plectrum

Plectrum: instrument tuner for Android
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ScaledHammingWindow.java (1187B)

      1 /*
      2 *      _______                       _____   _____ _____  
      3 *     |__   __|                     |  __ \ / ____|  __ \ 
      4 *        | | __ _ _ __ ___  ___  ___| |  | | (___ | |__) |
      5 *        | |/ _` | '__/ __|/ _ \/ __| |  | |\___ \|  ___/ 
      6 *        | | (_| | |  \__ \ (_) \__ \ |__| |____) | |     
      7 *        |_|\__,_|_|  |___/\___/|___/_____/|_____/|_|     
      8 *                                                         
      9 * -------------------------------------------------------------
     10 *
     11 * TarsosDSP is developed by Joren Six at IPEM, University Ghent
     12 *  
     13 * -------------------------------------------------------------
     14 *
     15 *  Info: http://0110.be/tag/TarsosDSP
     16 *  Github: https://github.com/JorenSix/TarsosDSP
     17 *  Releases: http://0110.be/releases/TarsosDSP/
     18 *  
     19 *  TarsosDSP includes modified source code by various authors,
     20 *  for credits and info, see README.
     21 * 
     22 */
     23 
     24 package be.tarsos.dsp.util.fft;
     25 
     26 public class ScaledHammingWindow extends WindowFunction {
     27 
     28 	@Override
     29 	protected float value(int length, int index) {
     30 		double scale = 1.0 / (double)length / 0.54;
     31 		double factor = TWO_PI / (double)length;
     32 		return (float) (scale * (25.0/46.0 - 21.0/46.0 * Math.cos(factor * index)));
     33 	}
     34 
     35 }