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Oversample capturing for low bandwidths (#1332)

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* draft_low_bit_rate_solution_Capture_App

* second_draft_dynamic_decim

* Add support for Oversample Rate to capture.

---------

Co-authored-by: Brumi-2021 <ea3hqj@gmail.com>
This commit is contained in:
Kyle Reed
2023-07-31 08:46:07 -07:00
committed by GitHub
parent a24b3ad3de
commit d24ff7b3bc
10 changed files with 132 additions and 43 deletions
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42
firmware/baseband/proc_capture.cpp
View File

@@ -27,7 +27,8 @@
#include "utility.hpp"
CaptureProcessor::CaptureProcessor() {
decim_0.configure(taps_200k_decim_0.taps, 33554432);
decim_0_4.configure(taps_200k_decim_0.taps, 33554432);
decim_0_8.configure(taps_200k_decim_0.taps, 33554432);
decim_1.configure(taps_200k_decim_1.taps, 131072);
channel_spectrum.set_decimation_factor(1);
@@ -36,7 +37,7 @@ CaptureProcessor::CaptureProcessor() {
void CaptureProcessor::execute(const buffer_c8_t& buffer) {
/* 2.4576MHz, 2048 samples */
const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
const auto decim_0_out = decim_0_execute(buffer, dst_buffer);
const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
const auto& decimator_out = decim_1_out;
const auto& channel = decimator_out;
@@ -65,9 +66,19 @@ void CaptureProcessor::on_message(const Message* const message) {
channel_spectrum.on_message(message);
break;
case Message::ID::SamplerateConfig:
samplerate_config(*reinterpret_cast<const SamplerateConfigMessage*>(message));
case Message::ID::SamplerateConfig: {
auto config = reinterpret_cast<const SamplerateConfigMessage*>(message);
baseband_fs = config->sample_rate;
update_for_rate_change();
break;
}
case Message::ID::OversampleRateConfig: {
auto config = reinterpret_cast<const OversampleRateConfigMessage*>(message);
oversample_rate = config->oversample_rate;
update_for_rate_change();
break;
}
case Message::ID::CaptureConfig:
capture_config(*reinterpret_cast<const CaptureConfigMessage*>(message));
@@ -78,11 +89,14 @@ void CaptureProcessor::on_message(const Message* const message) {
}
}
void CaptureProcessor::samplerate_config(const SamplerateConfigMessage& message) {
baseband_fs = message.sample_rate;
void CaptureProcessor::update_for_rate_change() {
baseband_thread.set_sampling_rate(baseband_fs);
size_t decim_0_output_fs = baseband_fs / decim_0.decimation_factor;
auto decim_0_factor = oversample_rate == OversampleRate::Rate8x
? decim_0_4.decimation_factor
: decim_0_8.decimation_factor;
size_t decim_0_output_fs = baseband_fs / decim_0_factor;
size_t decim_1_input_fs = decim_0_output_fs;
size_t decim_1_output_fs = decim_1_input_fs / decim_1.decimation_factor;
@@ -103,6 +117,20 @@ void CaptureProcessor::capture_config(const CaptureConfigMessage& message) {
}
}
buffer_c16_t CaptureProcessor::decim_0_execute(const buffer_c8_t& src, const buffer_c16_t& dst) {
switch (oversample_rate) {
case OversampleRate::Rate8x:
return decim_0_4.execute(src, dst);
case OversampleRate::Rate16x:
return decim_0_8.execute(src, dst);
default:
chDbgPanic("Unhandled OversampleRate");
return {};
}
}
int main() {
EventDispatcher event_dispatcher{std::make_unique<CaptureProcessor>()};
event_dispatcher.run();

15
firmware/baseband/proc_capture.hpp
View File

@@ -50,7 +50,13 @@ class CaptureProcessor : public BasebandProcessor {
dst.data(),
dst.size()};
dsp::decimate::FIRC8xR16x24FS4Decim4 decim_0{};
/* NB: There are two decimation passes: 0 and 1. In pass 0, one of
* the following will be selected based on the oversample rate.
* use decim_0_4 for an overall decimation factor of 8.
* use decim_0_8 for an overall decimation factor of 16. */
dsp::decimate::FIRC8xR16x24FS4Decim4 decim_0_4{};
dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0_8{};
dsp::decimate::FIRC16xR16x16Decim2 decim_1{};
int32_t channel_filter_low_f = 0;
int32_t channel_filter_high_f = 0;
@@ -61,14 +67,19 @@ class CaptureProcessor : public BasebandProcessor {
SpectrumCollector channel_spectrum{};
size_t spectrum_interval_samples = 0;
size_t spectrum_samples = 0;
OversampleRate oversample_rate{OversampleRate::Rate8x};
/* NB: Threads should be the last members in the class definition. */
BasebandThread baseband_thread{
baseband_fs, this, baseband::Direction::Receive, /*auto_start*/ false};
RSSIThread rssi_thread{};
void samplerate_config(const SamplerateConfigMessage& message);
/* Called to update members when the sample rate or oversample rate is changed. */
void update_for_rate_change();
void capture_config(const CaptureConfigMessage& message);
/* Dispatch to the correct decim_0 based on oversample rate. */
buffer_c16_t decim_0_execute(const buffer_c8_t& src, const buffer_c16_t& dst);
};
#endif /*__PROC_CAPTURE_HPP__*/