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Plotting Fast Fourier Transform in C#
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C#3.0
C#
Hi there,


I'm final year student of electronics engineering i build a software with takes input from serial port and plots it. i'm done with this part, the thing that bugging me is that i want to plot Fast Fourier Transform of that data. over the internet i cannot find any implementation of FFT in C# or i cannot understand the implementation if anyone will sort me out i will glad thanks in advance...

<pre lang="c#">
//My serial port receiving code
string _myData;

_myData = serialPort1.ReadExisting();
// i want to plot That _myData string in FFT

Regards
Sajid
Posted
Add a Solution

4 solutions

Quote:
public class FFT
{
public static Boolean IsPowerOfTwo(UInt32 x)
{
return ((x != 0) && (x & (x - 1)) == 0);
}
public static UInt32 NextPowerOfTwo(UInt32 x)
{
x = x - 1;
x = x | (x >> 1);
x = x | (x >> 2);
x = x | (x >> 4);
x = x | (x >> 8);
x = x | (x >> 16);
return x + 1;
}
public static UInt32 NumberOfBitsNeeded(UInt32 PowerOfTwo)
{
if (PowerOfTwo > 0)
{
for (UInt32 i = 0, mask = 1; ; i++, mask <<= 1)
{
if ((PowerOfTwo & mask) != 0)
return i;
}
}
return 0; // error
}
public static UInt32 ReverseBits(UInt32 index, UInt32 NumBits)
{
UInt32 i, rev;

for (i = rev = 0; i < NumBits; i++)
{
rev = (rev << 1) | (index & 1);
index >>= 1;
}

return rev;
}
public struct Complex
{
public double Re, Im;
public Complex(double x, double y)
{
this.Re = x; this.Im = y;
}
public Complex Mul(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re * C2.Re - this.Im * C2.Im;
aux.Im = this.Re * C2.Im + this.Im * C2.Re;
return aux;
}
public Complex Add(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re + C2.Re;
aux.Im = this.Im + C2.Im;
return aux;
}
public Complex Sub(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re - C2.Re;
aux.Im = this.Im - C2.Im;
return aux;
}
public double Magnitude()
{
double Len = Math.Sqrt(this.Re * this.Re + this.Im * this.Im);
double bb = Math.Abs(Math.Tan(this.Re / Len)) / Math.Tan(this.Re / Len);
return (Len * bb );
}
public Complex Rev()
{
Complex aux = new Complex();
aux.Re = this.Re;
aux.Im = -1.0d * this.Im;
return aux;
}
}
public List<complex> Cos_Fun(int N)
{
List<complex> cc = new List<complex>(N);
Complex aux;
double c = 2.0d * DDC_PI / (double)N;
for (int i = 0; i < N; i++)
{
aux = new Complex(
Math.Cos((double)(3 * i) * c)
, Math.Sin((double)(6 * i * i) * c)
);
cc.Add(aux);
}
return cc;
}

public const Double DDC_PI = 3.14159265358979323846;
UInt32 Block_Size = 2;

public Complex Get_W(int block_size, int index)
{
Complex c = new Complex(1.0d, 1.0d);
c.Re = c.Re * Math.Cos((-2 * DDC_PI / block_size) * index);
c.Im = c.Im * Math.Sin((-2 * DDC_PI / block_size) * index);
return c;
}
public List<complex> Init_FFT(List<complex> x)
{
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(x.Count);
UInt32 count;
if (IsPowerOfTwo((UInt32)x.Count))
{
count = (UInt32)x.Count;
}
else
{
count = NextPowerOfTwo((UInt32)x.Count);
}
UInt32 b = NumberOfBitsNeeded(count);
aux = new List<complex>((int)count);
Complex cccc= new Complex();
for (int i = 0; i < (int)count; i++)
{
aux.Add(cccc);
}
for (int i = x.Count; i < count; i++)
{
x.Add(auxx);
}
for (int i = 0; i < count; i++)
{
aux[i] = (x[(int)ReverseBits((UInt32)i, b)]);
}
x.Clear();
return aux;
}
public List<complex> FFT_Calc(List<complex> Xx)
{
Block_Size = 2; int index = 0; int indexx = 0;
int Block_num = Xx.Count / (int)Block_Size;
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(Xx.Count);
for (int i = 0; i < Xx.Count; i++)
aux.Add(auxx);
int test = 0;
while (Block_Size <= Xx.Count)
{
index = 0;
Block_num = Xx.Count / (int)Block_Size;
for (int i = 0; i < Block_num; i++)
{
indexx = 0; index = i * (int)Block_Size;
for (int j = 0; j < (int)Block_Size / 2; j++)
{
//first
auxx = Get_W((int)Block_Size, indexx);
aux[index] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index] = aux[index].Add(auxx);
test++;
//second
auxx = Get_W((int)Block_Size, indexx + (int)Block_Size / 2);
aux[index + (int)Block_Size / 2] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
test++;
indexx++;
index++;
}
}
for (int k = 0; k < aux.Count; k++)
Xx[k] = aux[k];
Block_Size <<= 1;
}
//for (int k = 0; k < aux.Count; k++)
// Xx[k] = aux[k];
return aux;
}
public List<complex> Inv_FFT_Calc(List<complex> Xx)
{
Block_Size = 2; int index = 0; int indexx = 0;
int Block_num = Xx.Count / (int)Block_Size;
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(Xx.Count);
for (int i = 0; i < Xx.Count; i++)
aux.Add(auxx);
int test = 0;
while (Block_Size <= Xx.Count)
{
index = 0;
Block_num = Xx.Count / (int)Block_Size;
for (int i = 0; i < Block_num; i++)
{
indexx = 0; index = i * (int)Block_Size;
for (int j = 0; j < (int)Block_Size / 2; j++)
{
//first
auxx = Get_W((int)Block_Size, -indexx);
aux[index] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index] = aux[index].Add(auxx);
test++;
//second
auxx = Get_W((int)Block_Size, -indexx + (int)Block_Size / 2);
aux[index + (int)Block_Size / 2] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
test++;
indexx++;
index++;
}
}
for (int k = 0; k < aux.Count; k++)
Xx[k] = aux[k];
Block_Size <<= 1;
}
Complex c = new Complex(1.0d / aux.Count, 0.0d);
List<complex> auxxx = new List<complex>(aux.Count);
for (int k = 0; k < aux.Count; k++)
{
c.Re = aux[k].Re / (double)aux.Count; c.Im = 0.0d;
auxxx.Add(c);
}
//UInt32 b = NumberOfBitsNeeded((uint)aux.Count);
//for (int k = 0; k < aux.Count; k++)
//{
// Xx[k] = aux[k];
// //Xx[(int)ReverseBits((UInt32)k, b)] = aux[k];
//}

