/**
* Copyright 2004-2006 DFKI GmbH.
* All Rights Reserved. Use is subject to license terms.
*
* This file is part of MARY TTS.
*
* MARY TTS is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package marytts.signalproc.window;
import marytts.signalproc.display.FunctionGraph;
import marytts.signalproc.display.LogSpectrum;
import marytts.util.math.MathUtils;
/**
* @author Marc Schröder
*
* Implements a Blackman window
*
*/
public class BlackmanWindow extends Window {
public BlackmanWindow(int length) {
super(length);
}
public BlackmanWindow(int length, double prescalingFactor) {
super(length, prescalingFactor);
}
protected void initialise() {
boolean prescale = (prescalingFactor != 1.);
for (int i = 0; i < window.length; i++) {
window[i] = 0.42 - 0.5 * Math.cos(i * 2 * Math.PI / (window.length - 1)) + 0.08
* Math.cos(i * 4 * Math.PI / (window.length - 1));
if (prescale)
window[i] *= prescalingFactor;
}
}
public String toString() {
return "Blackman window";
}
public static void main(String[] args) {
int samplingRate = Integer.getInteger("samplingrate", 1).intValue();
int windowLengthMs = Integer.getInteger("windowlength.ms", 0).intValue();
int windowLength = Integer.getInteger("windowlength.samples", 512).intValue();
// If both are given, use window length in milliseconds:
if (windowLengthMs != 0)
windowLength = windowLengthMs * samplingRate / 1000;
int fftSize = Math.max(4096, MathUtils.closestPowerOfTwoAbove(windowLength));
Window w = new BlackmanWindow(windowLength);
FunctionGraph timeGraph = new FunctionGraph(0, 1. / samplingRate, w.window);
timeGraph.showInJFrame(w.toString() + " in time domain", true, false);
double[] fftSignal = new double[fftSize];
// fftSignal should integrate to one, so normalise amplitudes:
double sum = MathUtils.sum(w.window);
for (int i = 0; i < w.window.length; i++) {
fftSignal[i] = w.window[i] / sum;
}
LogSpectrum freqGraph = new LogSpectrum(fftSignal, samplingRate);
freqGraph.showInJFrame(w.toString() + " log frequency response", true, false);
}
}