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Oversample (#1336)

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* WIP Oversample cleanup

* WIP

* WIP

* WIP dynamic interpolation

* WIP cleanup

* Fix math errors

* Add some optional assertions

* Add support for x32 interpolation

* Update proc_replay.cpp

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Kyle Reed 2023-08-02 12:59:26 -07:00 • committed by GitHub
parent e2ad0a1b1a
commit 37386c29cb
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37
firmware/application/ui/ui_spectrum.cpp
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@ -380,33 +380,34 @@ void WaterfallView::on_audio_spectrum() {
} /* namespace 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 ... 2000000: // BW Captured range (0 <= 250kHz max) fs = 8 x 250 kHz.
return 1750000; // Minimum BPF MAX2837 for all those lower BW options.
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.
return 1'750'000; // 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 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 8800000: // BW capture 1,1Mhz fs = 8 x 1,1Mhz = 8,8Mhz. (1Mhz showed slightly higher noise background).
return 3500000;
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 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 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.
return 5'000'000;
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 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.
return 6'000'000;
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;
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.
return 7'000'000;
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;
return 8'000'000;
}
}