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|
/*****************************************************************************/
/*
* sm_hapn4800.c -- soundcard radio modem driver, 4800 baud HAPN modem
*
* Copyright (C) 1996 Thomas Sailer (sailer@ife.ee.ethz.ch)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Please note that the GPL allows you to use the driver, NOT the radio.
* In order to use the radio, you need a license from the communications
* authority of your country.
*
*
* This module implements a (hopefully) HAPN (Hamilton Area Packet
* Network) compatible 4800 baud modem.
* The HAPN modem uses kind of "duobinary signalling" (not really,
* duobinary signalling gives ... 0 0 -1 0 1 0 0 ... at the sampling
* instants, whereas HAPN signalling gives ... 0 0 -1 1 0 0 ..., see
* Proakis, Digital Communications).
* The code is untested. It is compatible with itself (i.e. it can decode
* the packets it sent), but I could not test if it is compatible with
* any "real" HAPN modem, since noone uses it in my region of the world.
* Feedback therefore welcome.
*/
#include "sm.h"
#include "sm_tbl_hapn4800.h"
/* --------------------------------------------------------------------- */
struct demod_state_hapn48 {
unsigned int shreg;
unsigned int bit_pll;
unsigned char last_bit;
unsigned char last_bit2;
unsigned int dcd_shreg;
int dcd_sum0, dcd_sum1, dcd_sum2;
unsigned int dcd_time;
int inphist[5];
int lvlhi, lvllo;
};
struct mod_state_hapn48 {
unsigned int shreg;
unsigned char tx_bit;
};
/* --------------------------------------------------------------------- */
static void modulator_hapn4800_10(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct mod_state_hapn48 *st = (struct mod_state_hapn48 *)(&sm->m);
int j;
const unsigned char *cp;
for (; buflen >= 10; buflen -= 10) {
if (st->shreg <= 1)
st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
st->tx_bit = ((st->tx_bit << 1) |
(st->tx_bit & 1));
st->tx_bit ^= (!(st->shreg & 1));
st->shreg >>= 1;
cp = hapn48_txfilt_10 + (st->tx_bit & 0xf);
for (j = 0; j < 10; j++, cp += 0x10)
*buf++ = *cp;
}
}
/* --------------------------------------------------------------------- */
static void modulator_hapn4800_8(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct mod_state_hapn48 *st = (struct mod_state_hapn48 *)(&sm->m);
int j;
const unsigned char *cp;
for (; buflen >= 8; buflen -= 8) {
if (st->shreg <= 1)
st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
st->tx_bit = (st->tx_bit << 1) | (st->tx_bit & 1);
st->tx_bit ^= !(st->shreg & 1);
st->shreg >>= 1;
cp = hapn48_txfilt_8 + (st->tx_bit & 0xf);
for (j = 0; j < 8; j++, cp += 0x10)
*buf++ = *cp;
}
}
/* --------------------------------------------------------------------- */
static void modulator_hapn4800_pm10(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct mod_state_hapn48 *st = (struct mod_state_hapn48 *)(&sm->m);
int j;
const unsigned char *cp;
for (; buflen >= 10; buflen -= 10) {
if (st->shreg <= 1)
st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
st->tx_bit = ((st->tx_bit << 1) |
(st->tx_bit & 1));
st->tx_bit ^= (!(st->shreg & 1));
st->shreg >>= 1;
cp = hapn48_txfilt_pm10 + (st->tx_bit & 0xf);
for (j = 0; j < 10; j++, cp += 0x10)
*buf++ = *cp;
}
}
/* --------------------------------------------------------------------- */