return auxxx;
}

public System.Drawing.Bitmap Draw_Spectral(float[] Percent, int From, int To, Color c, System.Drawing.Size Bitmap_Size)
{
Bitmap bb = new Bitmap(Bitmap_Size.Width, Bitmap_Size.Height);
if (Percent != null)
{
System.Drawing.Graphics g = Graphics.FromImage(bb);
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.Clear(Color.White);
float max = 0.0f;
for (int i = From; i < To; i++)
{
if (max < Percent[i])
max = Percent[i];
}
float xStep = ((float)bb.Width - 10.0f) / (float)(To - From);
System.Drawing.SolidBrush sb1 = new SolidBrush(Color.LightBlue);
System.Drawing.Pen p1 = new Pen(c, 1.5f);
float yStep = 1.0f * ((float)bb.Height - 10.0f) / max;
float x = 5.0f, y = bb.Height - 5.0f;
for (int i = From; i < To; i++)
{
g.DrawLine(p1
, x
, bb.Height - 5.0f
, x
, y - (Percent[i] * yStep));
x += xStep;
}
}
return bb;
}

public void Draw_Wave(List<complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f;
for (int i = 0; i < Spectral.Count; i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
}
float xStep = ((float)p.Width - 10.0f) / Spectral.Count;
System.Drawing.Pen p1 = new Pen(c, D_Width);
float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
float x = 5.0f, y = p.Height - 5.0f;
for (int i = 0; i < Spectral.Count; i++)
{
g.DrawLine(p1
, x
, p.Height - 5.0f
, x
, y - ((float)Spectral[i].Magnitude() * yStep));
x += xStep;
}
}
}
public enum Complex_Part
{
Real,
Image,
Magenda
}
public void Draw_Spectral(List<complex> Spectral, System.Windows.Forms.Panel p,Complex_Part cp, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f; float min = 0.0f; ;
int freq_step = (Spectral.Count) * 10 / 100;
int f_s = freq_step;
if (cp == Complex_Part.Image)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Im)
max = (float)Spectral[i].Im;
if (min > Spectral[i].Im)
min = (float)Spectral[i].Im;
}
}
else if (cp == Complex_Part.Real)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Re)
max = (float)Spectral[i].Re;
if (min > Spectral[i].Re)
min = (float)Spectral[i].Re;
}
}
else if (cp == Complex_Part.Magenda)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
if (min > Spectral[i].Magnitude())
min = (float)Spectral[i].Magnitude();
}
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Count);
System.Drawing.Pen p1 = new Pen(c, D_Width);
System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
float x = 5.0f, y = p.Height - (10.0f - yStep * min);
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);

for (int i = 0; i < (Spectral.Count); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p2
, x - xStep
, p.Height - (10.0f - yStep * min)
, x + xStep
, p.Height - (10.0f - yStep * min));

if (cp == Complex_Part.Image)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Im) * yStep));
}
else if (cp == Complex_Part.Real)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Re) * yStep));
}
else if (cp == Complex_Part.Magenda)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Magnitude()) * yStep));
}


