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Diffstat (limited to '1.2-netsec/codecs/lpc10/preemp.c')
| -rw-r--r-- | 1.2-netsec/codecs/lpc10/preemp.c | 144 |
1 files changed, 0 insertions, 144 deletions
diff --git a/1.2-netsec/codecs/lpc10/preemp.c b/1.2-netsec/codecs/lpc10/preemp.c deleted file mode 100644 index cc27f7baa..000000000 --- a/1.2-netsec/codecs/lpc10/preemp.c +++ /dev/null @@ -1,144 +0,0 @@ -/* - -$Log$ -Revision 1.15 2004/06/26 03:50:14 markster -Merge source cleanups (bug #1911) - -Revision 1.14 2003/02/12 13:59:15 matteo -mer feb 12 14:56:57 CET 2003 - -Revision 1.1.1.1 2003/02/12 13:59:15 matteo -mer feb 12 14:56:57 CET 2003 - -Revision 1.2 2000/01/05 08:20:39 markster -Some OSS fixes and a few lpc changes to make it actually work - - * Revision 1.1 1996/08/19 22:30:58 jaf - * Initial revision - * - -*/ - -/* -- translated by f2c (version 19951025). - You must link the resulting object file with the libraries: - -lf2c -lm (in that order) -*/ - -#include "f2c.h" - -#ifdef P_R_O_T_O_T_Y_P_E_S -extern int preemp_(real *inbuf, real *pebuf, integer *nsamp, real *coef, real *z__); -#endif - -/* ******************************************************************* */ - -/* PREEMP Version 55 */ - -/* $Log$ - * Revision 1.15 2004/06/26 03:50:14 markster - * Merge source cleanups (bug #1911) - * -/* Revision 1.14 2003/02/12 13:59:15 matteo -/* mer feb 12 14:56:57 CET 2003 -/* -/* Revision 1.1.1.1 2003/02/12 13:59:15 matteo -/* mer feb 12 14:56:57 CET 2003 -/* -/* Revision 1.2 2000/01/05 08:20:39 markster -/* Some OSS fixes and a few lpc changes to make it actually work -/* - * Revision 1.1 1996/08/19 22:30:58 jaf - * Initial revision - * */ -/* Revision 1.3 1996/03/14 23:16:29 jaf */ -/* Just added a few comments about which array indices of the arguments */ -/* are used, and mentioning that this subroutine has no local state. */ - -/* Revision 1.2 1996/03/11 23:23:34 jaf */ -/* Added a bunch of comments to an otherwise simple subroutine. */ - -/* Revision 1.1 1996/02/07 14:48:48 jaf */ -/* Initial revision */ - - -/* ******************************************************************* */ - -/* Preemphasize speech with a single-zero filter. */ -/* (When coef = .9375, preemphasis is as in LPC43.) */ - -/* Inputs: */ -/* NSAMP - Number of samples to filter */ -/* INBUF - Input speech buffer */ -/* Indices 1 through NSAMP are read. */ -/* COEF - Preemphasis coefficient */ -/* Input/Output: */ -/* Z - Filter state */ -/* Output: */ -/* PEBUF - Preemphasized speech buffer (can be equal to INBUF) */ -/* Indices 1 through NSAMP are modified. */ - -/* This subroutine has no local state. */ - -/* Subroutine */ int preemp_(real *inbuf, real *pebuf, integer *nsamp, real * - coef, real *z__) -{ - /* System generated locals */ - integer i__1; - - /* Local variables */ - real temp; - integer i__; - -/* Arguments */ -/* Local variables */ - -/* None of these need to have their values saved from one */ -/* invocation to the next. */ - -/* Logically, this subroutine computes the output sequence */ -/* pebuf(1:nsamp) defined by: */ - -/* pebuf(i) = inbuf(i) - coef * inbuf(i-1) */ - -/* where inbuf(0) is defined by the value of z given as input to */ -/* this subroutine. */ - -/* What is this filter's frequency response and phase response? */ - -/* Why is this filter applied to the speech? */ - -/* Could it be more efficient to apply multiple filters */ -/* simultaneously, by combining them into one equivalent filter? */ - -/* Are there ever cases when "factoring" one high-order filter into -*/ -/* multiple smaller-order filter actually reduces the number of */ -/* arithmetic operations needed to perform them? */ -/* When I first read this subroutine, I didn't understand why the */ -/* variable temp was used. It seemed that the statements in the do -*/ -/* loop could be replaced with the following: */ - -/* pebuf(i) = inbuf(i) - coef * z */ -/* z = inbuf(i) */ - -/* The reason for temp is so that even if pebuf and inbuf are the */ -/* same arrays in memory (i.e., they are aliased), then this */ -/* subroutine will still work correctly. I didn't realize this */ -/* until seeing the comment after PEBUF above that says "(can be */ -/* equal to INBUF)". */ - /* Parameter adjustments */ - --pebuf; - --inbuf; - - /* Function Body */ - i__1 = *nsamp; - for (i__ = 1; i__ <= i__1; ++i__) { - temp = inbuf[i__] - *coef * *z__; - *z__ = inbuf[i__]; - pebuf[i__] = temp; -/* L10: */ - } - return 0; -} /* preemp_ */ - |