static void modulator_hapn4800_pm8(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct mod_state_hapn48 *st = (struct mod_state_hapn48 *)(&sm->m);
int j;
const unsigned char *cp;
for (; buflen >= 8; buflen -= 8) {
if (st->shreg <= 1)
st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
st->tx_bit = (st->tx_bit << 1) | (st->tx_bit & 1);
st->tx_bit ^= !(st->shreg & 1);
st->shreg >>= 1;
cp = hapn48_txfilt_pm8 + (st->tx_bit & 0xf);
for (j = 0; j < 8; j++, cp += 0x10)
*buf++ = *cp;
}
}
/* --------------------------------------------------------------------- */
static void demodulator_hapn4800_10(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct demod_state_hapn48 *st = (struct demod_state_hapn48 *)(&sm->d);
static const int pll_corr[2] = { -0x800, 0x800 };
int curst, cursync;
for (; buflen > 0; buflen--, buf++) {
st->inphist[4] = st->inphist[3];
st->inphist[3] = st->inphist[2];
st->inphist[2] = st->inphist[1];
st->inphist[1] = st->inphist[0];
st->inphist[0] = ((int)(*buf)-0x80) << 8;
st->lvlhi = (st->lvlhi * 65309) >> 16; /* decay */
st->lvllo = (st->lvllo * 65309) >> 16; /* decay */
if (st->inphist[2] > st->lvlhi)
st->lvlhi = st->inphist[2];
if (st->inphist[2] < st->lvllo)
st->lvllo = st->inphist[2];
if (buflen & 1)
st->dcd_shreg <<= 1;
st->bit_pll += 0x199a;
curst = cursync = 0;
if (st->inphist[2] > st->lvlhi >> 1) {
curst = 1;
cursync = (st->inphist[2] > st->inphist[1] &&
st->inphist[2] > st->inphist[3] &&
st->inphist[2] > st->inphist[0] &&
st->inphist[2] > st->inphist[4]);
} else if (st->inphist[2] < st->lvllo >> 1) {
curst = -1;
cursync = (st->inphist[2] < st->inphist[1] &&
st->inphist[2] < st->inphist[3] &&
st->inphist[2] < st->inphist[0] &&
st->inphist[2] < st->inphist[4]);
}
if (cursync) {
st->dcd_shreg |= cursync;
st->bit_pll += pll_corr[((st->bit_pll - 0x8000u) & 0xffffu) < 0x8ccdu];
st->dcd_sum0 += 16 * hweight32(st->dcd_shreg & 0x18c6318c) -
hweight32(st->dcd_shreg & 0xe739ce70);
}
hdlcdrv_channelbit(&sm->hdrv, cursync);
if ((--st->dcd_time) <= 0) {
hdlcdrv_setdcd(&sm->hdrv, (st->dcd_sum0 +
st->dcd_sum1 +
st->dcd_sum2) < 0);
st->dcd_sum2 = st->dcd_sum1;
st->dcd_sum1 = st->dcd_sum0;
st->dcd_sum0 = 2; /* slight bias */
st->dcd_time = 240;
}
if (st->bit_pll >= 0x10000) {
st->bit_pll &= 0xffff;
st->last_bit2 = st->last_bit;
if (curst < 0)
st->last_bit = 0;
else if (curst > 0)
st->last_bit = 1;
st->shreg >>= 1;
st->shreg |= ((st->last_bit ^ st->last_bit2 ^ 1) & 1) << 16;
if (st->shreg & 1) {
hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
st->shreg = 0x10000;
}
diag_trigger(sm);
}
diag_add_one(sm, st->inphist[2]);
}
}
/* --------------------------------------------------------------------- */
static void demodulator_hapn4800_8(struct sm_state *sm, unsigned char *buf, int buflen)
{
struct demod_state_hapn48 *st = (struct demod_state_hapn48 *)(&sm->d);
static const int pll_corr[2] = { -0x800, 0x800 };
int curst, cursync;
for (; buflen > 0; buflen--, buf++) {
st->inphist[4] = st->inphist[3];
st->inphist[3] = st->inphist[2];
st->inphist[2] = st->inphist[1];
st->inphist[1] = st->inphist[0];
st->inphist[0] = ((int)(*buf)-0x80) << 8;
st->lvlhi = (st->lvlhi * 65309) >> 16; /* decay */
st->lvllo = (st->lvllo * 65309) >> 16; /* decay */
if (st->inphist[2] > st->lvlhi)
st->lvlhi = st->inphist[2];
