/* $Log$ Revision 1.16 2004/06/26 03:50:14 markster Merge source cleanups (bug #1911) Revision 1.15 2003/09/19 01:20:22 markster Code cleanups (bug #66) Revision 1.2 2003/09/19 01:20:22 markster Code cleanups (bug #66) 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 22:31:53 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 ivfilt_(real *lpbuf, real *ivbuf, integer *len, integer *nsamp, real *ivrc); #endif /* ********************************************************************* */ /* IVFILT Version 48 */ /* $Log$ * Revision 1.16 2004/06/26 03:50:14 markster * Merge source cleanups (bug #1911) * * Revision 1.15 2003/09/19 01:20:22 markster * Code cleanups (bug #66) * * Revision 1.2 2003/09/19 01:20:22 markster * Code cleanups (bug #66) * * 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 22:31:53 jaf * Initial revision * */ /* Revision 1.3 1996/03/15 21:36:29 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 1996/03/13 00:01:00 jaf */ /* Comments added explaining that none of the local variables of this */ /* subroutine need to be saved from one invocation to the next. */ /* Revision 1.1 1996/02/07 14:47:34 jaf */ /* Initial revision */ /* ********************************************************************* */ /* 2nd order inverse filter, speech is decimated 4:1 */ /* Input: */ /* LEN - Length of speech buffers */ /* NSAMP - Number of samples to filter */ /* LPBUF - Low pass filtered speech buffer */ /* Indices LEN-NSAMP-7 through LEN read. */ /* Output: */ /* IVBUF - Inverse filtered speech buffer */ /* Indices LEN-NSAMP+1 through LEN written. */ /* IVRC - Inverse filter reflection coefficients (for voicing) */ /* Indices 1 and 2 both written (also read, but only after writing). */ /* This subroutine has no local state. */ /* Subroutine */ int ivfilt_(real *lpbuf, real *ivbuf, integer *len, integer * nsamp, real *ivrc) { /* System generated locals */ integer i__1; /* Local variables */ integer i__, j, k; real r__[3], pc1, pc2; /* Arguments */ /* Local variables that need not be saved */ /* Local state */ /* None */ /* Calculate Autocorrelations */ /* Parameter adjustments */ --ivbuf; --lpbuf; --ivrc; /* Function Body */ for (i__ = 1; i__ <= 3; ++i__) { r__[i__ - 1] = 0.f; k = (i__ - 1) << 2; i__1 = *len; for (j = (i__ << 2) + *len - *nsamp; j <= i__1; j += 2) { r__[i__ - 1] += lpbuf[j] * lpbuf[j - k]; } } /* Calculate predictor coefficients */ pc1 = 0.f; pc2 = 0.f; ivrc[1] = 0.f; ivrc[2] = 0.f; if (r__[0] > 1e-10f) { ivrc[1] = r__[1] / r__[0]; ivrc[2] = (r__[2] - ivrc[1] * r__[1]) / (r__[0] - ivrc[1] * r__[1]); pc1 = ivrc[1] - ivrc[1] * ivrc[2]; pc2 = ivrc[2]; } /* Inverse filter LPBUF into IVBUF */ i__1 = *len; for (i__ = *len + 1 - *nsamp; i__ <= i__1; ++i__) { ivbuf[i__] = lpbuf[i__] - pc1 * lpbuf[i__ - 4] - pc2 * lpbuf[i__ - 8]; } return 0; } /* ivfilt_ */