Initial import

git-svn-id: http://moon:8086/svn/software/trunk/libsrc/fir@1 b431acfa-c32f-4a4a-93f1-934dc6c82436
2014-07-19 07:44:42 +00:00
commit 0179c510fe
12 changed files with 1436 additions and 0 deletions
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+/*************************************************************************/
+/* fir.c
+/*************************************************************************/
+#include <stdio.h>
+#include <malloc.h>
+#include "math.h"
+#include "fir.h"
+
+/*************************************************************************/
+/* Global Variables
+/*************************************************************************/
+void Sinc(float *pY, int M, float s, float f, int len)
+{
+	int i, m;
+	float x,h;
+
+	m = (len-1)/2;
+	for (i=1; i <= m; i++)
+	{
+		x = (float)(pi*f*i);
+		h = (float)cos(i*0.5*pi/m);
+		pY[m+i] = h*s*(float)sin(x)/x;
+		pY[m-i] = pY[m+i];
+	}
+
+	pY[m] = s;
+}
+
+void FIRCalcDCRemovalCoeff(struct _sFIRCoeff *pCoeff, int N)
+{
+	int n;
+	float k = 1.f/N;
+
+	FIRInit(pCoeff, 0, N);
+
+	for (n=0; n < N; n++)
+		pCoeff->pB[n] = -k;
+
+	pCoeff->pB[0] += 1.f;
+}
+
+void FIR(struct _sFIRCoeff *pCoeff, float *xn, float *yn, int order, int len)
+{
+	int i, n;
+	float *pB, *pX;
+
+	for (i=0; i<len; i++)
+	{
+		pB = &pCoeff->pB[order-1];
+		pX = &pCoeff->pX[order-1];
+		pCoeff->pX[0] = xn[i];
+
+		yn[i] = 0;
+		for (n=0; n < order; n++)
+		{
+			yn[i] += *(pB--) * *pX; 
+			*(pX) = *(pX-1);
+			pX--;
+		}
+	}
+}
+
+void FIRInit(struct _sFIRCoeff *pCoeff, float *pB, int order)
+{
+	int n;
+	if (pB)
+	{
+		for(n=0; n < order; n++)
+		{
+			pCoeff->pB[n] = pB[n];
+			pCoeff->pX[n] = 0;
+		}
+	}
+	else
+	{
+		for(n=0; n < order; n++)
+		{
+			pCoeff->pB[n] = 0;
+			pCoeff->pX[n] = 0;
+		}
+	}
+}
+
+void FIRAlloc(struct _sFIRCoeff *pCoeff, int order)
+{
+	pCoeff->pB = malloc(order*sizeof(float));
+	pCoeff->pX = malloc(order*sizeof(float));
+}
+
+void FIRFree(struct _sFIRCoeff *pCoeff)
+{
+	free(pCoeff->pB);
+	free(pCoeff->pX);
+}