lpc.h

2400bps MELP语音编解码源程序。

/*

2.4 kbps MELP Proposed Federal Standard speech coder

Fixed-point C code, version 1.0

Copyright (c) 1998, Texas Instruments, Inc.  

Texas Instruments has intellectual property rights on the MELP
algorithm.  The Texas Instruments contact for licensing issues for
commercial and non-government use is William Gordon, Director,
Government Contracts, Texas Instruments Incorporated, Semiconductor
Group (phone [phone]).

The fixed-point version of the voice codec Mixed Excitation Linear
Prediction (MELP) is based on specifications on the C-language software
simulation contained in GSM 06.06 which is protected by copyright and
is the property of the European Telecommunications Standards Institute
(ETSI). This standard is available from the ETSI publication office
tel. [phone]. ETSI has granted a license to United States
Department of Defense to use the C-language software simulation contained
in GSM 06.06 for the purposes of the development of a fixed-point
version of the voice codec Mixed Excitation Linear Prediction (MELP).
Requests for authorization to make other use of the GSM 06.06 or
otherwise distribute or modify them need to be addressed to the ETSI
Secretariat fax: [phone].

*/
/* 
   lpc.h     LPC include file.
*/


#ifndef _lpc_h
#define _lpc_h_

/* better names */
#define lpc_autocorr               lpc_acor
#define lpc_bw_expand              lpc_bwex
#define lpc_lag_window             lpc_lagw
#define lpc_schur                  lpc_schr
#define lpc_clamp                  lpc_clmp
#define lpc_synthesis              lpc_syn

#define LPC_WINDOW_EXPONENTIAL 0
#define LPC_WINDOW_GAUSSIAN    1


/* autocorrelation routine */
void lpc_acor(Shortword input[],Shortword win_cof[],
		   Shortword r[],Shortword hf_correction,
		   Shortword lag_win,Shortword order,Shortword npts);
Longword lpc_aejw(Shortword *a,Shortword w, Shortword p);
Shortword lpc_bwex(Shortword *a, Shortword *aw, Shortword gamma, Shortword p);
Shortword lpc_clmp(Shortword *w, Shortword delta, Shortword p);
Shortword lpc_schr(Shortword *r, Shortword *a, Shortword *k_tmp, 
		   Shortword p);
Shortword lpc_refl2pred(Shortword *k,Shortword *a,Shortword p);
Shortword lpc_pred2lsp(Shortword *a,Shortword *w,Shortword p);
Shortword lpc_pred2refl(Shortword *a,Shortword *k,Shortword p);
Shortword lpc_lsp2pred(Shortword *w,Shortword *a,Shortword p);
Shortword lpc_syn(Shortword *x,Shortword *y,Shortword *a,Shortword p,
		  Shortword n);

#endif