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remove FFTW stuff

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using a simple FFT algorithm instead
This commit is contained in:
Georgi Gerganov
2020-11-28 09:40:46 +02:00
parent 3e62f89c53
commit 8c5752567c
6 changed files with 123 additions and 93 deletions
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178
main.cpp
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@@ -3,7 +3,6 @@
* \author Georgi Gerganov
*/
#include "fftw3.h"
#include "reed-solomon/rs.hpp"
#include <SDL2/SDL.h>
@@ -17,6 +16,7 @@
#include <ctime>
#include <algorithm>
#include <map>
#include <complex>
#ifndef M_PI
#define M_PI 3.14159265358979323846f
@@ -48,57 +48,126 @@ struct DataRxTx;
static DataRxTx *g_data = nullptr;
namespace {
//constexpr float IRAND_MAX = 1.0f/RAND_MAX;
//inline float frand() { return ((float)(rand()%RAND_MAX)*IRAND_MAX); }
constexpr double kBaseSampleRate = 48000.0;
constexpr auto kMaxSamplesPerFrame = 1024;
constexpr auto kMaxDataBits = 256;
constexpr auto kMaxDataSize = 256;
constexpr auto kMaxLength = 140;
constexpr auto kMaxSpectrumHistory = 4;
constexpr auto kMaxRecordedFrames = 64*10;
constexpr auto kDefaultFixedLength = 82;
constexpr double kBaseSampleRate = 48000.0;
constexpr auto kMaxSamplesPerFrame = 1024;
constexpr auto kMaxDataBits = 256;
constexpr auto kMaxDataSize = 256;
constexpr auto kMaxLength = 140;
constexpr auto kMaxSpectrumHistory = 4;
constexpr auto kMaxRecordedFrames = 64*10;
constexpr auto kDefaultFixedLength = 82;
enum TxMode {
FixedLength = 0,
VariableLength,
};
// FFT routines taken from https://stackoverflow.com/a/37729648/4039976
using AmplitudeData = std::array<float, kMaxSamplesPerFrame>;
using AmplitudeData16 = std::array<int16_t, kMaxRecordedFrames*kMaxSamplesPerFrame>;
using SpectrumData = std::array<float, kMaxSamplesPerFrame>;
using RecordedData = std::array<float, kMaxRecordedFrames*kMaxSamplesPerFrame>;
int log2(int N) {
int k = N, i = 0;
while(k) {
k >>= 1;
i++;
}
return i - 1;
}
inline void addAmplitudeSmooth(const AmplitudeData & src, AmplitudeData & dst, float scalar, int startId, int finalId, int cycleMod, int nPerCycle) {
int nTotal = nPerCycle*finalId;
float frac = 0.15f;
float ds = frac*nTotal;
float ids = 1.0f/ds;
int nBegin = frac*nTotal;
int nEnd = (1.0f - frac)*nTotal;
for (int i = startId; i < finalId; i++) {
float k = cycleMod*finalId + i;
if (k < nBegin) {
dst[i] += scalar*src[i]*(k*ids);
} else if (k > nEnd) {
dst[i] += scalar*src[i]*(((float)(nTotal) - k)*ids);
} else {
dst[i] += scalar*src[i];
int check(int n) {
return n > 0 && (n & (n - 1)) == 0;
}
int reverse(int N, int n) {
int j, p = 0;
for(j = 1; j <= log2(N); j++) {
if(n & (1 << (log2(N) - j)))
p |= 1 << (j - 1);
}
return p;
}
void ordina(std::complex<float>* f1, int N) {
std::complex<float> f2[kMaxSamplesPerFrame];
for(int i = 0; i < N; i++)
f2[i] = f1[reverse(N, i)];
for(int j = 0; j < N; j++)
f1[j] = f2[j];
}
void transform(std::complex<float>* f, int N) {
ordina(f, N); //first: reverse order
std::complex<float> *W;
W = (std::complex<float> *)malloc(N / 2 * sizeof(std::complex<float>));
W[1] = std::polar(1., -2. * M_PI / N);
W[0] = 1;
for(int i = 2; i < N / 2; i++)
W[i] = pow(W[1], i);
int n = 1;
int a = N / 2;
for(int j = 0; j < log2(N); j++) {
for(int i = 0; i < N; i++) {
if(!(i & n)) {
std::complex<float> temp = f[i];
std::complex<float> Temp = W[(i * a) % (n * a)] * f[i + n];
f[i] = temp + Temp;
f[i + n] = temp - Temp;
}
}
n *= 2;
a = a / 2;
}
free(W);
}
template <class T>
float getTime_ms(const T & tStart, const T & tEnd) {
return ((float)(std::chrono::duration_cast<std::chrono::microseconds>(tEnd - tStart).count()))/1000.0;
void FFT(std::complex<float>* f, int N, float d) {
transform(f, N);
for(int i = 0; i < N; i++)
f[i] *= d; //multiplying by step
