patch-2.0.35 linux/drivers/net/soundmodem/sm_psk4800.c

• Lines: 419
• Date: Mon Jul 13 13:47:31 1998
• Orig file: v2.0.34/linux/drivers/net/soundmodem/sm_psk4800.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.0.34/linux/drivers/net/soundmodem/sm_psk4800.c linux/drivers/net/soundmodem/sm_psk4800.c
@@ -0,0 +1,418 @@
+/*****************************************************************************/
+
+/*
+ *	sm_psk4800.c  -- soundcard radio modem driver, 4800 baud 8PSK modem
+ *
+ *	Copyright (C) 1997  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.
+ *
+ */
+
+#include "sm.h"
+#include "sm_tbl_psk4800.h"
+
+/* --------------------------------------------------------------------- */
+
+#define DESCRAM_TAP1 0x20000
+#define DESCRAM_TAP2 0x01000
+#define DESCRAM_TAP3 0x00001
+
+#define DESCRAM_TAPSH1 17
+#define DESCRAM_TAPSH2 12
+#define DESCRAM_TAPSH3 0
+
+#define SCRAM_TAP1 0x20000 /* X^17 */
+#define SCRAM_TAPN 0x00021 /* X^0+X^5 */
+
+#define SCRAM_SHIFT 17
+
+/* --------------------------------------------------------------------- */
+
+struct demod_state_psk48 {
+	/*
+	 * input mixer and lowpass
+	 */
+	short infi[PSK48_RXF_LEN/2], infq[PSK48_RXF_LEN/2];
+	unsigned int downmixer;
+	int ovrphase;
+	short magi, magq;
+	/*
+	 * sampling instant recovery
+	 */
+	int pwrhist[5];
+	unsigned int s_phase;
+	int cur_sync;
+	/*
+	 * phase recovery
+	 */
+	short cur_phase_dev;
+	short last_ph_err;
+	unsigned short pskph;
+	unsigned int phase;
+	unsigned short last_pskph;
+	unsigned char cur_raw, last_raw, rawbits;
+	/*
+	 * decoding
+	 */
+	unsigned int shreg;
+	unsigned long descram;
+	unsigned int bit_pll;
+	unsigned char last_sample;
+	unsigned int dcd_shreg;
+	int dcd_sum0, dcd_sum1, dcd_sum2;
+	unsigned int dcd_time;
+};
+
+struct mod_state_psk48 {
+	unsigned char txbits[PSK48_TXF_NUMSAMPLES];
+	unsigned short txphase;
+	unsigned int shreg;
+	unsigned long scram;
+	const short *tbl;
+	unsigned int txseq;
+};
+
+/* --------------------------------------------------------------------- */
+
+static void modulator_4800_u8(struct sm_state *sm, unsigned char *buf, unsigned int buflen)
+{
+	struct mod_state_psk48 *st = (struct mod_state_psk48 *)(&sm->m);
+	int i, j;
+	int si, sq;
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (!st->txseq++) {
+			memmove(st->txbits+1, st->txbits, 
+				sizeof(st->txbits)-sizeof(st->txbits[0]));
+			for (i = 0; i < 3; i++) {
+				if (st->shreg <= 1)
+					st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+				st->scram = (st->scram << 1) |
+					(st->shreg & 1);
+				st->shreg >>= 1;
+				if (st->scram & SCRAM_TAP1)
+					st->scram ^= SCRAM_TAPN;
+			}
+			j = (st->scram >> (SCRAM_SHIFT+3)) & 7;
+			st->txbits[0] -= (j ^ (j >> 1));
+			st->txbits[0] &= 7;
+			st->tbl = psk48_tx_table;
+		}
+		if (st->txseq >= PSK48_TXF_OVERSAMPLING)
+			st->txseq = 0;
+		for (j = si = sq = 0; j < PSK48_TXF_NUMSAMPLES; j++, st->tbl += 16) {
+			si += st->tbl[st->txbits[j]];
+			sq += st->tbl[st->txbits[j]+8];
+		}
+		*buf = ((si*COS(st->txphase)+ sq*SIN(st->txphase)) >> 23) + 0x80;
+		st->txphase = (st->txphase + PSK48_PHASEINC) & 0xffffu;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void modulator_4800_s16(struct sm_state *sm, short *buf, unsigned int buflen)
+{
+	struct mod_state_psk48 *st = (struct mod_state_psk48 *)(&sm->m);
+	int i, j;
