anaFilter.h File Reference

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Functions
void	anaFilter (float *In, float *a, int len, float *Out, float *mem)

Function Documentation

anaFilter()

void anaFilter	(	float *	In,
		float *	a,
		int	len,
		float *	Out,
		float *	mem
	)

Definition at line 20 of file anaFilter.c.

References a, len(), and LPC_FILTERORDER.

Referenced by iLBC_encode().

 {
 int i, j;
 float *po, *pi, *pm, *pa;

 po = Out;

 /* Filter first part using memory from past */

 for (i=0; i<LPC_FILTERORDER; i++) {
 pi = &In[i];
 pm = &mem[LPC_FILTERORDER-1];
 pa = a;
 *po=0.0;





 for (j=0; j<=i; j++) {
 *po+=(*pa++)*(*pi--);
 }
 for (j=i+1; j<LPC_FILTERORDER+1; j++) {

 *po+=(*pa++)*(*pm--);
 }
 po++;
 }

 /* Filter last part where the state is entirely
 in the input vector */

 for (i=LPC_FILTERORDER; i<len; i++) {
 pi = &In[i];
 pa = a;
 *po=0.0;
 for (j=0; j<LPC_FILTERORDER+1; j++) {
 *po+=(*pa++)*(*pi--);
 }
 po++;
 }

 /* Update state vector */

 memcpy(mem, &In[len-LPC_FILTERORDER],
 LPC_FILTERORDER*sizeof(float));
 }