x += xStep;
}
}
}
public void Draw_Spectral(List<complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f; float min = 0.0f; ;
int freq_step = (Spectral.Count / 2) * 10 / 100;
int f_s = freq_step;
for (int i = 0; i < (Spectral.Count/2); i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
if (min > Spectral[i].Magnitude())
min = (float)Spectral[i].Magnitude();
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Count / 2);
System.Drawing.Pen p1 = new Pen(c, D_Width);
System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
float x = 5.0f, y = p.Height - (10.0f - yStep * min);
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);
for (int i = 0; i < (Spectral.Count / 2); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Magnitude()) * yStep ));
g.DrawLine(p2
, x - xStep
, p.Height - (10.0f - yStep * min)
, x + xStep
, p.Height - (10.0f - yStep * min));
x += xStep;
}
}
}
public void Draw_Spectral(double[] Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f;
int freq_step = (Spectral.Length) * 5 / 100;
int f_s = freq_step;
for (int i = 0; i < Spectral.Length; i++)
{
if (max < Math.Abs(Spectral[i]))
max = (float)Math.Abs(Spectral[i]);
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Length);
System.Drawing.Pen p1 = new Pen(c, D_Width);
float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
float x = 5.0f, y = p.Height - 5.0f;
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);
for (int i = 0; i < (Spectral.Length); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p1
, x
, p.Height - 5.0f
, x
, y - ((float)Math.Abs(Spectral[i]) * yStep));
x += xStep;
}
}
}
public List<complex> InitRSine(int n)
{
List<complex> Data_In = new List<complex>();
Complex aux = new Complex();
for (int i = 0; i < n; i++)
{
aux = new Complex();
aux.Re =
Math.Cos((double)(45.0) * i * (0.5 * Math.PI / n))
+ 4.0d * Math.Cos((double)(60.0) * i * (0.1 * Math.PI / n))
//+ Math.Cos((double)(20.0) * i * (2.0 * Math.PI / n))
//+ Math.Cos((double)(10.0) * i * (2.0 * Math.PI / n))
//+ Math.Cos((double)(5.0) * i * (2.0 * Math.PI / n))
;
aux.Im = 0.0d;
Data_In.Add(aux);
}
return Data_In;
}


}
 
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Posted
Comments
Member 13750418 13-May-18 8:00am    
im getting error on complex variable how to resolve that problem
Quote:

public class FFT
{
public static Boolean IsPowerOfTwo(UInt32 x)
{
return ((x != 0) && (x & (x - 1)) == 0);
}
public static UInt32 NextPowerOfTwo(UInt32 x)
{
x = x - 1;
x = x | (x >> 1);
x = x | (x >> 2);
x = x | (x >> 4);
x = x | (x >> 8);
x = x | (x >> 16);
return x + 1;
}
public static UInt32 NumberOfBitsNeeded(UInt32 PowerOfTwo)
{
if (PowerOfTwo > 0)
{
for (UInt32 i = 0, mask = 1; ; i++, mask <<= 1)
{
if ((PowerOfTwo & mask) != 0)
return i;
}
}
return 0; // error
}
public static UInt32 ReverseBits(UInt32 index, UInt32 NumBits)
{
UInt32 i, rev;

for (i = rev = 0; i < NumBits; i++)
{
rev = (rev << 1) | (index & 1);
index >>= 1;
}

return rev;
}
public struct Complex
{
public double Re, Im;
public Complex(double x, double y)
{
this.Re = x; this.Im = y;
}
public Complex Mul(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re * C2.Re - this.Im * C2.Im;
aux.Im = this.Re * C2.Im + this.Im * C2.Re;
return aux;
}
public Complex Add(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re + C2.Re;
aux.Im = this.Im + C2.Im;
return aux;
}
public Complex Sub(Complex C2)
{
Complex aux = new Complex();
aux.Re = this.Re - C2.Re;
aux.Im = this.Im - C2.Im;
return aux;
}
public double Magnitude()
{
double Len = Math.Sqrt(this.Re * this.Re + this.Im * this.Im);
double bb = Math.Abs(Math.Tan(this.Re / Len)) / Math.Tan(this.Re / Len);
return (Len * bb );
}
public Complex Rev()
{
Complex aux = new Complex();
aux.Re = this.Re;
aux.Im = -1.0d * this.Im;
return aux;
}
}
public List<complex> Cos_Fun(int N)
{
List<complex> cc = new List<complex>(N);
Complex aux;
double c = 2.0d * DDC_PI / (double)N;
for (int i = 0; i < N; i++)
{
aux = new Complex(
Math.Cos((double)(3 * i) * c)
, Math.Sin((double)(6 * i * i) * c)
);
cc.Add(aux);
}
return cc;
}

public const Double DDC_PI = 3.14159265358979323846;
UInt32 Block_Size = 2;

