diff --git a/app/src/main/java/xdsopl/robot36/Delay.java b/app/src/main/java/xdsopl/robot36/Delay.java
new file mode 100644
index 0000000..7aec0a0
--- /dev/null
+++ b/app/src/main/java/xdsopl/robot36/Delay.java
@@ -0,0 +1,27 @@
+/*
+Digital delay line
+
+Copyright 2024 Ahmet Inan <xdsopl@gmail.com>
+*/
+
+package xdsopl.robot36;
+
+public class Delay {
+	public final int length;
+	private final float[] buf;
+	private int pos;
+
+	Delay(int length) {
+		this.length = length;
+		this.buf = new float[length];
+		this.pos = 0;
+	}
+
+	float push(float input) {
+		float tmp = buf[pos];
+		buf[pos] = input;
+		if (++pos >= length)
+			pos = 0;
+		return tmp;
+	}
+}
diff --git a/app/src/main/java/xdsopl/robot36/MainActivity.java b/app/src/main/java/xdsopl/robot36/MainActivity.java
index 3a4042d..b2d7293 100644
--- a/app/src/main/java/xdsopl/robot36/MainActivity.java
+++ b/app/src/main/java/xdsopl/robot36/MainActivity.java
@@ -37,6 +37,7 @@ public class MainActivity extends AppCompatActivity {
 	private float[] recordBuffer;
 	private AudioRecord audioRecord;
 	private TextView status;
+	private Delay powerDelay;
 	private SimpleMovingAverage powerAvg;
 	private ComplexMovingAverage syncAvg;
 	private Phasor osc_1200;
@@ -62,7 +63,7 @@ public class MainActivity extends AppCompatActivity {
 
 	private void processSamples() {
 		for (float v : recordBuffer) {
-			sad = syncAvg.avg(sad.set(v).mul(osc_1200.rotate()));
+			sad = syncAvg.avg(sad.set(powerDelay.push(v)).mul(osc_1200.rotate()));
 			float level = sad.norm() / powerAvg.avg(v * v);
 			int x = Math.min((int) (scopeWidth * level), scopeWidth);
 			for (int i = 0; i < x; ++i)
@@ -79,8 +80,9 @@ public class MainActivity extends AppCompatActivity {
 
 	private void initTools(int sampleRate) {
 		double powerWindowSeconds = 0.5;
-		int powerWindowSamples = (int) Math.round(powerWindowSeconds * sampleRate);
+		int powerWindowSamples = (int) Math.round(powerWindowSeconds * sampleRate) | 1;
 		powerAvg = new SimpleMovingAverage(powerWindowSamples);
+		powerDelay = new Delay((powerWindowSamples - 1) / 2);
 		double syncPulseSeconds = 0.009;
 		int syncPulseSamples = (int) Math.round(syncPulseSeconds * sampleRate);
 		syncAvg = new ComplexMovingAverage(syncPulseSamples);