}
void FFT(float * src, std::complex<float>* dst, int N, float d) {
for (int i = 0; i < N; ++i) {
dst[i].real(src[i]);
dst[i].imag(0);
}
FFT(dst, N, d);
}
enum TxMode {
FixedLength = 0,
VariableLength,
};
using AmplitudeData = std::array<float, kMaxSamplesPerFrame>;
using AmplitudeData16 = std::array<int16_t, kMaxRecordedFrames*kMaxSamplesPerFrame>;
using SpectrumData = std::array<float, kMaxSamplesPerFrame>;
using RecordedData = std::array<float, kMaxRecordedFrames*kMaxSamplesPerFrame>;
inline void addAmplitudeSmooth(const AmplitudeData & src, AmplitudeData & dst, float scalar, int startId, int finalId, int cycleMod, int nPerCycle) {
int nTotal = nPerCycle*finalId;
float frac = 0.15f;
float ds = frac*nTotal;
float ids = 1.0f/ds;
int nBegin = frac*nTotal;
int nEnd = (1.0f - frac)*nTotal;
for (int i = startId; i < finalId; i++) {
float k = cycleMod*finalId + i;
if (k < nBegin) {
dst[i] += scalar*src[i]*(k*ids);
} else if (k > nEnd) {
dst[i] += scalar*src[i]*(((float)(nTotal) - k)*ids);
} else {
dst[i] += scalar*src[i];
}
int getECCBytesForLength(int len) {
return std::max(4, 2*(len/5));
}
}
template <class T>
float getTime_ms(const T & tStart, const T & tEnd) {
return ((float)(std::chrono::duration_cast<std::chrono::microseconds>(tEnd - tStart).count()))/1000.0;
}
int getECCBytesForLength(int len) {
return std::max(4, 2*(len/5));
}
}
struct DataRxTx {
DataRxTx(int aSampleRateOut, int aSampleRate, int aSamplesPerFrame, int aSampleSizeB, const char * text) {
sampleSizeBytes = aSampleSizeB;
@@ -213,17 +282,9 @@ struct DataRxTx {
rxData.fill(0);
if (fftPlan) fftwf_destroy_plan(fftPlan);
if (fftIn) fftwf_free(fftIn);
if (fftOut) fftwf_free(fftOut);
fftIn = (float*) fftwf_malloc(sizeof(float)*samplesPerFrame);
fftOut = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex)*samplesPerFrame);
fftPlan = fftwf_plan_dft_r2c_1d(1*samplesPerFrame, fftIn, fftOut, FFTW_ESTIMATE);
for (int i = 0; i < samplesPerFrame; ++i) {
fftOut[i][0] = 0.0f;
fftOut[i][1] = 0.0f;
fftOut[i].real(0.0f);
fftOut[i].imag(0.0f);
}
}
@@ -391,13 +452,13 @@ struct DataRxTx {
}
// calculate spectrum
std::copy(sampleAmplitudeAverage.begin(), sampleAmplitudeAverage.begin() + samplesPerFrame, fftIn);
std::copy(sampleAmplitudeAverage.begin(), sampleAmplitudeAverage.begin() + samplesPerFrame, fftIn.data());
fftwf_execute(fftPlan);
FFT(fftIn.data(), fftOut.data(), samplesPerFrame, 1.0);
double fsum = 0.0;
for (int i = 0; i < samplesPerFrame; ++i) {
sampleSpectrum[i] = (fftOut[i][0]*fftOut[i][0] + fftOut[i][1]*fftOut[i][1]);
sampleSpectrum[i] = (fftOut[i].real()*fftOut[i].real() + fftOut[i].imag()*fftOut[i].imag());
fsum += sampleSpectrum[i];
}
for (int i = 1; i < samplesPerFrame/2; ++i) {
@@ -448,7 +509,7 @@ struct DataRxTx {
std::copy(
recordedAmplitude.begin() + offsetTx*step,
recordedAmplitude.begin() + offsetTx*step + samplesPerFrame, fftIn);
recordedAmplitude.begin() + offsetTx*step + samplesPerFrame, fftIn.data());
for (int k = 1; k < framesPerTx-1; ++k) {
for (int i = 0; i < samplesPerFrame; ++i) {
@@ -456,10 +517,10 @@ struct DataRxTx {
}
}
fftwf_execute(fftPlan);
FFT(fftIn.data(), fftOut.data(), samplesPerFrame, 1.0);
for (int i = 0; i < samplesPerFrame; ++i) {
sampleSpectrum[i] = (fftOut[i][0]*fftOut[i][0] + fftOut[i][1]*fftOut[i][1]);
sampleSpectrum[i] = (fftOut[i].real()*fftOut[i].real() + fftOut[i].imag()*fftOut[i].imag());
}
for (int i = 1; i < samplesPerFrame/2; ++i) {
sampleSpectrum[i] += sampleSpectrum[samplesPerFrame - i];
@@ -638,9 +699,8 @@ struct DataRxTx {
bool receivingData;
bool analyzingData;
fftwf_plan fftPlan = 0;
float *fftIn;
fftwf_complex *fftOut = 0;
std::array<float, kMaxSamplesPerFrame> fftIn;
std::array<std::complex<float>, kMaxSamplesPerFrame> fftOut;
::AmplitudeData sampleAmplitude;
::SpectrumData sampleSpectrum;