public Complex Get_W(int block_size, int index)
{
Complex c = new Complex(1.0d, 1.0d);
c.Re = c.Re * Math.Cos((-2 * DDC_PI / block_size) * index);
c.Im = c.Im * Math.Sin((-2 * DDC_PI / block_size) * index);
return c;
}
public List<complex> Init_FFT(List<complex> x)
{
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(x.Count);
UInt32 count;
if (IsPowerOfTwo((UInt32)x.Count))
{
count = (UInt32)x.Count;
}
else
{
count = NextPowerOfTwo((UInt32)x.Count);
}
UInt32 b = NumberOfBitsNeeded(count);
aux = new List<complex>((int)count);
Complex cccc= new Complex();
for (int i = 0; i < (int)count; i++)
{
aux.Add(cccc);
}
for (int i = x.Count; i < count; i++)
{
x.Add(auxx);
}
for (int i = 0; i < count; i++)
{
aux[i] = (x[(int)ReverseBits((UInt32)i, b)]);
}
x.Clear();
return aux;
}
public List<complex> FFT_Calc(List<complex> Xx)
{
Block_Size = 2; int index = 0; int indexx = 0;
int Block_num = Xx.Count / (int)Block_Size;
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(Xx.Count);
for (int i = 0; i < Xx.Count; i++)
aux.Add(auxx);
int test = 0;
while (Block_Size <= Xx.Count)
{
index = 0;
Block_num = Xx.Count / (int)Block_Size;
for (int i = 0; i < Block_num; i++)
{
indexx = 0; index = i * (int)Block_Size;
for (int j = 0; j < (int)Block_Size / 2; j++)
{
//first
auxx = Get_W((int)Block_Size, indexx);
aux[index] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index] = aux[index].Add(auxx);
test++;
//second
auxx = Get_W((int)Block_Size, indexx + (int)Block_Size / 2);
aux[index + (int)Block_Size / 2] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
test++;
indexx++;
index++;
}
}
for (int k = 0; k < aux.Count; k++)
Xx[k] = aux[k];
Block_Size <<= 1;
}
//for (int k = 0; k < aux.Count; k++)
// Xx[k] = aux[k];
return aux;
}
public List<complex> Inv_FFT_Calc(List<complex> Xx)
{
Block_Size = 2; int index = 0; int indexx = 0;
int Block_num = Xx.Count / (int)Block_Size;
Complex auxx = new Complex(0.0d, 0.0d);
List<complex> aux = new List<complex>(Xx.Count);
for (int i = 0; i < Xx.Count; i++)
aux.Add(auxx);
int test = 0;
while (Block_Size <= Xx.Count)
{
index = 0;
Block_num = Xx.Count / (int)Block_Size;
for (int i = 0; i < Block_num; i++)
{
indexx = 0; index = i * (int)Block_Size;
for (int j = 0; j < (int)Block_Size / 2; j++)
{
//first
auxx = Get_W((int)Block_Size, -indexx);
aux[index] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index] = aux[index].Add(auxx);
test++;
//second
auxx = Get_W((int)Block_Size, -indexx + (int)Block_Size / 2);
aux[index + (int)Block_Size / 2] = Xx[index];
auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
test++;
indexx++;
index++;
}
}
for (int k = 0; k < aux.Count; k++)
Xx[k] = aux[k];
Block_Size <<= 1;
}
Complex c = new Complex(1.0d / aux.Count, 0.0d);
List<complex> auxxx = new List<complex>(aux.Count);
for (int k = 0; k < aux.Count; k++)
{
c.Re = aux[k].Re / (double)aux.Count; c.Im = 0.0d;
auxxx.Add(c);
}
//UInt32 b = NumberOfBitsNeeded((uint)aux.Count);
//for (int k = 0; k < aux.Count; k++)
//{
// Xx[k] = aux[k];
// //Xx[(int)ReverseBits((UInt32)k, b)] = aux[k];
//}

return auxxx;
}

public System.Drawing.Bitmap Draw_Spectral(float[] Percent, int From, int To, Color c, System.Drawing.Size Bitmap_Size)
{
Bitmap bb = new Bitmap(Bitmap_Size.Width, Bitmap_Size.Height);
if (Percent != null)
{
System.Drawing.Graphics g = Graphics.FromImage(bb);
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.Clear(Color.White);
float max = 0.0f;
for (int i = From; i < To; i++)
{
if (max < Percent[i])
max = Percent[i];
}
float xStep = ((float)bb.Width - 10.0f) / (float)(To - From);
System.Drawing.SolidBrush sb1 = new SolidBrush(Color.LightBlue);
System.Drawing.Pen p1 = new Pen(c, 1.5f);
float yStep = 1.0f * ((float)bb.Height - 10.0f) / max;
float x = 5.0f, y = bb.Height - 5.0f;
for (int i = From; i < To; i++)
{
g.DrawLine(p1
, x
, bb.Height - 5.0f
, x
, y - (Percent[i] * yStep));
x += xStep;
}
}
return bb;
}

public void Draw_Wave(List<complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f;
for (int i = 0; i < Spectral.Count; i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
}
float xStep = ((float)p.Width - 10.0f) / Spectral.Count;
System.Drawing.Pen p1 = new Pen(c, D_Width);
float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
float x = 5.0f, y = p.Height - 5.0f;
for (int i = 0; i < Spectral.Count; i++)
{
g.DrawLine(p1
, x
, p.Height - 5.0f
, x
, y - ((float)Spectral[i].Magnitude() * yStep));
x += xStep;
}
}
}
public enum Complex_Part
{
Real,
Image,
Magenda
}
public void Draw_Spectral(List<complex> Spectral, System.Windows.Forms.Panel p,Complex_Part cp, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f; float min = 0.0f; ;
int freq_step = (Spectral.Count) * 10 / 100;
int f_s = freq_step;
if (cp == Complex_Part.Image)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Im)
max = (float)Spectral[i].Im;
if (min > Spectral[i].Im)
min = (float)Spectral[i].Im;
}
}
else if (cp == Complex_Part.Real)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Re)
max = (float)Spectral[i].Re;
if (min > Spectral[i].Re)
min = (float)Spectral[i].Re;
}
}
else if (cp == Complex_Part.Magenda)
{
for (int i = 0; i < (Spectral.Count); i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
if (min > Spectral[i].Magnitude())
min = (float)Spectral[i].Magnitude();
}
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Count);
System.Drawing.Pen p1 = new Pen(c, D_Width);
System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
float x = 5.0f, y = p.Height - (10.0f - yStep * min);
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);

