xdsopl/robot36
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Merge 157cd71c33 into 1502f20af1

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marek-o 2025-08-20 10:53:50 +02:00 committed by GitHub
parent 1502f20af1 157cd71c33
commit 41bb8cf81b
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3 changed files with 42 additions and 5 deletions
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20
app/src/main/java/xdsopl/robot36/ColorConverter.java
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@ -6,6 +6,8 @@ Copyright 2024 Ahmet Inan <xdsopl@gmail.com>
package xdsopl.robot36;
import android.graphics.Color;
public final class ColorConverter {
private static int clamp(int value) {
@ -36,6 +38,24 @@ public final class ColorConverter {
return 0xff000000 | (R << 16) | (G << 8) | B;
}
private static int[] argb2components(int argb) {
return new int[] { (argb >> 24) & 0xff, (argb >> 16) & 0xff, (argb >> 8) & 0xff, argb & 0xff };
}
public static int blend(int argbLeft, int argbRight, float ratioOfArgbRight) {
int[] componentsLeft = argb2components(argbLeft);
int[] componentsRight = argb2components(argbRight);
int[] output = new int[4];
ratioOfArgbRight = clamp(ratioOfArgbRight);
for (int i = 0; i < 4; i++) {
output[i] = clamp(Math.round(componentsLeft[i] * (1 - ratioOfArgbRight) + componentsRight[i] * ratioOfArgbRight));
}
return Color.argb(output[0], output[1], output[2], output[3]);
}
public static int GRAY(float level) {
return 0xff000000 | 0x00010101 * compress(level);
}

7
app/src/main/java/xdsopl/robot36/Demodulator.java
View file

@ -33,9 +33,11 @@ public class Demodulator {
public int syncPulseOffset;
public float frequencyOffset;
public static final double syncPulseFrequency = 1200;
public static final double blackFrequency = 1500;
public static final double whiteFrequency = 2300;
Demodulator(int sampleRate) {
double blackFrequency = 1500;
double whiteFrequency = 2300;
double scanLineBandwidth = whiteFrequency - blackFrequency;
frequencyModulation = new FrequencyModulation(scanLineBandwidth, sampleRate);
double syncPulse5msSeconds = 0.005;
@ -65,7 +67,6 @@ public class Demodulator {
baseBandLowPass.taps[i] = (float) (kaiser.window(2.0, i, baseBandLowPass.length) * Filter.lowPass(cutoffFrequency, sampleRate, i, baseBandLowPass.length));
double centerFrequency = (lowestFrequency + highestFrequency) / 2;
baseBandOscillator = new Phasor(-centerFrequency, sampleRate);
double syncPulseFrequency = 1200;
syncPulseFrequencyValue = (float) ((syncPulseFrequency - centerFrequency) * 2 / scanLineBandwidth);
syncPulseFrequencyTolerance = (float) (50 * 2 / scanLineBandwidth);
double syncPorchFrequency = 1500;

20
app/src/main/java/xdsopl/robot36/MainActivity.java
View file

@ -15,6 +15,7 @@ import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
@ -72,6 +73,7 @@ public class MainActivity extends AppCompatActivity {
private ImageView peakMeterView;
private PixelBuffer imageBuffer;
private ShortTimeFourierTransform stft;
private final int binWidthHz = 10;
private short[] shortBuffer;
private float[] recordBuffer;
private AudioRecord audioRecord;
@ -223,8 +225,22 @@ public class MainActivity extends AppCompatActivity {
double lowest = Math.log(1e-9);
double highest = Math.log(1);
double range = highest - lowest;
int lowestBin = 14;
for (int i = 0; i < stride; ++i)
waterfallPlotBuffer.pixels[line + i] = rainbow((Math.log(stft.power[i + 14]) - lowest) / range);
waterfallPlotBuffer.pixels[line + i] = rainbow((Math.log(stft.power[i + lowestBin]) - lowest) / range);
int[] markerFrequencies = new int[] {
(int)Demodulator.syncPulseFrequency,
(int)Demodulator.blackFrequency,
(int)Demodulator.whiteFrequency,
};
for (int freq: markerFrequencies) {
int marker = freq / binWidthHz - lowestBin;
waterfallPlotBuffer.pixels[line + marker - 1] = Color.BLACK;
waterfallPlotBuffer.pixels[line + marker] = ColorConverter.blend(waterfallPlotBuffer.pixels[line + marker], Color.GREEN, 0.8f);
waterfallPlotBuffer.pixels[line + marker + 1] = Color.BLACK;
}
System.arraycopy(waterfallPlotBuffer.pixels, line, waterfallPlotBuffer.pixels, line + stride * (waterfallPlotBuffer.height / 2), stride);
}
}
@ -315,7 +331,7 @@ public class MainActivity extends AppCompatActivity {
if (rateChanged) {
decoder = new Decoder(scopeBuffer, imageBuffer, getString(R.string.raw_mode), recordRate);
decoder.setMode(currentMode);
stft = new ShortTimeFourierTransform(recordRate / 10, 3);
stft = new ShortTimeFourierTransform(recordRate / binWidthHz, 3);
}
startListening();
} else {