www.pudn.com > CryptoPhone-src-031122.zip > con_adap.c

/* Copyright 2001,2002,2003 NAH6 
 * All Rights Reserved 
 * 
 * Parts Copyright DoD, Parts Copyright Starium 
 * 
 */ 
          /*LINTLIBRARY*/ 
          /*PROTOLIB1*/ 
 
#include  
#include  
#include "main.h" 
#include "delay.h" 
#include "con_adap.h" 
 
#define STRING_MATCH 0 
 
/************************************************************************* 
* 
* ROUTINE 
*               ConstructAdaptCW 
* 
* FUNCTION 
*               Adaptive VQ (n-taps, where n = 0, ..., 3) 
*		"self-excited" or "vq" or "adaptive code book" 
* 
* SYNOPSIS 
*		ConstructAdaptCW(residual, ResLen, AdaptCB, AdaptCBLen, 
*			AdaptGain, AdaptDelay, Type) 
*   formal  
* 
*                       data    I/O 
*       name            type    type    function 
*       ------------------------------------------------------------------- 
*	residual	float	i/o	Data segement/Filtered data segment 
*	ResLen		int	 i	Dimension of residual 
*	AdaptCB		float	 i	Adaptive Codebook 
*	AdaptCBLen	int	 i	Dimension of Adaptive codebook 
*	AdaptDelay	float	 i	Adaptive codebook delay  
*	AdaptGain	float	 i	Adaptive codebook gain 
*	Type		char	 i	Type 'long' calls ldelay.f, the 
*					delay routine using long  
*					interpolation windows.  Type 'short' 
*					calls delay.f, the short delay 
*					routine. 
*========================================================================== 
*        
* USAGE 
* 
*    Adaptive code book (pitch) synthesis routine: 
* 
*    1) For lags < frame size:  gain-shape adaptive code book VQ 
* 
*    2) For lags => frame size this is equivalent to a pitch synthesis "filter" 
* 
*                              -[b(1)-1]        -b(1)        -[b(1)+1] 
*       H(z) =  1 /  1 + b(2) z         + b(3) z     + b(4) z 
* 
*========================================================================== 
*	 
* REFERENCES 
* 
*	Singhal & Atal, Improving Performance of Multi-Pulse LPC Coders at 
*	Low Bit Rates, ICASSP, 1984. 
* 
*	Rose & Barnwell.  The Self Excited Vocoder-An Alternate Approach 
*	to Toll Quality at 4800 bps, ICASSP, 1986, pp. 453-456. 
* 
*	Kleijn, Krasinski and Ketchum, Improved Speech Quality and 
*	Efficient Vector Quantization in SELP, ICASSP, 1988. 
* 
***************************************************************************/ 
void ConstructAdaptCW( 
float	residual[RES_LEN], 
int	ResLen, 
float	AdaptCB[MAX_ABUF_LEN], 
int	AdaptCBLen, 
float	AdaptGain, 
float	AdaptDelay, 
char	*Type) 
{ 
int	k, start, m; 
float	frac; 
int	i; 
float	buf[MAX_A_LEN]; 
 
/*  Initialize variables */ 
	k = AdaptCBLen - ResLen; 
	start = k + 1; 
	m = (int)(AdaptDelay); 
	frac = AdaptDelay - m; 
 
/*  Update codebook */ 
	for(i=0; i .0001)	{ 
	  if (strcmp(Type, "long") == STRING_MATCH)	{ /* if they match */ 
	    delay(AdaptCB, AdaptCBLen, start, ResLen, frac, m, -20, 19, 5, buf); 
	  } 
	  else	{ 
	    delay(AdaptCB, AdaptCBLen, start, ResLen, frac, m, -4, 3, 5, buf); 
	  } 
	  for(i=0; i