for (int i = 0; i < (Spectral.Count); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p2
, x - xStep
, p.Height - (10.0f - yStep * min)
, x + xStep
, p.Height - (10.0f - yStep * min));

if (cp == Complex_Part.Image)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Im) * yStep));
}
else if (cp == Complex_Part.Real)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Re) * yStep));
}
else if (cp == Complex_Part.Magenda)
{
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Magnitude()) * yStep));
}


x += xStep;
}
}
}
public void Draw_Spectral(List<complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f; float min = 0.0f; ;
int freq_step = (Spectral.Count / 2) * 10 / 100;
int f_s = freq_step;
for (int i = 0; i < (Spectral.Count/2); i++)
{
if (max < Spectral[i].Magnitude())
max = (float)Spectral[i].Magnitude();
if (min > Spectral[i].Magnitude())
min = (float)Spectral[i].Magnitude();
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Count / 2);
System.Drawing.Pen p1 = new Pen(c, D_Width);
System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
float x = 5.0f, y = p.Height - (10.0f - yStep * min);
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);
for (int i = 0; i < (Spectral.Count / 2); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p1
, x
, p.Height - (10.0f - yStep * min)
, x
, y - (((float)Spectral[i].Magnitude()) * yStep ));
g.DrawLine(p2
, x - xStep
, p.Height - (10.0f - yStep * min)
, x + xStep
, p.Height - (10.0f - yStep * min));
x += xStep;
}
}
}
public void Draw_Spectral(double[] Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
{
if (Spectral != null)
{
System.Drawing.Graphics g = p.CreateGraphics();
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
g.Clear(Color.White);
float max = 0.0f;
int freq_step = (Spectral.Length) * 5 / 100;
int f_s = freq_step;
for (int i = 0; i < Spectral.Length; i++)
{
if (max < Math.Abs(Spectral[i]))
max = (float)Math.Abs(Spectral[i]);
}
float xStep = ((float)p.Width - 10.0f) / (Spectral.Length);
System.Drawing.Pen p1 = new Pen(c, D_Width);
float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
float x = 5.0f, y = p.Height - 5.0f;
Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
SolidBrush b = new SolidBrush(Color.Black);
for (int i = 0; i < (Spectral.Length); i++)
{
if (i == f_s)
{
g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
f_s += freq_step;
}
g.DrawLine(p1
, x
, p.Height - 5.0f
, x
, y - ((float)Math.Abs(Spectral[i]) * yStep));
x += xStep;
}
}
}
public List<complex> InitRSine(int n)
{
List<complex> Data_In = new List<complex>();
Complex aux = new Complex();
for (int i = 0; i < n; i++)
{
aux = new Complex();
aux.Re =
Math.Cos((double)(45.0) * i * (0.5 * Math.PI / n))
+ 4.0d * Math.Cos((double)(60.0) * i * (0.1 * Math.PI / n))
//+ Math.Cos((double)(20.0) * i * (2.0 * Math.PI / n))
//+ Math.Cos((double)(10.0) * i * (2.0 * Math.PI / n))
//+ Math.Cos((double)(5.0) * i * (2.0 * Math.PI / n))
;
aux.Im = 0.0d;
Data_In.Add(aux);
}
return Data_In;
}


}
 
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Posted 
public class FFT
    {
        public static Boolean IsPowerOfTwo(UInt32 x)
        {
            return ((x != 0) && (x & (x - 1)) == 0);
        }
        public static UInt32 NextPowerOfTwo(UInt32 x)
        {
            x = x - 1;
            x = x | (x >> 1);
            x = x | (x >> 2);
            x = x | (x >> 4);
            x = x | (x >> 8);
            x = x | (x >> 16);
            return x + 1;
        }
        public static UInt32 NumberOfBitsNeeded(UInt32 PowerOfTwo)
        {
            if (PowerOfTwo > 0)
            {
                for (UInt32 i = 0, mask = 1; ; i++, mask <<= 1)
                {
                    if ((PowerOfTwo & mask) != 0)
                        return i;
                }
            }
            return 0; // error
        }
        public static UInt32 ReverseBits(UInt32 index, UInt32 NumBits)
        {
            UInt32 i, rev;

            for (i = rev = 0; i < NumBits; i++)
            {
                rev = (rev << 1) | (index & 1);
                index >>= 1;
            }

