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updating_comments (#2191)

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Brumi-2021 2024-07-08 11:11:12 +02:00 committed by GitHub
parent 032168234a
commit 9ef58b7763
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4 changed files with 7 additions and 12 deletions
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2
firmware/application/apps/ui_mictx.cpp
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@ -285,7 +285,7 @@ void MicTXView::set_rxbw_defaults(bool use_app_settings) { // Initially in that
field_rxbw.set_by_value(0);
} else if ((mic_mod_index == MIC_MOD_USB) | (mic_mod_index == MIC_MOD_LSB)) {
field_bw.set_value(3); // In SSB by default let's limit TX_BW to 3kHz.
field_bw.set_range(2, 3); // User range to modify that TX_BW. (TODO pending to investigate 4khz).
field_bw.set_range(2, 3); // User TXBW GUI range to modify that SSB TX_BW to limit SSB radiated spectrum.
field_bw.set_step(1);
}
// field_bw is hidden in other modulation cases

4
firmware/baseband/dsp_hilbert.cpp
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@ -33,11 +33,11 @@ HilbertTransform::HilbertTransform() {
}
void HilbertTransform::execute(float in, float& out_i, float& out_q) {
// Synthesized Hilbert Transform, it is implemented based on 1/2 band LPF and later freq shift fs/4, achieving a H.T_BW of transmitted = fs/2 ;
// Half_band LPF means a LP filter with f_cut_off = fs/4; Half band = Half max band = 1/2 * fs_max = 1/2 x f_Nyquist = 1/2 * fs/2 = fs/4
float a = 0, b = 0;
float in_filtered = sos_input.execute(in) * 1.0f; // Anti-aliasing LPF at fs/4 mic audio filter front-end.
// it is exactly matching with the usefull mic BW_cut_off =fs/4 of the following Hilbert Transf. implementation
// Ex. to TX SSB 3khz BW (3KHZ =fs/4) ,we need to run Hiblert_Trf fs = 12khz . And our anti-aliasing filter is also fcut =fs/4 when we use a half_band_LPF .
switch (n) {
case 0:

11
firmware/baseband/dsp_modulate.cpp
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@ -84,18 +84,13 @@ SSB::SSB()
void SSB::set_fs_div_factor(float new_bw_ssb) {
switch ((int)new_bw_ssb / 1000) {
case 2:
fs_div_factor = 192; // TXBW_ssb = 2khz = fs/4 ; fs of Hilbert Transform => 8khz fs Hilbert = 1536.000/8000= 192
fs_div_factor = 192; // TXBW_ssb = 2khz = BW_cut_off LPF = fs/4 ; BW_HT fs Hilbert Transform (4khz=fs/2) ==> (8k=fs) Hilbert_fs = 1.536.000/8000= 192
break;
case 3:
fs_div_factor = 128; // TXBW_ssb = 3khz = fs/4 ; fs of Hilbert Transform => 12khz fs Hilbert = 1536.000/12000= 128
fs_div_factor = 128; // TXBW_ssb = 3khz = BW_cut_off LPF = fs/4 ; BW_HT fs Hilbert Transform (6khz=fs/2) ==> (12k=fs) Hilbert_fs = 1.536.000/12000= 128
break;
/* TODO pending to investigate 4khz, now is making aliasing folding with audio sweep .
case 4:
fs_div_factor = 96; // TXBW_ssb = 4khz = fs/4 ; fs of Hilbert Transform => 16khz fs Hilbert = 1536.000/16000= 96
break;
*/
default:
fs_div_factor = 128; // TXBW_ssb = 3khz = fs/4 ; fs of Hilbert Transform => 12khz fs Hilbert = 1536.000/12000= 128
fs_div_factor = 128; // TXBW_ssb = 3khz = BW_cut_off LPF = fs/4 ; BW_HT fs Hilbert Transform (6khz=fs/2) ==> (12k=fs) Hilbert_fs = 1.536.000/12000= 128
break;
}
}

2
firmware/baseband/proc_mictx.cpp
View File

@ -144,7 +144,7 @@ void MicTXProcessor::on_message(const Message* const msg) {
modulator->set_mode(dsp::modulate::Mode::DSB);
}
modulator->set_over(baseband_fs / 24000); // Keep no change.
modulator->set_over(baseband_fs / 24000); // "over" is calculated based on relationship fs_transceiver / fs_audio_mic_capture, to be used in dsp_modulate.cpp
am_enabled = config_message.am_enabled;
usb_enabled = config_message.usb_enabled;