1 | package com.synthbot.jasiohost;
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2 |
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3 | public class myDFT {
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4 | private float sampleRate;
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5 |
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6 | private static float sinTime[];
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7 | private static float cosTime[];
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8 | private int N;
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9 | private float freq;
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10 |
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11 | public myDFT(float sampleRa,float freq, int N)
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12 | {
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13 | this.sampleRate = 44100;
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14 | this.N = 512;
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15 | this.freq = 440;
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16 | sinTime = new float[N];
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17 | cosTime = new float[N];
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18 | sinTime = createSinTimeSeries(this.N, this.freq);
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19 | cosTime = createCosTimeSeries(this.N, this.freq);
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20 | }
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21 | public float findFreq (float[] x, int minfreq, int maxfreq, int stepfreq)
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22 | {
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23 | float real = 0;
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24 | float imag = 0;
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25 | float toreturn=0;
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26 | float powerAtFreq = 0;
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27 | float MaxpowerAtFreq = 0;
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28 | float[] samples = new float[this.N];
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29 | for (int a = minfreq; a < maxfreq; a += stepfreq)
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30 | {
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31 | sinTime = createSinTimeSeries(this.N, a);
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32 | cosTime = createCosTimeSeries(this.N, a);
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33 | for(int bb = 0; bb < this.N; bb++)
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34 | {
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35 | real += x[bb] * sinTime[bb];
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36 | imag += x[bb] * cosTime[bb];
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37 |
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38 | }
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39 | powerAtFreq = (real * real) + (imag * imag);
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40 |
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41 | if (powerAtFreq > MaxpowerAtFreq)
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42 | {
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43 | MaxpowerAtFreq = powerAtFreq;
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44 | toreturn = a;
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45 | }
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46 | }
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47 | return toreturn;
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48 |
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49 | }
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50 | public float[] inverseDFt(float[] real, float[] imag)
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51 | {
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52 | float[] samples = new float[this.N];
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53 |
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54 | for (int a = 0; a < this.N; a++)
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55 | {
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56 |
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57 | }
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58 | return samples;
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59 | }
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60 | public float calculateMyDFT(float[] x)
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61 | {
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62 | float real = 0;
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63 | float imag = 0;
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64 |
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65 | float powerAtFreq = 0;
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66 |
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67 | for(int a = 0; a < this.N; a++)
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68 | {
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69 | real += x[a] * sinTime[a];
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70 | imag += x[a] * cosTime[a];
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71 | }
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72 | powerAtFreq = (real * real) + (imag * imag);
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73 | return powerAtFreq;
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74 | //System.out.println("Power at freq " + freq + " is " + powerAtFreq);
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75 | }
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76 |
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77 | public float[] createSinTimeSeries(int N, float freq)
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78 | {
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79 | float output[] = new float[N];
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80 | for (int i = 0; i < N; i++) {
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81 | output[i] = (float) (Math.sin(2 * Math.PI * i * freq / this.sampleRate));
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82 | }
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83 | return output;
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84 |
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85 | }
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86 | public float[] createCosTimeSeries(int N, float freq)
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87 | {
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88 | float output[] = new float[N];
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89 | for (int i = 0; i < N; i++) {
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90 | output[i] = (float) (Math.cos(2 * Math.PI * i * freq / this.sampleRate));
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91 | }
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92 | return output;
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93 | }
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94 | }
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