            return rev;
        }
        public struct Complex
        {
            public double Re, Im;
            public Complex(double x, double y)
            {
                this.Re = x; this.Im = y;
            }
            public Complex Mul(Complex C2)
            {
                Complex aux = new Complex();
                aux.Re = this.Re * C2.Re - this.Im * C2.Im;
                aux.Im = this.Re * C2.Im + this.Im * C2.Re;
                return aux;
            }
            public Complex Add(Complex C2)
            {
                Complex aux = new Complex();
                aux.Re = this.Re + C2.Re;
                aux.Im = this.Im + C2.Im;
                return aux;
            }
            public Complex Sub(Complex C2)
            {
                Complex aux = new Complex();
                aux.Re = this.Re - C2.Re;
                aux.Im = this.Im - C2.Im;
                return aux;
            }
            public double Magnitude()
            {
                double Len = Math.Sqrt(this.Re * this.Re + this.Im * this.Im);
                double bb = Math.Abs(Math.Tan(this.Re / Len)) / Math.Tan(this.Re / Len);
                return (Len * bb );
            }
            public Complex Rev()
            {
                Complex aux = new Complex();
                aux.Re = this.Re;
                aux.Im = -1.0d * this.Im;
                return aux;
            }
        }
        public List<Complex> Cos_Fun(int N)
        {
            List<Complex> cc = new List<Complex>(N);
            Complex aux;
            double c = 2.0d * DDC_PI / (double)N;
            for (int i = 0; i < N; i++)
            {
                aux = new Complex(
                      Math.Cos((double)(3 * i) * c)
                    , Math.Sin((double)(6 * i * i) * c)
                    );
                cc.Add(aux);
            }
            return cc;
        }

        public const Double DDC_PI = 3.14159265358979323846;
        UInt32 Block_Size = 2;

        public Complex Get_W(int block_size, int index)
        {
            Complex c = new Complex(1.0d, 1.0d);
            c.Re = c.Re * Math.Cos((-2 * DDC_PI / block_size) * index);
            c.Im = c.Im * Math.Sin((-2 * DDC_PI / block_size) * index);
            return c;
        }
        public List<Complex> Init_FFT(List<Complex> x)
        {
            Complex auxx = new Complex(0.0d, 0.0d);
            List<Complex> aux = new List<Complex>(x.Count);
            UInt32 count;
            if (IsPowerOfTwo((UInt32)x.Count))
            {
                count = (UInt32)x.Count;
            }
            else
            {
                count = NextPowerOfTwo((UInt32)x.Count);
            }
            UInt32 b = NumberOfBitsNeeded(count);
            aux = new List<Complex>((int)count);
            Complex cccc= new Complex();
            for (int i = 0; i < (int)count; i++)
            {
                aux.Add(cccc);
            }            
            for (int i = x.Count; i < count; i++)
            {
                x.Add(auxx);
            }
            for (int i = 0; i < count; i++)
            {
                aux[i] = (x[(int)ReverseBits((UInt32)i, b)]);
            }
            x.Clear();
            return aux;
        }
       public List<Complex> FFT_Calc(List<Complex> Xx)
        {
            Block_Size = 2; int index = 0; int indexx = 0;
            int Block_num = Xx.Count / (int)Block_Size;
            Complex auxx = new Complex(0.0d, 0.0d);
            List<Complex> aux = new List<Complex>(Xx.Count);
            for (int i = 0; i < Xx.Count; i++)
                aux.Add(auxx);
            int test = 0;
            while (Block_Size <= Xx.Count)
            {
                index = 0;
                Block_num = Xx.Count / (int)Block_Size;
                for (int i = 0; i < Block_num; i++)
                {
                    indexx = 0; index = i * (int)Block_Size;
                    for (int j = 0; j < (int)Block_Size / 2; j++)
                    {
                        //first
                        auxx = Get_W((int)Block_Size, indexx);
                        aux[index] = Xx[index];
                        auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
                        aux[index] = aux[index].Add(auxx);
                        test++;
                        //second
                        auxx = Get_W((int)Block_Size, indexx + (int)Block_Size / 2);
                        aux[index + (int)Block_Size / 2] = Xx[index];
                        auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
                        aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
                        test++;
                        indexx++;
                        index++;
                    }
                }
                for (int k = 0; k < aux.Count; k++)
                    Xx[k] = aux[k];
                Block_Size <<= 1;
            }
            //for (int k = 0; k < aux.Count; k++)
            //    Xx[k] = aux[k];
            return aux;
        }
       public List<Complex> Inv_FFT_Calc(List<Complex> Xx)
       {
           Block_Size = 2; int index = 0; int indexx = 0;
           int Block_num = Xx.Count / (int)Block_Size;
           Complex auxx = new Complex(0.0d, 0.0d);
           List<Complex> aux = new List<Complex>(Xx.Count);
           for (int i = 0; i < Xx.Count; i++)
               aux.Add(auxx);
           int test = 0;
           while (Block_Size <= Xx.Count)
           {
               index = 0;
               Block_num = Xx.Count / (int)Block_Size;
               for (int i = 0; i < Block_num; i++)
               {
                   indexx = 0; index = i * (int)Block_Size;
                   for (int j = 0; j < (int)Block_Size / 2; j++)
                   {
                       //first
                       auxx = Get_W((int)Block_Size, -indexx);
                       aux[index] = Xx[index];
                       auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
                       aux[index] = aux[index].Add(auxx);
                       test++;
                       //second
                       auxx = Get_W((int)Block_Size, -indexx + (int)Block_Size / 2);
                       aux[index + (int)Block_Size / 2] = Xx[index];
                       auxx = auxx.Mul(Xx[index + (int)Block_Size / 2]);
                       aux[index + (int)Block_Size / 2] = aux[index + (int)Block_Size / 2].Add(auxx);
                       test++;
                       indexx++;
                       index++;
                   }
               }
               for (int k = 0; k < aux.Count; k++)
                   Xx[k] = aux[k];
               Block_Size <<= 1;
           }
           Complex c = new Complex(1.0d / aux.Count, 0.0d);
           List<Complex> auxxx = new List<Complex>(aux.Count);
           for (int k = 0; k < aux.Count; k++)
           {
               c.Re = aux[k].Re / (double)aux.Count; c.Im = 0.0d;
               auxxx.Add(c);
           }
           //UInt32 b = NumberOfBitsNeeded((uint)aux.Count);
           //for (int k = 0; k < aux.Count; k++)
           //{
           //    Xx[k] = aux[k];
           //    //Xx[(int)ReverseBits((UInt32)k, b)] = aux[k];
           //}
               
