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diff --git a/src/main/java/com/jsyn/unitgen/SineOscillatorPhaseModulated.java b/src/main/java/com/jsyn/unitgen/SineOscillatorPhaseModulated.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;
+
+import com.jsyn.ports.UnitInputPort;
+
+/**
+ * Sine oscillator with a phase modulation input. Phase modulation is similar to frequency
+ * modulation but is easier to use in some ways.
+ * 
+ * <pre>
+ * output = sin(PI * (phase + modulation))
+ * </pre>
+ * 
+ * @author Phil Burk (C) 2009 Mobileer Inc
+ */
+public class SineOscillatorPhaseModulated extends SineOscillator {
+    public UnitInputPort modulation;
+
+    /* Define Unit Ports used by connect() and set(). */
+    public SineOscillatorPhaseModulated() {
+        super();
+        addPort(modulation = new UnitInputPort("Modulation"));
+    }
+
+    @Override
+    public void generate(int start, int limit) {
+        double[] frequencies = frequency.getValues();
+        double[] amplitudes = amplitude.getValues();
+        double[] outputs = output.getValues();
+        double[] modulations = modulation.getValues();
+        double currentPhase = phase.getValue();
+
+        for (int i = start; i < limit; i++) {
+            /* Generate sawtooth phaser to provide phase for sine generation. */
+            double phaseIncrement = convertFrequencyToPhaseIncrement(frequencies[i]);
+            currentPhase = incrementWrapPhase(currentPhase, phaseIncrement);
+            double modulatedPhase = currentPhase + modulations[i];
+            double value;
+            if (false) {
+                // TODO Compare benchmarks.
+                while (modulatedPhase >= 1.0) {
+                    modulatedPhase -= 2.0;
+                }
+                while (modulatedPhase < -1.0) {
+                    modulatedPhase += 2.0;
+                }
+                value = fastSin(modulatedPhase);
+            } else {
+                value = Math.sin(modulatedPhase * Math.PI);
+            }
+            outputs[i] = value * amplitudes[i];
+            // System.out.format("Sine: freq = %10.4f , amp = %8.5f, out = %8.5f, phase =  %8.5f, frame =  %8d\n",
+            // frequencies[i], amplitudes[i],outputs[i],currentPhase,frame++ );
+        }
+
+        phase.setValue(currentPhase);
+    }
+
+}