.gitmodules

@@ -1,7 +1,3 @@
 [submodule "third-party/c-flags"]
 	path = third-party/c-flags
 	url = https://github.com/DieTime/c-flags.git
-[submodule "third-party/cxxopts"]
-	path = third-party/cxxopts
-	url = https://github.com/jarro2783/cxxopts.git
-	branch = v3.2.1

CMakeLists.txt

@@ -1,15 +1,10 @@
 cmake_minimum_required(VERSION 3.12)
 
-project(pico-radio)
+project(pico-radio C)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-include_directories(include
+include_directories(include /opt/picoscope/include third-party/c-flags/single-header)
-  /opt/picoscope/include
-  third-party/c-flags/single-header
-  third-party/cxxopts/include)
-  
 link_directories(/opt/picoscope/lib)
 
 add_subdirectory(src/recorder)
-add_subdirectory(src/filter)

include/filter/filter/filter.hpp

@@ -1,21 +0,0 @@
-#ifndef FILTER_IFILTER_H
-#define FILTER_IFILTER_H
-
-#include <cstdint>
-#include <vector>
-
-namespace Filter {
-
-class IFilter {
- protected:
-  std::vector<float> impulseResponse;
-
- public:
-  IFilter(std::size_t size);
-  virtual ~IFilter(){};
-
-  void ConvolveIQ(const std::vector<float>& input, std::vector<float>& output);
-};
-} // namespace Filter
-
-#endif

include/filter/filter/low_pass_filter.hpp

@@ -1,18 +0,0 @@
-#ifndef FILTER_LOW_PASS_FILTER_H
-#define FILTER_LOW_PASS_FILTER_H
-
-#include <vector>
-
-#include <filter/filter/filter.hpp>
-#include <filter/window/window.hpp>
-
-namespace Filter {
-
-class LowPassFilter : public IFilter {
- public:
-  LowPassFilter(std::size_t size, std::size_t cutoffHz, std::size_t sampleRateHz, const std::vector<float>& window);
-  ~LowPassFilter() override{};
-};
-} // namespace Filter
-
-#endif

include/filter/window/hamming_window.hpp

@@ -1,21 +0,0 @@
-#ifndef FILTER_HAMMING_WINDOW_H
-#define FILTER_HAMMING_WINDOW_H
-
-#include <cstddef>
-#include <vector>
-#include <filter/window/window.hpp>
-
-namespace Filter {
-class HammingWindow : public IWindow {
- private:
-  std::vector<float> window;
-
- public:
-  HammingWindow(std::size_t width);
-
-  ~HammingWindow() override {}
-  const std::vector<float>& getWindow() override { return window; }
-};
-} // namespace Filter
-
-#endif

include/filter/window/window.hpp

@@ -1,14 +0,0 @@
-#ifndef FILTER_IWINDOW_H
-#define FILTER_IWINDOW_H
-
-#include <vector>
-
-namespace Filter {
-class IWindow {
- public:
-  virtual ~IWindow() {}
-  virtual const std::vector<float>& getWindow() = 0;
-};
-} // namespace Filter
-
-#endif

src/filter/CMakeLists.txt

@@ -1,7 +0,0 @@
-file(GLOB_RECURSE SOURCES "./*.cpp")
-add_executable(filter ${SOURCES})
-target_compile_options(filter PRIVATE -Wall -Wextra)
-set_target_properties(filter PROPERTIES
-    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
-    CXX_STANDARD 20
-)

src/filter/filter/filter.cpp

@@ -1,31 +0,0 @@
-#include <cstddef>
-#include <vector>
-
-#include <filter/filter/filter.hpp>
-
-namespace Filter {
-IFilter::IFilter(std::size_t size) {
-  impulseResponse.reserve(size);
-}
-
-void IFilter::ConvolveIQ(const std::vector<float>& input, std::vector<float>& output) {
-  // TODO: SIMD
-
-  auto itIn = input.begin();
-  auto itOut = output.begin();
-
-  while (itIn != input.end()) {
-    for (float h : impulseResponse) {
-      // I
-      *itOut += *itIn * h;
-      itIn++;
-      itOut++;
-
-      // Q
-      *itOut += *itIn * h;
-      itIn++;
-      itOut++;
-    }
-  }
-}
-} // namespace Filter