           return auxxx;
       }  

        public System.Drawing.Bitmap Draw_Spectral(float[] Percent, int From, int To, Color c, System.Drawing.Size Bitmap_Size)
        {
            Bitmap bb = new Bitmap(Bitmap_Size.Width, Bitmap_Size.Height);
            if (Percent != null)
            {
                System.Drawing.Graphics g = Graphics.FromImage(bb);
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                g.Clear(Color.White);
                float max = 0.0f;
                for (int i = From; i < To; i++)
                {
                    if (max < Percent[i])
                        max = Percent[i];
                }
                float xStep = ((float)bb.Width - 10.0f) / (float)(To - From);
                System.Drawing.SolidBrush sb1 = new SolidBrush(Color.LightBlue);
                System.Drawing.Pen p1 = new Pen(c, 1.5f);
                float yStep = 1.0f * ((float)bb.Height - 10.0f) / max;
                float x = 5.0f, y = bb.Height - 5.0f;
                for (int i = From; i < To; i++)
                {
                    g.DrawLine(p1
                        , x
                        , bb.Height - 5.0f
                        , x
                        , y - (Percent[i] * yStep));
                    x += xStep;
                }
            }
            return bb;
        }
        
        public void Draw_Wave(List<Complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
        {
            if (Spectral != null)
            {
                System.Drawing.Graphics g = p.CreateGraphics();
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
                g.Clear(Color.White);
                float max = 0.0f;
                for (int i = 0; i < Spectral.Count; i++)
                {
                    if (max < Spectral[i].Magnitude())
                        max = (float)Spectral[i].Magnitude();
                }
                float xStep = ((float)p.Width - 10.0f) / Spectral.Count;
                System.Drawing.Pen p1 = new Pen(c, D_Width);
                float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
                float x = 5.0f, y = p.Height - 5.0f;
                for (int i = 0; i < Spectral.Count; i++)
                {
                    g.DrawLine(p1
                        , x
                        , p.Height - 5.0f
                        , x
                        , y - ((float)Spectral[i].Magnitude() * yStep));
                    x += xStep;
                }
            }
        }
        public enum Complex_Part
        {
            Real,
            Image,
            Magenda
        }
        public void Draw_Spectral(List<Complex> Spectral, System.Windows.Forms.Panel p,Complex_Part cp, Color c, float D_Width)
        {
            if (Spectral != null)
            {
                System.Drawing.Graphics g = p.CreateGraphics();
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
                g.Clear(Color.White);
                float max = 0.0f; float min = 0.0f; ;
                int freq_step = (Spectral.Count) * 10 / 100;
                int f_s = freq_step;
                if (cp == Complex_Part.Image)
                {
                    for (int i = 0; i < (Spectral.Count); i++)
                    {
                        if (max < Spectral[i].Im)
                            max = (float)Spectral[i].Im;
                        if (min > Spectral[i].Im)
                            min = (float)Spectral[i].Im;
                    }
                }
                else if (cp == Complex_Part.Real)
                {
                    for (int i = 0; i < (Spectral.Count); i++)
                    {
                        if (max < Spectral[i].Re)
                            max = (float)Spectral[i].Re;
                        if (min > Spectral[i].Re)
                            min = (float)Spectral[i].Re;
                    }
                }
                else if (cp == Complex_Part.Magenda)
                {
                    for (int i = 0; i < (Spectral.Count); i++)
                    {
                        if (max < Spectral[i].Magnitude())
                            max = (float)Spectral[i].Magnitude();
                        if (min > Spectral[i].Magnitude())
                            min = (float)Spectral[i].Magnitude();
                    }
                }
                float xStep = ((float)p.Width - 10.0f) / (Spectral.Count);
                System.Drawing.Pen p1 = new Pen(c, D_Width);
                System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
                float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
                float x = 5.0f, y = p.Height - (10.0f - yStep * min);
                Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
                SolidBrush b = new SolidBrush(Color.Black);

                for (int i = 0; i < (Spectral.Count); i++)
                {
                    if (i == f_s)
                    {
                        g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
                        f_s += freq_step;
                    }
                    g.DrawLine(p2
                       , x - xStep
                       , p.Height - (10.0f - yStep * min)
                       , x + xStep
                       , p.Height - (10.0f - yStep * min));

