#include "f2c.h"
Include dependency graph for preemp.c:
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Functions | |
| int | preemp_ (real *inbuf, real *pebuf, integer *nsamp, real *coef, real *z__) |
Function Documentation
◆ preemp_()
Definition at line 82 of file preemp.c.
84{
85 /* System generated locals */
86 integer i__1;
87
88 /* Local variables */
89 real temp;
90 integer i__;
91
92/* Arguments */
93/* Local variables */
94
95/* None of these need to have their values saved from one */
96/* invocation to the next. */
97
98/* Logically, this subroutine computes the output sequence */
99/* pebuf(1:nsamp) defined by: */
100
101/* pebuf(i) = inbuf(i) - coef * inbuf(i-1) */
102
103/* where inbuf(0) is defined by the value of z given as input to */
104/* this subroutine. */
105
106/* What is this filter's frequency response and phase response? */
107
108/* Why is this filter applied to the speech? */
109
110/* Could it be more efficient to apply multiple filters */
111/* simultaneously, by combining them into one equivalent filter? */
112
113/* Are there ever cases when "factoring" one high-order filter into
114*/
115/* multiple smaller-order filter actually reduces the number of */
116/* arithmetic operations needed to perform them? */
117/* When I first read this subroutine, I didn't understand why the */
118/* variable temp was used. It seemed that the statements in the do
119*/
120/* loop could be replaced with the following: */
121
122/* pebuf(i) = inbuf(i) - coef * z */
123/* z = inbuf(i) */
124
125/* The reason for temp is so that even if pebuf and inbuf are the */
126/* same arrays in memory (i.e., they are aliased), then this */
127/* subroutine will still work correctly. I didn't realize this */
128/* until seeing the comment after PEBUF above that says "(can be */
129/* equal to INBUF)". */
130 /* Parameter adjustments */
131 --pebuf;
132 --inbuf;
133
134 /* Function Body */
135 i__1 = *nsamp;
136 for (i__ = 1; i__ <= i__1; ++i__) {
137 temp = inbuf[i__] - *coef * *z__;
138 *z__ = inbuf[i__];
139 pebuf[i__] = temp;
140/* L10: */
141 }
142 return 0;
143} /* preemp_ */
static int inbuf(struct baseio *bio, FILE *fi)
utility used by inchar(), for base_encode()
Definition utils.c:590
References inbuf().
Referenced by analys_().
