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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.engine.MultiTable;
/**
* Band-limited square wave oscillator. This requires more CPU than a SquareOscillator but is less
* noisy at high frequencies.
*
* @author Phil Burk (C) 2009 Mobileer Inc
*/
public class SquareOscillatorBL extends SawtoothOscillatorBL {
@Override
protected double generateBL(MultiTable multiTable, double currentPhase,
double positivePhaseIncrement, double flevel, int i) {
double val1 = multiTable.calculateSawtooth(currentPhase, positivePhaseIncrement, flevel);
/* Generate second sawtooth so we can add them together. */
double phase2 = currentPhase + 1.0; /* 180 degrees out of phase. */
if (phase2 >= 1.0) {
phase2 -= 2.0;
}
double val2 = multiTable.calculateSawtooth(phase2, positivePhaseIncrement, flevel);
/*
* Need to adjust amplitude based on positive phaseInc. little less than half at
* Nyquist/2.0!
*/
final double STARTAMP = 0.92; /* Derived by viewing waveforms with TJ_SEEOSC */
double scale = STARTAMP - positivePhaseIncrement;
return scale * (val1 - val2);
}
}
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