                    if (cp == Complex_Part.Image)
                    {
                        g.DrawLine(p1
                        , x
                        , p.Height - (10.0f - yStep * min)
                        , x
                        , y - (((float)Spectral[i].Im) * yStep));
                    }
                    else if (cp == Complex_Part.Real)
                    {
                        g.DrawLine(p1
                        , x
                        , p.Height - (10.0f - yStep * min)
                        , x
                        , y - (((float)Spectral[i].Re) * yStep));
                    }
                    else if (cp == Complex_Part.Magenda)
                    {
                        g.DrawLine(p1
                        , x
                        , p.Height - (10.0f - yStep * min)
                        , x
                        , y - (((float)Spectral[i].Magnitude()) * yStep)); 
                    }
                   
                   
                    x += xStep;
                }
            }
        }
        public void Draw_Spectral(List<Complex> Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
        {
            if (Spectral != null)
            {
                System.Drawing.Graphics g = p.CreateGraphics();
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
                g.Clear(Color.White);
                float max = 0.0f; float min = 0.0f; ;
                int freq_step = (Spectral.Count / 2) * 10 / 100;
                int f_s = freq_step;
                for (int i = 0; i < (Spectral.Count/2); i++)
                {
                    if (max < Spectral[i].Magnitude())
                        max = (float)Spectral[i].Magnitude();
                    if (min > Spectral[i].Magnitude())
                        min = (float)Spectral[i].Magnitude();
                }
                float xStep = ((float)p.Width - 10.0f) / (Spectral.Count / 2);
                System.Drawing.Pen p1 = new Pen(c, D_Width);
                System.Drawing.Pen p2 = new Pen(Color.Black, 1.0f);
                float yStep = 1.0f * ((float)p.Height - 20.0f) / (max - min);
                float x = 5.0f, y = p.Height - (10.0f - yStep * min);
                Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
                SolidBrush b = new SolidBrush(Color.Black);
                for (int i = 0; i < (Spectral.Count / 2); i++)
                {
                    if (i == f_s)
                    {
                        g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
                        f_s += freq_step;
                    }
                    g.DrawLine(p1
                        , x
                        , p.Height - (10.0f  - yStep * min)
                        , x
                        , y - (((float)Spectral[i].Magnitude()) * yStep ));
                    g.DrawLine(p2
                        , x - xStep
                        , p.Height - (10.0f - yStep * min)
                        , x + xStep
                        , p.Height - (10.0f - yStep * min));
                    x += xStep;
                }
            }
        }
        public void Draw_Spectral(double[] Spectral, System.Windows.Forms.Panel p, Color c, float D_Width)
        {
            if (Spectral != null)
            {
                System.Drawing.Graphics g = p.CreateGraphics();
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
                g.Clear(Color.White);
                float max = 0.0f;
                int freq_step = (Spectral.Length) * 5 / 100;
                int f_s = freq_step;
                for (int i = 0; i < Spectral.Length; i++)
                {
                    if (max < Math.Abs(Spectral[i]))
                        max = (float)Math.Abs(Spectral[i]);
                }
                float xStep = ((float)p.Width - 10.0f) / (Spectral.Length);
                System.Drawing.Pen p1 = new Pen(c, D_Width);
                float yStep = 1.0f * ((float)p.Height - 10.0f) / max;
                float x = 5.0f, y = p.Height - 5.0f;
                Font f = new Font("Tahoma", 6.5f, FontStyle.Regular);
                SolidBrush b = new SolidBrush(Color.Black);
                for (int i = 0; i < (Spectral.Length); i++)
                {
                    if (i == f_s)
                    {
                        g.DrawString(f_s + "", f, b, x - 25.0f, 5.0f);
                        f_s += freq_step;
                    }
                    g.DrawLine(p1
                        , x
                        , p.Height - 5.0f
                        , x
                        , y - ((float)Math.Abs(Spectral[i]) * yStep));
                    x += xStep;
                }
            }
        }
        public List<Complex> InitRSine(int n)
        {
            List<Complex> Data_In = new List<Complex>();
            Complex aux = new Complex();
            for (int i = 0; i < n; i++)
            {
                aux = new Complex();
                aux.Re =
                    Math.Cos((double)(45.0) * i * (0.5 * Math.PI / n))
                    + 4.0d * Math.Cos((double)(60.0) * i * (0.1 * Math.PI / n))
                    //+ Math.Cos((double)(20.0) * i * (2.0 * Math.PI / n)) 
                    //+ Math.Cos((double)(10.0) * i * (2.0 * Math.PI / n))
                    //+ Math.Cos((double)(5.0) * i * (2.0 * Math.PI / n))
                    ;
                aux.Im = 0.0d;
                Data_In.Add(aux);
            }
            return Data_In;
        }


    }
 
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Posted
" i cannot find any implementation of FFT in C#"

You didn't look too hard, then - did you?
A very, very quick Google for "Fast Fourier Transform C#" gave 85,000 hits: Google[^]

That you don't understand them is your problem, not ours: and not something we can resolve. You may not need to understand them - just use them.
 
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