我在c＃中遇到FFT问题

Question

微软是否有可以使用的良好FFT？

所以我做了欠自己的FFT，它起作用了一些情况，但现在全部......

就像我得到它一样  f（t）= 10 * sin（2 * pi * 3000 * t）+ 20 * sin（1000 * 2 * PI * t） 它会工作，但如果我补充 + 5 *罪（2 * pi * 100 * T）开始表演有趣吗？

现在在Matlab中它运行良好但不在我的关闭中，而且我的fft似乎只在图像中返回正确的数字而不是真正的...

这是我的代码：

enter code here



public struct polar1
    {
        public double real;
        public double img;

    };
   private float Fs;
   private int N;
   private polar1 [] F;
   private int R;
   public DSPclass(float[] DSP1,int f1)
    {
        N = DSP1.Length;
        R = DSP1.Length;
       F = new polar1[N];
       Fs = (float)f1;

    }

public void FFT1(float[] DSP1)
   {
     polar1[] x = new polar1[DSP1.Length];
    for (int v = 0; v < N; v++)
       {
           x[v].real = DSP1[v];
           x[v].img = 0;
       } 

      F = FFT(x);
      int temp;
    }

   public polar1[] FFT(polar1[] x)
   {
       int N2 = x.Length;
       polar1[] X = new polar1[N2];
       if (N2 == 1)
       {
           return x;
       }
       polar1[] odd = new polar1[N2 / 2];
       polar1[] even = new polar1[N2 / 2];
       polar1[] Y_Odd = new polar1[N2 / 2];
       polar1[] Y_Even = new polar1[N2 / 2];


       for (int t = 0; t < N2 / 2; t++)
       {
           even[t].img = x[t * 2].img;
           even[t].real = x[t * 2].real;
           odd[t].img = x[(t * 2) + 1].img;
           odd[t].real = x[(t * 2) + 1].real;
       }
       Y_Even = FFT(even);
       Y_Odd = FFT(odd);
       polar1 temp4;

       for (int k = 0; k < (N2 / 2); k++)
       {
           temp4 = Complex1(k, N2);
           X[k].real = Y_Even[k].real + (Y_Odd[k].real * temp4.real);
           X[k + (N2 / 2)].real = Y_Even[k].real - (Y_Odd[k].real * temp4.real);  
           X[k].img = Y_Even[k].img + (Y_Odd[k].real * temp4.img);
            X[k + (N2 / 2)].img = Y_Even[k].img - (Y_Odd[k].real * temp4.img);
           }

       return X;
   }

 public double magnitude( polar1 temp)
    {
        double tempD;
        tempD = Math.Sqrt ( (temp.img * temp.img) + (temp.real * temp.real));
        return tempD;

    }

    public polar1 Complex2(int K, int N, int F3)
    {
        polar1 temp;
        double temp1;
        temp1 = (2D * K *F3) / N;
        if (temp1 % 2 == 0 || temp1 == 0)
        {
            temp.real = 1D;
            temp.img = 0D;

        }
        else if ((temp1 - 1) % 2 == 0)
        {
            temp.real = -1D;
            temp.img = 0D;
        }
        else if ((temp1 / .5D) - 1 % 2 == 0)
        {
            if ((temp1 - .5D) % 2 == 0)
            {
                temp.real = 0D;
                temp.img = -1D;
            }
            else
            {
                temp.real = 0D;
                temp.img = 1D;
            }
        }
        else
        {
            temp.real = Math.Cos(temp1 * Math.PI);
            temp.img = -1D * Math.Sin(temp1 * Math.PI);
        }


        return temp;

    }
    public polar1 Complex1(int K, int N3)
    {
       polar1 temp;
        double temp1;
        temp1 = (2D * Math.PI *K) / N3;
                temp.real =  Math.Cos(temp1);
                temp.img =  Math.Sin(temp1);
        return temp;

    }

    public int Apm(double[] img, double[] real)
    {

        for (int i = 0; i < R; i++)
        {
        img[i] = F[i].img;
        real[i] = F[i].real;
        }

        return R;
    }


    public int frequencies(float [] freq, float [] Ctemp)
    {
        bool flag = false;
        bool flagD = false;
        float tempOld = 0;
        float tempNew =0;
        int tempc = 0;
        int counter = 0;
        for (int i = 0; i < R; i++)
                {
                    if (((i / N) * Fs) >= (Fs / 2))
                    {
                        return counter;
                    }
            if ((int)F[i].img != 0 )
                {
                flag = true;
                tempOld = (float)(Math.Abs(F[i].img));
                }
            else
                {
                if (flagD == true)
                {
                    freq[counter] = ((float)tempc / (float)N) * Fs;
                    Ctemp[counter] = tempNew; //magnitude(F[tempc]);
                    counter++;
                    flagD = false;
                }
                flag = false;
                tempOld = 0;
                tempNew = 0;
                }
            if(flag == true)
                {
                if (tempOld > tempNew)
                {
                    tempNew = tempOld;
                    tempc = i;
                    flagD = true;
                }
                }
                }
        return counter;  
    }

}