FreeCalypso > hg > efr-experiments

annotate src/syn_filt.c @ 8:8b17df8f6340 default tip

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
add README
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 17 Apr 2024 17:30:25 +0000
parents 56410792419a
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 /*************************************************************************
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 *
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 * FUNCTION: Syn_filt:
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 *
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 * PURPOSE: Perform synthesis filtering through 1/A(z).
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 *
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 *************************************************************************/
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 #include "typedef.h"
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 #include "basic_op.h"
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 #include "count.h"
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 /* m = LPC order == 10 */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 #define m 10
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 void Syn_filt (
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 Word16 a[], /* (i) : a[m+1] prediction coefficients (m=10) */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 Word16 x[], /* (i) : input signal */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 Word16 y[], /* (o) : output signal */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 Word16 lg, /* (i) : size of filtering */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 Word16 mem[], /* (i/o) : memory associated with this filtering. */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22 Word16 update /* (i) : 0=no update, 1=update of memory. */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 )
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 Word16 i, j;
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 Word32 s;
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 Word16 tmp[80]; /* This is usually done by memory allocation (lg+m) */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28 Word16 *yy;
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 /* Copy mem[] to yy[] */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 yy = tmp; move16 ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 for (i = 0; i < m; i++)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 *yy++ = mem[i]; move16 ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 /* Do the filtering. */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 for (i = 0; i < lg; i++)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43 s = L_mult (x[i], a[0]);
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 for (j = 1; j <= m; j++)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 s = L_msu (s, a[j], yy[-j]);
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 s = L_shl (s, 3);
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 *yy++ = round (s); move16 ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52 for (i = 0; i < lg; i++)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 y[i] = tmp[i + m]; move16 ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57 /* Update of memory if update==1 */
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 test ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 if (update != 0)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62 for (i = 0; i < m; i++)
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 {
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64 mem[i] = y[lg - m + i]; move16 ();
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 }
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67 return;
56410792419a src: original EFR source from ETSI
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68 }