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QpskDemodulator.java
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QpskDemodulator.java
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package ru.r2cloud.jradio.demod;
import java.io.IOException;
import ru.r2cloud.jradio.ByteInput;
import ru.r2cloud.jradio.Context;
import ru.r2cloud.jradio.FloatInput;
import ru.r2cloud.jradio.blocks.Constellation;
import ru.r2cloud.jradio.blocks.ConstellationSoftDecoder;
import ru.r2cloud.jradio.blocks.CostasLoop;
import ru.r2cloud.jradio.blocks.Firdes;
import ru.r2cloud.jradio.blocks.FloatToChar;
import ru.r2cloud.jradio.blocks.PolyphaseClockSyncComplex;
import ru.r2cloud.jradio.blocks.Rail;
import ru.r2cloud.jradio.blocks.RmsAgcComplex;
public class QpskDemodulator implements ByteInput {
private final FloatToChar f2char;
private final Context context;
public QpskDemodulator(FloatInput source, int baudRate, Constellation constel) {
FloatInput next = source;
next = new RmsAgcComplex(source, 1e-2f, 0.5f);
float samplesPerSymbol = next.getContext().getSampleRate() / baudRate;
int nfilts = 16;
float[] rrcTaps = Firdes.rootRaisedCosine(nfilts, nfilts, 1.0f / samplesPerSymbol, 0.5f, (int) (11 * samplesPerSymbol * nfilts));
next = new PolyphaseClockSyncComplex(next, samplesPerSymbol, 0.1f, rrcTaps, nfilts, nfilts / 2, 1.5f, 1);
next = new CostasLoop(next, 0.006f, 4, false);
next = new ConstellationSoftDecoder(next, constel);
next = new Rail(next, -1.0f, 1.0f);
f2char = new FloatToChar(next, 127.0f);
this.context = new Context(this.f2char.getContext());
this.context.setSoftBits(true);
}
@Override
public byte readByte() throws IOException {
return f2char.readByte();
}
@Override
public Context getContext() {
return context;
}
@Override
public void close() throws IOException {
f2char.close();
}
}