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diff --git a/src/main/java/com/jsyn/unitgen/ImpulseOscillator.java b/src/main/java/com/jsyn/unitgen/ImpulseOscillator.java
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+++ b/src/main/java/com/jsyn/unitgen/ImpulseOscillator.java
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+/*
+ * Copyright 2009 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.unitgen;
+
+/**
+ * Narrow impulse oscillator. An impulse is only one sample wide. It is useful for pinging filters
+ * or generating an "impulse response".
+ * 
+ * @author Phil Burk (C) 2009 Mobileer Inc
+ */
+public class ImpulseOscillator extends UnitOscillator {
+
+    @Override
+    public void generate(int start, int limit) {
+        double[] frequencies = frequency.getValues();
+        double[] amplitudes = amplitude.getValues();
+        double[] outputs = output.getValues();
+
+        // Variables have a single value.
+        double currentPhase = phase.getValue();
+
+        double inverseNyquist = synthesisEngine.getInverseNyquist();
+
+        for (int i = start; i < limit; i++) {
+            /* Generate sawtooth phasor to provide phase for impulse generation. */
+            double phaseIncrement = frequencies[i] * inverseNyquist;
+            currentPhase += phaseIncrement;
+
+            double ampl = amplitudes[i];
+            double result = 0.0;
+            if (currentPhase >= 1.0) {
+                currentPhase -= 2.0;
+                result = ampl;
+            } else if (currentPhase < -1.0) {
+                currentPhase += 2.0;
+                result = ampl;
+            }
+            outputs[i] = result;
+        }
+
+        // Value needs to be saved for next time.
+        phase.setValue(currentPhase);
+    }
+
+}