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bugfix + preparations for stereo FM

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Ryzerth
2021-07-22 23:30:41 +02:00
parent 2baf607b8c
commit 175e361ccd
8 changed files with 381 additions and 14 deletions
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108
core/src/dsp/window.h
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@@ -11,6 +11,12 @@ namespace dsp {
virtual void createTaps(float* taps, int tapCount, float factor = 1.0f) {}
};
class generic_complex_window {
public:
virtual int getTapCount() { return -1; }
virtual void createTaps(dsp::complex_t* taps, int tapCount, float factor = 1.0f) {}
};
class BlackmanWindow : public filter_window::generic_window {
public:
BlackmanWindow() {}
@@ -76,6 +82,108 @@ namespace dsp {
float _cutoff, _transWidth, _sampleRate;
};
class BandPassBlackmanWindow : public filter_window::generic_complex_window {
public:
BandPassBlackmanWindow() {}
BandPassBlackmanWindow(float lowCutoff, float highCutoff, float transWidth, float sampleRate) { init(lowCutoff, highCutoff, transWidth, sampleRate); }
void init(float lowCutoff, float highCutoff, float transWidth, float sampleRate) {
assert(lowCutoff <= highCutoff);
_lowCutoff = lowCutoff;
_highCutoff = highCutoff;
_transWidth = transWidth;
_sampleRate = sampleRate;
// Calculate other values
_offset = (_lowCutoff + _highCutoff) / 2.0f;
_cutoff = fabs((_highCutoff - _lowCutoff) / 2.0f);
}
void setSampleRate(float sampleRate) {
_sampleRate = sampleRate;
}
void setCutoffs(float lowCutoff, float highCutoff) {
assert(lowCutoff <= highCutoff);
_lowCutoff = lowCutoff;
_highCutoff = highCutoff;
// Calculate other values
_offset = (_lowCutoff + _highCutoff) / 2.0f;
_cutoff = fabs((_highCutoff - _lowCutoff) / 2.0f);
}
void setLowCutoff(float lowCutoff) {
assert(lowCutoff <= _highCutoff);
_lowCutoff = lowCutoff;
// Calculate other values
_offset = (_lowCutoff + _highCutoff) / 2.0f;
_cutoff = fabs((_highCutoff - _lowCutoff) / 2.0f);
}
void setHighCutoff(float highCutoff) {
assert(_lowCutoff <= highCutoff);
_highCutoff = highCutoff;
// Calculate other values
_offset = (_lowCutoff + _highCutoff) / 2.0f;
_cutoff = fabs((_highCutoff - _lowCutoff) / 2.0f);
}
void setTransWidth(float transWidth) {
_transWidth = transWidth;
}
int getTapCount() {
float fc = _cutoff / _sampleRate;
if (fc > 1.0f) {
fc = 1.0f;
}
int _M = 4.0f / (_transWidth / _sampleRate);
if (_M < 4) {
_M = 4;
}
if (_M % 2 == 0) { _M++; }
return _M;
}
void createTaps(dsp::complex_t* taps, int tapCount, float factor = 1.0f) {
// Calculate cuttoff frequency
float omega = 2.0f * FL_M_PI * (_cutoff / _sampleRate);
if (omega > FL_M_PI) { omega = FL_M_PI; }
// Generate taps
float val;
float sum = 0.0f;
float tc = tapCount;
for (int i = 0; i < tapCount; i++) {
val = math::sinc(omega, (float)i - (tc/2), FL_M_PI) * window_function::blackman(i, tc - 1);
taps[i].re = val;
taps[i].im = 0;
sum += val;
}
// Normalize taps and multiply by supplied factor
for (int i = 0; i < tapCount; i++) {
taps[i] = taps[i] * factor;
taps[i] = taps[i] / sum;
}
// Add offset
lv_32fc_t phase = lv_cmake(1.0f, 0.0f);
lv_32fc_t phaseDelta = lv_cmake(std::cos((-_offset / _sampleRate) * 2.0f * FL_M_PI), std::sin((-_offset / _sampleRate) * 2.0f * FL_M_PI));
volk_32fc_s32fc_x2_rotator_32fc((lv_32fc_t*)taps, (lv_32fc_t*)taps, phaseDelta, &phase, tapCount);
}
private:
float _lowCutoff, _highCutoff;
float _cutoff, _transWidth, _sampleRate, _offset;
};
}
class RRCTaps : public filter_window::generic_window {