if (st->inphist[2] < st->lvllo)
st->lvllo = st->inphist[2];
if (buflen & 1)
st->dcd_shreg <<= 1;
st->bit_pll += 0x2000;
curst = cursync = 0;
if (st->inphist[2] > st->lvlhi >> 1) {
curst = 1;
cursync = (st->inphist[2] > st->inphist[1] &&
st->inphist[2] > st->inphist[3] &&
st->inphist[2] > st->inphist[0] &&
st->inphist[2] > st->inphist[4]);
} else if (st->inphist[2] < st->lvllo >> 1) {
curst = -1;
cursync = (st->inphist[2] < st->inphist[1] &&
st->inphist[2] < st->inphist[3] &&
st->inphist[2] < st->inphist[0] &&
st->inphist[2] < st->inphist[4]);
}
if (cursync) {
st->dcd_shreg |= cursync;
st->bit_pll += pll_corr[((st->bit_pll - 0x8000u) & 0xffffu) < 0x9000u];
st->dcd_sum0 += 16 * hweight32(st->dcd_shreg & 0x44444444) -
hweight32(st->dcd_shreg & 0xbbbbbbbb);
}
hdlcdrv_channelbit(&sm->hdrv, cursync);
if ((--st->dcd_time) <= 0) {
hdlcdrv_setdcd(&sm->hdrv, (st->dcd_sum0 +
st->dcd_sum1 +
st->dcd_sum2) < 0);
st->dcd_sum2 = st->dcd_sum1;
st->dcd_sum1 = st->dcd_sum0;
st->dcd_sum0 = 2; /* slight bias */
st->dcd_time = 240;
}
if (st->bit_pll >= 0x10000) {
st->bit_pll &= 0xffff;
st->last_bit2 = st->last_bit;
if (curst < 0)
st->last_bit = 0;
else if (curst > 0)
st->last_bit = 1;
st->shreg >>= 1;
st->shreg |= ((st->last_bit ^ st->last_bit2 ^ 1) & 1) << 16;
if (st->shreg & 1) {
hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
st->shreg = 0x10000;
}
diag_trigger(sm);
}
diag_add_one(sm, st->inphist[2]);
}
}
/* --------------------------------------------------------------------- */
static void demod_init_hapn4800(struct sm_state *sm)
{
struct demod_state_hapn48 *st = (struct demod_state_hapn48 *)(&sm->d);
st->dcd_time = 120;
st->dcd_sum0 = 2;
}
/* --------------------------------------------------------------------- */
const struct modem_tx_info sm_hapn4800_8_tx = {
"hapn4800", sizeof(struct mod_state_hapn48),
38400, 4800, 8, modulator_hapn4800_8, NULL
};
const struct modem_rx_info sm_hapn4800_8_rx = {
"hapn4800", sizeof(struct demod_state_hapn48),
38400, 4800, 8, 8, demodulator_hapn4800_8, demod_init_hapn4800
};
/* --------------------------------------------------------------------- */
const struct modem_tx_info sm_hapn4800_10_tx = {
"hapn4800", sizeof(struct mod_state_hapn48),
48000, 4800, 10,
modulator_hapn4800_10, NULL
};
const struct modem_rx_info sm_hapn4800_10_rx = {
"hapn4800", sizeof(struct demod_state_hapn48),
48000, 4800, 10, 10, demodulator_hapn4800_10, demod_init_hapn4800
};
/* --------------------------------------------------------------------- */
const struct modem_tx_info sm_hapn4800_pm8_tx = {
"hapn4800pm", sizeof(struct mod_state_hapn48),
38400, 4800, 8, modulator_hapn4800_pm8, NULL
};
const struct modem_rx_info sm_hapn4800_pm8_rx = {
"hapn4800pm", sizeof(struct demod_state_hapn48),
38400, 4800, 8, 8, demodulator_hapn4800_8, demod_init_hapn4800
};
/* --------------------------------------------------------------------- */
const struct modem_tx_info sm_hapn4800_pm10_tx = {
"hapn4800pm", sizeof(struct mod_state_hapn48),
48000, 4800, 10,
modulator_hapn4800_pm10, NULL
};
const struct modem_rx_info sm_hapn4800_pm10_rx = {
"hapn4800pm", sizeof(struct demod_state_hapn48),
48000, 4800, 10, 10, demodulator_hapn4800_10, demod_init_hapn4800
};
/* --------------------------------------------------------------------- */
|
