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estimate frequency offset using leader tone

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This commit is contained in:
Ahmet Inan 2024-04-29 07:23:08 +02:00
parent 6f3cea00b2
commit 0a506406f8
1 changed files with 2 additions and 1 deletions
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3
app/src/main/java/xdsopl/robot36/Decoder.java
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@ -208,13 +208,14 @@ public class Decoder {
float postBreakFreq = 0;
for (int i = transitionSamples; i < leaderToneSamples - transitionSamples; ++i)
postBreakFreq += scanLineBuffer[syncPulseIndex + i];
float freqOffset = postBreakFreq / (leaderToneSamples - 2 * transitionSamples);
postBreakFreq = postBreakFreq * halfBandWidth / (leaderToneSamples - 2 * transitionSamples) + centerFreq;
if (postBreakFreq < 1850 || postBreakFreq > 1950)
return false;
Arrays.fill(visCodeBitFreqs, 0);
for (int j = 0; j < 10; ++j)
for (int i = transitionSamples; i < visCodeBitSamples - transitionSamples; ++i)
visCodeBitFreqs[j] += scanLineBuffer[syncPulseIndex + leaderToneSamples + visCodeBitSamples * j + i];
visCodeBitFreqs[j] += scanLineBuffer[syncPulseIndex + leaderToneSamples + visCodeBitSamples * j + i] - freqOffset;
for (int i = 0; i < 10; ++i)
visCodeBitFreqs[i] = visCodeBitFreqs[i] * halfBandWidth / (visCodeBitSamples - 2 * transitionSamples) + centerFreq;
if (visCodeBitFreqs[0] < 1150 || visCodeBitFreqs[0] > 1250 || visCodeBitFreqs[9] < 1150 || visCodeBitFreqs[9] > 1250)