src/filter/filter/low_pass_filter.cpp

@@ -1,22 +0,0 @@
-#include <cmath>
-#include <numbers>
-#include <vector>
-
-#include <filter/filter/low_pass_filter.hpp>
-
-namespace Filter {
-LowPassFilter::LowPassFilter(std::size_t size, std::size_t cutoffHz, std::size_t sampleRateHz, const std::vector<float>& window) : IFilter(size) {
-  for (std::size_t i = 0; i < size; i++) {
-    std::size_t shift = std::round(size / 2);
-    float sampleTime = 1.0f / sampleRateHz;
-    if (shift != i) {
-      IFilter::impulseResponse[i] = std::sin(2.0f * std::numbers::pi * sampleTime * (i - shift)) / (std::numbers::pi * sampleTime * (i - shift));
-    } else {
-      IFilter::impulseResponse[i] = 2.0f * cutoffHz;
-    }
-
-    IFilter::impulseResponse[i] *= sampleTime * window[i];
-  }
-}
-
-} // namespace Filter

src/filter/main.cpp

@@ -1,69 +0,0 @@
-#include <cstdio>
-#include <cstring>
-#include <iostream>
-#include <vector>
-
-#include <filter/filter/low_pass_filter.hpp>
-#include <filter/window/hamming_window.hpp>
-
-#include <cxxopts.hpp>
-
-const std::size_t BUFFER_SIZE = 256;
-
-using namespace Filter;
-
-int main(int argc, char** argv) {
-  // parse arguments
-  cxxopts::Options options("filter", "filter signals; stdin->stdout");
-  options.add_options()("c,cutoff", "Cutoff frequency in Hz.", cxxopts::value<size_t>()->no_implicit_value())("s,sample_rate", "Sample rate of input in Hz.",
-                                                                                                              cxxopts::value<size_t>()->no_implicit_value());
-
-  cxxopts::ParseResult result;
-  try {
-    result = options.parse(argc, argv);
-  } catch (cxxopts::exceptions::exception e) {
-    std::cerr << e.what() << std::endl;
-    return -1;
-  }
-
-  if (result.count("cutoff") + result.count("sample_rate") != 2) {
-    std::cerr << options.help() << std::endl;
-    return -1;
-  }
-
-  // prepare pipes for binary data
-  std::freopen(nullptr, "rb", stdin);
-  if (std::ferror(stdin)) {
-    std::cerr << "Failed to reopen stdin: " << std::strerror(errno) << std::endl;
-    return errno;
-  }
-
-  std::freopen(nullptr, "wb", stdout);
-  if (std::ferror(stdout)) {
-    std::cerr << "Failed to reopen stdout: " << std::strerror(errno) << std::endl;
-    return errno;
-  }
-
-  // create low pass filter
-  LowPassFilter lpf(BUFFER_SIZE, result["cutoff"].as<std::size_t>(), result["sample_rate"].as<std::size_t>(), HammingWindow(BUFFER_SIZE).getWindow());
-
-  // read data
-  std::vector<float> inputBuffer;
-  inputBuffer.reserve(BUFFER_SIZE);
-
-  std::vector<float> outputBuffer;
-  outputBuffer.reserve(BUFFER_SIZE);
-
-  std::size_t len;
-
-  while ((len = std::fread(inputBuffer.data(), sizeof(inputBuffer[0]), BUFFER_SIZE, stdin)) > 0) {
-    if (std::ferror(stdin) && !std::feof(stdin)) {
-      std::cerr << "Failed to read from stdin: " << std::strerror(errno) << std::endl;
-      return errno;
-    }
-
-    lpf.ConvolveIQ(inputBuffer, outputBuffer);
-  }
-
-  return 0;
-}

src/filter/window/hamming_window.cpp

@@ -1,13 +0,0 @@
-#include <cmath>
-#include <numbers>
-
-#include <filter/window/hamming_window.hpp>
-
-namespace Filter {
-HammingWindow::HammingWindow(std::size_t width) {
-  window.reserve(width);
-  for (std::size_t i = 0; i < width; i++) {
-    window[i] = (25 / 46.0) - (21 / 46.0) * std::cos(2 * std::numbers::pi * i / width);
-  }
-}
-} // namespace Filter

third-party/cxxopts

@@ -1 +0,0 @@
-Subproject commit 4bf61f08697b110d9e3991864650a405b3dd515d