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Diffstat (limited to 'trunk/codecs/lpc10/lpfilt.c')
| -rw-r--r-- | trunk/codecs/lpc10/lpfilt.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/trunk/codecs/lpc10/lpfilt.c b/trunk/codecs/lpc10/lpfilt.c new file mode 100644 index 000000000..375528921 --- /dev/null +++ b/trunk/codecs/lpc10/lpfilt.c @@ -0,0 +1,125 @@ +/* + +$Log$ +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 22:31:35 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 lpfilt_(real *inbuf, real *lpbuf, integer *len, integer *nsamp); +#endif + +/* *********************************************************************** */ + +/* LPFILT 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 22:31:35 jaf + * Initial revision + * */ +/* Revision 1.3 1996/03/15 16:53:49 jaf */ +/* Just put comment header in standard form. */ + +/* Revision 1.2 1996/03/12 23:58:06 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 14:47:44 jaf */ +/* Initial revision */ + + +/* *********************************************************************** */ + +/* 31 Point Equiripple FIR Low-Pass Filter */ +/* Linear phase, delay = 15 samples */ + +/* Passband: ripple = 0.25 dB, cutoff = 800 Hz */ +/* Stopband: atten. = 40. dB, cutoff = 1240 Hz */ + +/* Inputs: */ +/* LEN - Length of speech buffers */ +/* NSAMP - Number of samples to filter */ +/* INBUF - Input speech buffer */ +/* Indices len-nsamp-29 through len are read. */ +/* Output: */ +/* LPBUF - Low passed speech buffer (must be different array than INBUF) */ +/* Indices len+1-nsamp through len are written. */ + +/* This subroutine has no local state. */ + +/* Subroutine */ int lpfilt_(real *inbuf, real *lpbuf, integer *len, integer * + nsamp) +{ + /* System generated locals */ + integer i__1; + + /* Local variables */ + integer j; + real t; + +/* Arguments */ +/* Parameters/constants */ +/* Local variables that need not be saved */ +/* Local state */ +/* None */ + /* Parameter adjustments */ + --lpbuf; + --inbuf; + + /* Function Body */ + i__1 = *len; + for (j = *len + 1 - *nsamp; j <= i__1; ++j) { + t = (inbuf[j] + inbuf[j - 30]) * -.0097201988f; + t += (inbuf[j - 1] + inbuf[j - 29]) * -.0105179986f; + t += (inbuf[j - 2] + inbuf[j - 28]) * -.0083479648f; + t += (inbuf[j - 3] + inbuf[j - 27]) * 5.860774e-4f; + t += (inbuf[j - 4] + inbuf[j - 26]) * .0130892089f; + t += (inbuf[j - 5] + inbuf[j - 25]) * .0217052232f; + t += (inbuf[j - 6] + inbuf[j - 24]) * .0184161253f; + t += (inbuf[j - 7] + inbuf[j - 23]) * 3.39723e-4f; + t += (inbuf[j - 8] + inbuf[j - 22]) * -.0260797087f; + t += (inbuf[j - 9] + inbuf[j - 21]) * -.0455563702f; + t += (inbuf[j - 10] + inbuf[j - 20]) * -.040306855f; + t += (inbuf[j - 11] + inbuf[j - 19]) * 5.029835e-4f; + t += (inbuf[j - 12] + inbuf[j - 18]) * .0729262903f; + t += (inbuf[j - 13] + inbuf[j - 17]) * .1572008878f; + t += (inbuf[j - 14] + inbuf[j - 16]) * .2247288674f; + t += inbuf[j - 15] * .250535965f; + lpbuf[j] = t; + } + return 0; +} /* lpfilt_ */ + |