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Ryzerth
2021-04-16 19:53:47 +02:00
parent 098f09844b
commit b16ab3f0c0
9 changed files with 70 additions and 246 deletions
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69
core/src/dsp/resampling.h
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@@ -3,6 +3,7 @@
#include <dsp/window.h>
#include <numeric>
#include <string.h>
#include <dsp/math.h>
namespace dsp {
template <class T>
@@ -192,11 +193,22 @@ namespace dsp {
public:
PowerDecimator() {}
PowerDecimator(stream<complex_t>* in, unsigned int power) { init(in, power); }
PowerDecimator(stream<complex_t>* in, int power, int tapCount) { init(in, power, tapCount); }
void init(stream<complex_t>* in, unsigned int power) {
void init(stream<complex_t>* in, int power, int tapCount) {
_in = in;
_power = power;
_tapCount = tapCount;
// Allocate buffers
for (int i = 0; i < _power; i++) {
buffers[i] = new complex_t[STREAM_BUFFER_SIZE / (i+1)];
bufferStart[i] = &buffers[i][_tapCount - 1];
}
// Create taps
genHalfbandTaps();
generic_block<PowerDecimator>::registerInput(_in);
generic_block<PowerDecimator>::registerOutput(&out);
}
@@ -220,29 +232,6 @@ namespace dsp {
int run() {
int count = _in->read();
if (count < 0) { return -1; }
if (_power == 0) {
memcpy(out.writeBuf, _in->readBuf, count * sizeof(complex_t));
}
else if (_power == 1) {
for (int j = 0; j < count; j += 2) {
out.writeBuf[j / 2].re = (_in->readBuf[j].re + _in->readBuf[j + 1].re) * 0.5f;
out.writeBuf[j / 2].im = (_in->readBuf[j].im + _in->readBuf[j + 1].im) * 0.5f;
}
count /= 2;
}
_in->flush();
if (_power > 1) {
for (int i = 1; i < _power; i++) {
for (int j = 0; j < count; j += 2) {
out.writeBuf[j / 2].re = (_in->readBuf[j].re + _in->readBuf[j + 1].re) * 0.5f;
out.writeBuf[j / 2].im = (_in->readBuf[j].im + _in->readBuf[j + 1].im) * 0.5f;
}
count /= 2;
}
}
if (!out.swap(count)) { return -1; }
return count;
@@ -250,10 +239,36 @@ namespace dsp {
stream<complex_t> out;
private:
unsigned int _power = 0;
void genHalfbandTaps() {
if (taps != NULL) { delete[] taps; }
taps = new float[_tapCount];
// Using Blackman-harris windows
int half = _tapCount / 2;
for (int i = 0; i < _tapCount; i++) {
taps[i] = sinc((FL_M_PI / 2.0f) * (i-half)) * blackmanHarrisWin(i, _tapCount - 1);
printf("%f\n", taps[i]);
}
}
inline float sinc(float x) {
return ((x == 0) ? 1.0f : (sinf(x)/x)) / FL_M_PI;
}
inline float blackmanHarrisWin(float n, float N) {
return 0.35875f - (0.48829f*cosf(2.0f*FL_M_PI*(n/N))) + (0.14128f*cosf(4.0f*FL_M_PI*(n/N))) - (0.01168f*cosf(6.0f*FL_M_PI*(n/N)));
}
int _power = 0;
int _tapCount = 31;
stream<complex_t>* _in;
// Buffer lists, sets max decimation to 2^32
complex_t* buffers[32];
complex_t* bufferStart[32];
float* taps = NULL;
};
}