159 lines
4.1 KiB
C
159 lines
4.1 KiB
C
/*
|
|
* Implementation of the V34 phase 2
|
|
*
|
|
* Copyright (c) 1999,2000 Fabrice Bellard.
|
|
*
|
|
* This code is released under the GNU General Public License version
|
|
* 2. Please read the file COPYING to know the exact terms of the
|
|
* license.
|
|
*
|
|
* This implementation is totally clean room. It was written by
|
|
* reading the V34 specification and by using basic signal processing
|
|
* knowledge.
|
|
*/
|
|
#include "lm.h"
|
|
#include "v34priv.h"
|
|
|
|
#define DEBUG
|
|
|
|
#define INFO_SYNC 0x72
|
|
|
|
/* send the v34 info0 sequence */
|
|
void V34_send_info0(V34State *s, int ack)
|
|
{
|
|
u8 buf[48], *p, *q;
|
|
int crc;
|
|
|
|
p = buf;
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
put_bits(&p, 8, INFO_SYNC); /* sync word */
|
|
|
|
put_bits(&p, 1, 1); /* symbol rate 2743 supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 2800 supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 3429 supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 3000, low carrier supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 3000, high carrier supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 3200, low carrier supported ? */
|
|
put_bits(&p, 1, 1); /* symbol rate 3200, high carrier supported ? */
|
|
|
|
put_bits(&p, 1, 1); /* symbol rate 3429 disallowed ? */
|
|
put_bits(&p, 1, 1); /* can power reduce ? */
|
|
put_bits(&p, 3, 5); /* difference between emit & receive sym rate */
|
|
put_bits(&p, 1, 0); /* from CME modem ? */
|
|
put_bits(&p, 1, 0); /* reserved by ITU */
|
|
put_bits(&p, 2, 0); /* tx clock source: 0=internal */
|
|
put_bits(&p, 1, ack); /* ack reception */
|
|
|
|
/* crc */
|
|
crc = calc_crc(buf + 12, p - (buf + 12));
|
|
put_bits(&p, 16, crc);
|
|
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
|
|
for(q=buf;q<p;q++) {
|
|
put_sym(s, buf[i], 0);
|
|
}
|
|
}
|
|
|
|
/* send the v34 info1c sequence */
|
|
void V34_send_info1c(V34State *s)
|
|
{
|
|
u8 buf[109], *p;
|
|
int crc;
|
|
|
|
p = buf;
|
|
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
put_bits(&p, 8, INFO_SYNC); /* sync word */
|
|
|
|
put_bits(&p, 3, 1); /* minimum power reduction (XXX) */
|
|
put_bits(&p, 3, 1); /* additional power reduction (XXX) */
|
|
put_bits(&p, 7, 0); /* length of MD sequence (35 ms incr) */
|
|
|
|
for(i=0;i<6;i++) {
|
|
/* for each symbol speed (increasing order) */
|
|
put_bits(&p, 1, 0); /* use high carrier ? (XXX) */
|
|
put_bits(&p, 4, 0); /* pre emphasis filter (XXX) */
|
|
put_bits(&p, 4, 12); /* projected data rate (XXX) */
|
|
}
|
|
|
|
put_bits(&p, 10, 0); /* frequency offset (XXX) */
|
|
|
|
/* crc */
|
|
crc = calc_crc(buf + 12, p - (buf + 12));
|
|
put_bits(&p, 16, crc);
|
|
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
}
|
|
|
|
/* send the v34 info1a sequence */
|
|
void V34_send_info1a(V34State *s)
|
|
{
|
|
u8 buf[70], *p;
|
|
int crc;
|
|
|
|
p = buf;
|
|
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
put_bits(&p, 8, INFO_SYNC); /* sync word */
|
|
|
|
put_bits(&p, 3, 1); /* minimum power reduction (XXX) */
|
|
put_bits(&p, 3, 1); /* additional power reduction (XXX) */
|
|
put_bits(&p, 7, 0); /* length of MD sequence (35 ms incr) */
|
|
|
|
put_bits(&p, 1, 0); /* high carrier used (XXX) */
|
|
put_bits(&p, 4, 0); /* pre emphasis filter (XXX) */
|
|
put_bits(&p, 4, 12); /* proj max data rate (XXX) */
|
|
|
|
put_bits(&p, 3, 4); /* sym rate ans->cal (XXX : 3200) */
|
|
put_bits(&p, 3, 4); /* sym rate cal->ans (XXX : 3200) */
|
|
|
|
put_bits(&p, 10, 0); /* frequency offset (XXX) */
|
|
|
|
/* crc */
|
|
crc = calc_crc(buf + 12, p - (buf + 12));
|
|
put_bits(&p, 16, crc);
|
|
|
|
put_bits(&p, 4, 0xf); /* fill bits */
|
|
}
|
|
|
|
|
|
void V34_send_L1(V34State *s, int rep)
|
|
{
|
|
static char ph[25] = {
|
|
/* 150 */ 1,-1, 1, 1,
|
|
/* 750 */ 1, 0, 1, 0,
|
|
/*1350 */ 1, 1,-1, 0,
|
|
/*1950 */ 1, 1,-1, 0,
|
|
/*2550 */ 1,-1, 1,-1,
|
|
/*3150 */ -1,-1,-1, 1,
|
|
/*3750 */ 1 };
|
|
|
|
for(n=0;n<rep;n++) {
|
|
for(i=0;i<25;i++) {
|
|
if (ph[i]) {
|
|
put_sym(s, i * 150 + 150, ph[i]);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
int V34P2_process(V34State *s, s16 *output, s16 *input, int nb_samples)
|
|
{
|
|
/* modulation */
|
|
switch(s->state) {
|
|
case V34_P2_INFO0_SEND:
|
|
V34_send_info0(
|
|
|
|
}
|
|
|
|
/* demodulation */
|
|
switch(s->state) {
|
|
case V34_P2_INFO0_SEND:
|
|
|
|
|
|
}
|
|
}
|
|
|