size_t, OptionsField::value_t sampling_rate) { field_bw.on_change = [this](size_t, OptionsField::value_t sampling_rate) {
uint32_t anti_alias_baseband_bandwidth_filter = 2500000; auto anti_alias_baseband_bandwidth_filter = filter_bandwidth_for_sampling_rate(sampling_rate);
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_sampling_rate(sampling_rate); receiver_model.set_sampling_rate(sampling_rate);
receiver_model.set_baseband_bandwidth(anti_alias_baseband_bandwidth_filter); receiver_model.set_baseband_bandwidth(anti_alias_baseband_bandwidth_filter);
}; };

29
firmware/application/apps/ui_recon.cpp
View File

@ -1399,34 +1399,7 @@ size_t ReconView::change_mode(freqman_index_t new_mod) {
receiver_model.set_modulation(ReceiverModel::Mode::Capture); receiver_model.set_modulation(ReceiverModel::Mode::Capture);
field_bw.set_by_value(0); field_bw.set_by_value(0);
field_bw.on_change = [this](size_t, OptionsField::value_t sampling_rate) { field_bw.on_change = [this](size_t, OptionsField::value_t sampling_rate) {
uint32_t anti_alias_baseband_bandwidth_filter = 2500000; auto anti_alias_baseband_bandwidth_filter = filter_bandwidth_for_sampling_rate(sampling_rate);
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;
}
record_view->set_sampling_rate(sampling_rate); record_view->set_sampling_rate(sampling_rate);
receiver_model.set_sampling_rate(sampling_rate); receiver_model.set_sampling_rate(sampling_rate);
receiver_model.set_baseband_bandwidth(anti_alias_baseband_bandwidth_filter); receiver_model.set_baseband_bandwidth(anti_alias_baseband_bandwidth_filter);

31
firmware/application/ui/ui_spectrum.cpp
View File

@ -367,4 +367,35 @@ void WaterfallView::on_audio_spectrum() {
} }
} /* namespace spectrum */ } /* namespace spectrum */
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 ... 2000000: // BW Captured range (0 <= 250kHz max) fs = 8 x 250 kHz.
return 1750000; // Minimum BPF MAX2837 for all those lower BW options.
case 4000000 ... 6000000: // 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 2500000; // In some IC, MAX2837 appears as 2250000, but both work similarly.
case 8800000: // BW capture 1,1Mhz fs = 8 x 1,1Mhz = 8,8Mhz. (1Mhz showed slightly higher noise background).
return 3500000;
case 14000000: // 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.
return 5000000;
case 16000000: // BW capture 2Mhz, fs = 8 x 2Mhz = 16Mhz
// Good BPF, good matching, but LCD flickers, refresh rate should be < 20 Hz, reasonable picture.
return 6000000;
case 20000000: // 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.
return 7000000;
default: // BW capture 2,75Mhz, fs = 8 x 2,75Mhz = 22Mhz max ADC sampling and others.
// We tested also 9Mhz FPB slightly too much noise floor, better at 8Mhz.
return 8000000;
}
}
} /* namespace ui */ } /* namespace ui */

4
firmware/application/ui/ui_spectrum.hpp
View File

@ -192,6 +192,10 @@ class WaterfallView : public View {
}; };
} /* namespace spectrum */ } /* namespace spectrum */
/* Calculates the best anti_alias_baseband_bandwidth_filter for the given sampling rate. */
uint32_t filter_bandwidth_for_sampling_rate(int32_t sampling_rate);
} /* namespace ui */ } /* namespace ui */
#endif /*__UI_SPECTRUM_H__*/ #endif /*__UI_SPECTRUM_H__*/