impulse.c

语音CELP压缩解压源代码（C语音)

/**************************************************************************
*
* ROUTINE
*               impulse
*
* FUNCTION
*               compute impulse response with direct form filter
*		exclusive of adaptive code book contribution
*
* SYNOPSIS
*               subroutine impulse(l)
*
*   formal
*
*                       data    I/O
*       name            type    type    function
*       -------------------------------------------------------------------
*       l               int     i       impulse response length
*
*   external
*                       data    I/O
*       name            type    type    function
*       -------------------------------------------------------------------
*	no		int	i
*	fc[]		float	i
*	h[]		float	i/o
*	gamma2		float	i
*
***************************************************************************
*
* Global Variables
*
*
*	SPECTRUM VARIABLE:
*	d5	real	auxiliary array
*
****************************************************************************
* CALLED BY
*
*	csub
*
* CALLS
*
*	bwexp	setr	polefilt
*
**************************************************************************/
#include "ccsub.h"
extern int no;
extern float fc[MAXNO+1], h[MAXLP], gamma2;

impulse(l)
int l;
{
  float d5[MAXNO+1], fctemp[MAXNO + 1];

  setr(l, 0.0, h);
  h[0] = 1.0;
  setr(no + 1, 0.0, d5);
  bwexp(gamma2, fc, fctemp, no);
  polefilt(fctemp, no, d5, h, l);

}