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Some DC-Spike removal magic..

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Pay no attention to the spike behind the curtain.. <*|:-)
This commit is contained in:
Charles J. Cliffe
2015-10-21 19:50:53 -04:00
parent fcbe2723e6
commit 5fd4ba8059
4 changed files with 50 additions and 4 deletions
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src/process/SpectrumVisualProcessor.cpp
+42
View File
@@ -8,6 +8,7 @@ SpectrumVisualProcessor::SpectrumVisualProcessor() : lastInputBandwidth(0), last
fftSize.store(0);
centerFreq.store(0);
bandwidth.store(0);
hideDC.store(false);
freqShifter = nco_crcf_create(LIQUID_NCO);
shiftFrequency = 0;
@@ -95,6 +96,11 @@ void SpectrumVisualProcessor::setup(int fftSize_in) {
busy_run.unlock();
}
void SpectrumVisualProcessor::setHideDC(bool hideDC) {
this->hideDC.store(hideDC);
}
void SpectrumVisualProcessor::process() {
if (!isOutputEmpty()) {
return;
@@ -306,6 +312,42 @@ void SpectrumVisualProcessor::process() {
output->spectrum_points[i * 2] = ((float) i / (float) iMax);
output->spectrum_points[i * 2 + 1] = v;
}
if (hideDC.load()) { // DC-spike removal
long long freqMin = centerFreq-(bandwidth/2);
long long freqMax = centerFreq+(bandwidth/2);
long long zeroPt = (iqData->frequency-freqMin);
if (freqMin < iqData->frequency && freqMax > iqData->frequency) {
int freqRange = int(freqMax-freqMin);
int freqStep = freqRange/fftSize;
int fftStart = (zeroPt/freqStep)-(2000/freqStep);
int fftEnd = (zeroPt/freqStep)+(2000/freqStep);
// std::cout << "range:" << freqRange << ", step: " << freqStep << ", start: " << fftStart << ", end: " << fftEnd << std::endl;
if (fftEnd-fftStart < 2) {
fftEnd++;
fftStart--;
}
int numSteps = (fftEnd-fftStart);
int halfWay = fftStart+(numSteps/2);
if ((fftEnd+numSteps/2+1 < fftSize) && (fftStart-numSteps/2-1 >= 0) && (fftEnd > fftStart)) {
int n = 1;
for (int i = fftStart; i < halfWay; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftStart - n) * 2 + 1];
n++;
}
n = 1;
for (int i = halfWay; i < fftEnd; i++) {
output->spectrum_points[i * 2 + 1] = output->spectrum_points[(fftEnd + n) * 2 + 1];
n++;
}
}
}
}
output->fft_ceiling = fft_ceil_maa;
output->fft_floor = fft_floor_maa;
src/process/SpectrumVisualProcessor.h
+2
View File
@@ -33,6 +33,7 @@ public:
int getDesiredInputSize();
void setup(int fftSize);
void setHideDC(bool hideDC);
protected:
void process();
@@ -68,4 +69,5 @@ private:
std::vector<liquid_float_complex> resampleBuffer;
std::atomic_int desiredInputSize;
std::mutex busy_run;
std::atomic_bool hideDC;
};