- initial import

git-svn-id: http://moon:8086/svn/mips@1 a8ebac50-d88d-4704-bea3-6648445a41b3
2014-07-20 15:01:37 +00:00
commit 26291bca3d
1549 changed files with 3997969 additions and 0 deletions
@@ -0,0 +1,167 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define		pi		3.14159265359
+#define		datasize        1024
+
+double COSINE[datasize], SINE[datasize];       /* Twiddle tables           */
+/* RData[] is the real component, CData[] is the imaginary component */
+double RData[datasize], CData[datasize];
+
+/********************************************************/
+/* MAKE_TWIDDLE_TABLE                                   */
+/* - Generates a FFT twiddle table.                     */
+/********************************************************/
+void make_twiddle_table(int Inputs)
+{
+int    i;
+int    size = (Inputs / 2);
+double arg1, arg2;
+   arg1 = (2.0 * pi / (double)Inputs);
+   for (i = 1; i <= Inputs; i++) {
+	   arg2 = (double)(i - size) * arg1;
+	   COSINE[i-1] = cos(arg2);
+	   SINE[i-1]   = sin(arg2);
+   }
+}
+
+/****************************************/
+/* FFT                                  */
+/****************************************/
+void fft(double RData[datasize], double CData[datasize], int Inputs)
+{
+int    i, z, zz, j, j2, j3, k, r, d, st;
+int    nd2, nml, arg, twf;
+double tempr, tempc, c, s;
+   for (i = 0; i < Inputs; i+=2) {
+	   RData[i] = -1.0 * RData[i];
+	   CData[i] = -1.0 * CData[i];
+   }
+   if (Inputs ==  16) st = 4;
+   if (Inputs ==  32) st = 5;
+   if (Inputs ==  64) st = 6;
+   if (Inputs == 128) st = 7;
+   if (Inputs == 256) st = 8;
+   if (Inputs == 512) st = 9;
+   if (Inputs == 1024) st = 10;
+   j = 1;
+   for (z = 1; z < Inputs; z++) {
+	   if (z < j) {
+		  tempr      = RData[j-1];
+		  RData[j-1] = RData[z-1];
+		  RData[z-1] = tempr;
+		  tempc      = CData[j-1];
+		  CData[j-1] = CData[z-1];
+		  CData[z-1] = tempc;
+       }
+	   k = (Inputs / 2);
+	   while (k < j) {
+		  j -= k;
+		  k  = (k / 2);
+       }
+	   j += k;
+   }
+   for (z = 1; z <= st; z++) {
+	   r   = 1;
+	   for (i = 1; i <= z; i++) r = (r * 2);
+	   d   = (r / 2);
+	   arg = (Inputs / r);
+	   for (zz = 1; zz <= d; zz++) {
+		   twf = (Inputs/4-1) + (arg * (zz-1));
+		   c   = COSINE[twf];
+	   s   = SINE[twf];
+		   k   = zz;
+	   while (k <= Inputs) {
+			  j2 = (k + d) - 1;
+			  j3 = (k - 1);
+			  tempr     = (RData[j2] * c) + (CData[j2] * s);
+			  tempc     = (CData[j2] * c) - (RData[j2] * s);
+			  RData[j2] = (RData[j3] - tempr);
+	      CData[j2] = (CData[j3] - tempc);
+			  RData[j3] = (RData[j3] + tempr);
+	      CData[j3] = (CData[j3] + tempc);
+	      k += r;
+		   }
+       }
+   }
+}
+
+/****************************************/
+/* MODULUS                              */
+/* - Calculates modulus of data.        */
+/****************************************/
+void modulus(double rdata[datasize], double cdata[datasize], int Inputs)
+{
+int    i;
+double temp;
+	for (i = 0; i < Inputs; i++) {
+		temp = sqrt(rdata[i] * rdata[i] + cdata[i] * cdata[i]);
+		rdata[i] = temp;
+		cdata[i] = 0.0;
+	}
+}
+
+/********************************************************/
+/* MAIN                                                 */
+/********************************************************/
+void main(void)
+{
+/* Pixels can be 32, 64, 128, 256, or 512 depends on data set size */
+
+int k;
+double fk;
+int n;
+int N = 32;
+float kf = 2;
+float f;
+float fmax;
+float fa;
+float W;
+
+/********************************************************/
+printf ("\nFast-Fourier-Transformation eines Sinussignals.");
+printf ("\nAnzahl der St�tzstellen: ");
+scanf ("%d",&N);
+printf ("Frequenz des Sinussignals [Hz]: ");
+scanf ("%f",&f);
+printf ("Maximale Frequenz des Nutzsignals [Hz] : ");
+scanf ("%f",&fmax);
+while (1) {
+printf ("Abtastfrequenz [Hz]: ");
+scanf ("%f",&fa);
+if (fa < 2*fmax)
+	{ printf ("Verletzung des Abtasttheorems nach Nyquist.\nBitte Eingabe wiederholen\n"); continue ;}
+	break;
+}
+kf = fa / fmax;
+W = 2.0 * pi * f;
+
+/********************************************************/
+
+for (n=0; n < datasize; n++)
+  { RData[n] = (double) sin (W*n/fa);
+    CData[n] = 0;
+}
+make_twiddle_table(N/2);
+
+/* Call FFT routine with complex data */
+	fft(RData, CData, N);
+
+/* Call modulus routine - optional */
+	modulus(RData, CData, N);
+
+printf ("\n\n%d-Punkt FFT",N);
+printf ("\nf = %g Hz\nH”chste Frequenz = %g Hz",f,fmax);
+printf ("\nAbtastfrequenz = %g Hz\n\nFrequenzspektrum S(f):",fa);
+
+for ( k=0; k <= N/2; k++)
+    {  printf ( "\n%g Hz = %f",(double)k*fa/(N),2*RData[k]/N);
+
+
+}
+printf ("\n\nEnde");
+
+}
+