// CICFilter.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <memory.h>
//試驗一個16bit的CIC濾波器溢出的情況
void CIC_Filter(int nDataCnt,short *pBuf,short *pOut,int R);

int main(int argc, char* argv[])
{
	printf("CIC Filter Test!\n");

	short x[1024];
	short y[1024];

	for(int i=0;i<1024;i++)
	{
		x[i]=511;		//10bit輸入時，最大正數(shù)
		x[i]=-512;	//10bit輸入時，最大負數(shù)
		//x[i]=1023;	//11bit輸入時，最大正數(shù)
		//x[i]=-1024;	//11bit輸入時，最大負數(shù)
	}

	memset(y,0,1024*sizeof(short));
	CIC_Filter(1024,x,y,4);

	return 0;
}


void CIC_Filter(int nDataCnt,short *pBuf,short *pOut,int R)
{
	short intg1=0;
	short intg2=0;
	short intg3=0;
	short dump1=0;
	short dump2=0;
	short dump3=0;

	int i;
	short *pIntg3=new short[nDataCnt];
	short *pDump1=new short[nDataCnt];
	short *pDump2=new short[nDataCnt];

	memset(pIntg3,0,nDataCnt);
	memset(pDump1,0,nDataCnt);
	memset(pDump2,0,nDataCnt);

	//積分環(huán)節(jié)
	for(i=0;i<nDataCnt;i++)
	{
		pIntg3[i]=intg3;

		intg3 +=intg2;
		intg2 +=intg1;
		intg1 +=pBuf[i];		
	}

	//梳狀濾波器環(huán)節(jié)
	for(i=R;i<nDataCnt;i++)
	{	
		pDump1[i]=dump1;
		dump1=pIntg3[i] - pIntg3[i-R];		
	}

	for(i=R;i<nDataCnt;i++)
	{	
		pDump2[i]=dump2;
		dump2 = pDump1[i] - pDump1[i-R];		
	}

	for(i=R;i<nDataCnt;i++)
	{			
		pOut[i]=dump3;
		dump3 =pDump2[i] - pDump2[i-R];		
	}


	delete [] pIntg3;
	delete [] pDump1;
	delete [] pDump2;
	
}