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Support for 1.25MHz capture (#1418)

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* Advanced draft decim /4 just waterfall ok

* apply some Kall's corrections + formatting

* Tidy up both decim_factors

* New refine optimizations

* Format issues

* more format issues ...mmmm

* comments update

* WIP Cleanup

* WIP

* WIP - add variant

* Use std::visit to dispatch MultiDecimator -- fluent API

* Clean up comments

* Merge next and fix compilation

* Fix odd loop in BlockDecimator

* Clean up spectrum math

* Descibe spectrum update math better, more clear math.

* Apply spectrum interval correction at 1.5M

* Increase replay buffer to handle x4 ovs

---------

Co-authored-by: Brumi-2021 <ea3hqj@gmail.com>
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Kyle Reed 2023-08-29 10:26:38 -07:00 • committed by GitHub
parent e7e1bedcad
commit de81156223
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11 changed files with 170 additions and 189 deletions
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22
firmware/application/ui/ui_spectrum.cpp
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@ -383,33 +383,33 @@ 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 ... 3'500'000: // BW Captured range (0 <= 250kHz max) fs = 8x250 kHz =2000., 16x150 khz =2400, 32x100 khz =3200, (32x75k = 2400), (future 64x40 khz =2400)
case 0 ... 3'500'000: // BW Captured range (0 <= 250kHz max) fs = 8x250k = 2000, 16x150k = 2400, 32x100k = 3200, 32x75k = 2400, (future 64x40 khz = 2400)
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
case 4'000'000 ... 7'000'000: // OVS x8, BW capture range (500k...750kHz max) fs_max = 8 x 750k = 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 8'000'000: // 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 7'000'001 ... 10'000'000: // OVS x8 and x4, 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. writing 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.
case 12'000'000 ... 14'000'000: // OVS x4, BW capture 3Mhz, fs = 4 x 3Mhz = 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
case 16'000'000: // OVS x4, BW capture 4Mhz, fs = 4 x 4Mhz = 16Mhz
// Good BPF, good matching, we have some periodical M4 % samples drop.
return 5'000'000;
return 5'500'000;
case 16'000'000: // BW capture 2Mhz, fs = 8 x 2Mhz = 16Mhz
case 18'000'000: // OVS x4, BW capture 4,5Mhz, fs = 4 x 4,5Mhz = 18Mhz
// 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
case 20'000'000: // OVS x4, BW capture 5Mhz, fs = 4 x 5Mhz = 20Mhz
// 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.
default: // BW capture 5,5Mhz, fs = 4 x 5,5Mhz = 22Mhz max ADC sampling and others.
// We tested also 9Mhz FPB slightly too much noise floor, better at 8Mhz.
return 8'000'000;
}