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Real-Time FFT Analysis

The Real-Time FFT Analysis can be downloaded at //www.hotshare.net/file/151022-86519127f9.html

snap short:

source code:

void SantiFFT::DoFFT(double *rData, double *iData, unsigned InvertFlag, unsigned FFTSize, unsigned ReplaceFlag)
{
   register unsigned i, j;
   unsigned n, k, idx, BlockEnd, BlockSize;
   double tr, ti; // Temporal vriables;

   Resize(FFTSize); // Update 'Size' , 'NumBits' and Parameters

   for(i=0; i   { j = ReverseBits(i, NumBits);
   Real.Data[j] = rData[i];
   Imag.Data[j] = (iData[i] == NULL) ? 0.0 : iData[i];
   }

   BlockEnd = 1;

   idx = (InvertFlag)?NumBits:0;
   for (idx=idx, BlockSize=2; BlockSize<=FFTSize; BlockSize<<=1, idx++)
   { double sm2,sm1,cm2,cm1,w,ar[3],ai[3],temp;
   sm2 = xsm2.Data[idx];
   sm1 = xsm1.Data[idx];
   cm2 = xcm2.Data[idx];
   cm1 = xcm1.Data[idx];
   w = xw.Data[idx];

   for ( i=0; i < FFTSize; i += BlockSize )
   {
   ar[2] = cm2;
   ar[1] = cm1;

   ai[2] = sm2;
   ai[1] = sm1;

   for ( j=i, n=0; n < BlockEnd; j++, n++ )
   {
   ar[0] = w*ar[1] - ar[2];
   ar[2] = ar[1];
   ar[1] = ar[0];

   ai[0] = w*ai[1] - ai[2];
   ai[2] = ai[1];
   ai[1] = ai[0];

   k = j + BlockEnd;
   tr = ar[0]*Real.Data[k] - ai[0]*Imag.Data[k];
   ti = ar[0]*Imag.Data[k] + ai[0]*Real.Data[k];

   Real.Data[k] = Real.Data[j] - tr;
   Imag.Data[k] = Imag.Data[j] - ti;

   Real.Data[j] += tr;
   Imag.Data[j] += ti;
   }
   }
   BlockEnd = BlockSize;
   }

   if(InvertFlag)
   {
   double denom = (double)FFTSize;
   for(i=0; i   {
   Real.Data[i] /= denom;
   Imag.Data[i] /= denom;
   }
   }

   if(ReplaceFlag)
   {
   for(i=0; i   {
   rData[i] = Real.Data[i];
   iData[i] = Imag.Data[i];
   }
   }
}

The Signal Processing Forum will coming soon.

Create Date : 15 มิถุนายน 2552

2 comments

Last Update : 17 มิถุนายน 2552 16:56:24 น.

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ขอรับไปลองศึกษาดูนะครับ

โดย: EDENAS 17 มิถุนายน 2552 17:53:10 น.

สุดยอดครับพี่ติ

โดย: ต๊อก IP: 61.7.171.5 19 มิถุนายน 2552 19:03:14 น.