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replaced sma with a sinc filter

pull/11/head
Ahmet Inan 2024-04-22 16:12:37 +02:00
rodzic 085fa2a408
commit e52c2ee3ef
1 zmienionych plików z 8 dodań i 4 usunięć
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app/src/main/java/xdsopl/robot36/Demodulator.java
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@ -12,7 +12,7 @@ public class Demodulator {
private final ComplexMovingAverage syncPulse9msFilter;
private final ComplexMovingAverage syncPulse20msFilter;
private final ComplexMovingAverage scanLineFilter;
private final ComplexMovingAverage baseBandLowPass;
private final ComplexConvolution baseBandLowPass;
private final FrequencyModulation scanLineDemod;
private final SchmittTrigger syncPulseTrigger;
private final Phasor syncPulseOscillator;
@ -71,8 +71,12 @@ public class Demodulator {
float lowestFrequency = 1100;
float highestFrequency = 2300;
float cutoffFrequency = (highestFrequency - lowestFrequency) / 2;
int lowPassSamples = (int) Math.round(0.443 * sampleRate / cutoffFrequency) | 1;
baseBandLowPass = new ComplexMovingAverage(lowPassSamples);
double baseBandLowPassSeconds = 0.002;
int baseBandLowPassSamples = (int) Math.round(baseBandLowPassSeconds * sampleRate) | 1;
baseBandLowPass = new ComplexConvolution(baseBandLowPassSamples);
Kaiser kaiser = new Kaiser();
for (int i = 0; i < baseBandLowPass.length; ++i)
baseBandLowPass.taps[i] = (float) (kaiser.window(2.0, i, baseBandLowPass.length) * Filter.lowPass(cutoffFrequency, i, baseBandLowPass.length));
float centerFrequency = (lowestFrequency + highestFrequency) / 2;
baseBandOscillator = new Phasor(-centerFrequency, sampleRate);
float syncPulseFrequency = 1200;
@ -97,7 +101,7 @@ public class Demodulator {
public boolean process(float[] buffer) {
boolean syncPulseDetected = false;
for (int i = 0; i < buffer.length; ++i) {
baseBand = baseBandLowPass.avg(baseBand.set(buffer[i]).mul(baseBandOscillator.rotate()));
baseBand = baseBandLowPass.push(baseBand.set(buffer[i]).mul(baseBandOscillator.rotate()));
syncPulse = syncPulse.set(baseBand).mul(syncPulseOscillator.rotate());
syncPulse5ms = syncPulse5msFilter.avg(syncPulse5ms.set(syncPulse));
syncPulse9ms = syncPulse9msFilter.avg(syncPulse9ms.set(syncPulse));