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diff --git a/apps/OboeTester/app/src/main/cpp/synth/SquareOscillatorDPW.h b/apps/OboeTester/app/src/main/cpp/synth/SquareOscillatorDPW.h
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+++ b/apps/OboeTester/app/src/main/cpp/synth/SquareOscillatorDPW.h
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+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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.
+ *
+ * This code was translated from the JSyn Java code.
+ * JSyn is Copyright 2009 Phil Burk, Mobileer Inc
+ * JSyn is licensed under the Apache License, Version 2.0
+ */
+
+#ifndef SYNTHMARK_SQUARE_OSCILLATOR_DPW_H
+#define SYNTHMARK_SQUARE_OSCILLATOR_DPW_H
+
+#include <cstdint>
+#include <math.h>
+#include "SynthTools.h"
+#include "DifferentiatedParabola.h"
+
+namespace marksynth {
+/**
+ * Square waves contains the odd partials of a fundamental.
+ * The square wave is generated by combining two sawtooth waveforms
+ * that are 180 degrees out of phase. This causes the even partials
+ * to be cancelled out.
+ */
+class SquareOscillatorDPW : public SawtoothOscillator
+{
+public:
+    SquareOscillatorDPW()
+    : SawtoothOscillator()
+    , dpw1()
+    , dpw2() {}
+
+    virtual ~SquareOscillatorDPW() = default;
+
+    virtual inline synth_float_t translatePhase(synth_float_t phase1,
+            synth_float_t phaseIncrement) {
+        synth_float_t val1 = dpw1.next(phase1, phaseIncrement);
+
+        /* Generate second sawtooth so we can add them together. */
+        synth_float_t phase2 = phase1 + 1.0; /* 180 degrees out of phase. */
+        if (phase2 >= 1.0)
+            phase2 -= 2.0;
+        synth_float_t val2 = dpw1.next(phase2, phaseIncrement);
+
+        /*
+         * Need to adjust amplitude based on positive phaseInc. little less than half at
+         * Nyquist/2.0!
+         */
+        const synth_float_t STARTAMP = 0.92; // derived empirically
+        synth_float_t positivePhaseIncrement = (phaseIncrement < 0.0)
+                ? phaseIncrement
+                : 0.0 - phaseIncrement;
+        synth_float_t scale = STARTAMP - positivePhaseIncrement;
+        return scale * (val1 - val2);
+    }
+
+private:
+    DifferentiatedParabola dpw1;
+    DifferentiatedParabola dpw2;
+};
+};
+#endif // SYNTHMARK_SQUARE_OSCILLATOR_DPW_H