+	int si, sq;
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (!st->txseq++) {
+			memmove(st->txbits+1, st->txbits, 
+				sizeof(st->txbits)-sizeof(st->txbits[0]));
+			for (i = 0; i < 3; i++) {
+				if (st->shreg <= 1)
+					st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+				st->scram = (st->scram << 1) |
+					(st->shreg & 1);
+				st->shreg >>= 1;
+				if (st->scram & SCRAM_TAP1)
+					st->scram ^= SCRAM_TAPN;
+			}
+			j = (st->scram >> (SCRAM_SHIFT+3)) & 7;
+			st->txbits[0] -= (j ^ (j >> 1));
+			st->txbits[0] &= 7;
+			st->tbl = psk48_tx_table;
+		}
+		if (st->txseq >= PSK48_TXF_OVERSAMPLING)
+			st->txseq = 0;
+		for (j = si = sq = 0; j < PSK48_TXF_NUMSAMPLES; j++, st->tbl += 16) {
+			si += st->tbl[st->txbits[j]];
+			sq += st->tbl[st->txbits[j]+8];
+		}
+		*buf = (si*COS(st->txphase)+ sq*SIN(st->txphase)) >> 15;
+		st->txphase = (st->txphase + PSK48_PHASEINC) & 0xffffu;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static __inline__ unsigned short tbl_atan(short q, short i)
+{
+	short tmp;
+	unsigned short argoffs = 0;
+
+	if (i == 0 && q == 0)
+		return 0;
+	switch (((q < 0) << 1) | (i < 0)) {
+	case 0:
+		break;
+	case 1:
+		tmp = q;
+		q = -i;
+		i = tmp;
+		argoffs = 0x4000;
+		break;
+	case 3:
+		q = -q;
+		i = -i;
+		argoffs = 0x8000;
+		break;
+	case 2:
+		tmp = -q;
+		q = i;
+		i = tmp;
+		argoffs = 0xc000;
+		break;
+	}
+	if (q > i) {
+		tmp = i / q * ATAN_TABLEN;
+		return (argoffs+0x4000-atan_tab[((i<<15)/q*ATAN_TABLEN>>15)])
+			&0xffffu;
+	}
+	return (argoffs+atan_tab[((q<<15)/i*ATAN_TABLEN)>>15])&0xffffu;
+}
+
+#define ATAN(q,i) tbl_atan(q, i)
+
+/* --------------------------------------------------------------------- */
+
+static void demod_psk48_baseband(struct sm_state *sm, struct demod_state_psk48 *st,
+				 short vali, short valq)
+{
+	int i, j;
+
+	st->magi = vali;
+	st->magq = valq;
+	memmove(st->pwrhist+1, st->pwrhist, 
+		sizeof(st->pwrhist)-sizeof(st->pwrhist[0]));
+	st->pwrhist[0] = st->magi * st->magi +
+		st->magq * st->magq;
+	st->cur_sync = ((st->pwrhist[4] >> 2) > st->pwrhist[2] && 
+			(st->pwrhist[0] >> 2) > st->pwrhist[2] &&
+			st-> pwrhist[3] > st->pwrhist[2] && 
+			st->pwrhist[1] > st->pwrhist[2]);
+	st->s_phase &= 0xffff;
+	st->s_phase += PSK48_SPHASEINC;
+	st->dcd_shreg <<= 1;
+	if (st->cur_sync) {
+		if (st->s_phase >= (0x8000 + 5*PSK48_SPHASEINC/2))
+			st->s_phase -= PSK48_SPHASEINC/6;
+		else
+			st->s_phase += PSK48_SPHASEINC/6;
+		st->dcd_sum0 = 4*hweight8(st->dcd_shreg & 0xf8)-
+			hweight16(st->dcd_shreg & 0x1f00);
+	}
+	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->s_phase < 0x10000)
+		return;
+	/*
+	 * sample one constellation
+	 */
+	st->last_pskph = st->pskph;
+	st->pskph = (ATAN(st->magq, st->magi)-
+			       st->phase) & 0xffffu;
+	st->last_ph_err = (st->pskph & 0x1fffu) - 0x1000;
+	st->phase += st->last_ph_err/16;
+	st->last_raw = st->cur_raw;
+	st->cur_raw = ((st->pskph >> 13) & 7);
+	i = (st->cur_raw - st->last_raw) & 7;
+	st->rawbits = i ^ (i >> 1) ^ (i >> 2);
+	st->descram = (st->descram << 3) | (st->rawbits);
+	hdlcdrv_channelbit(&sm->hdrv, st->descram & 4);
+	hdlcdrv_channelbit(&sm->hdrv, st->descram & 2);
+	hdlcdrv_channelbit(&sm->hdrv, st->descram & 1);
+	i = (((st->descram >> DESCRAM_TAPSH1) & 7) ^
+	     ((st->descram >> DESCRAM_TAPSH2) & 7) ^
+	     ((st->descram >> DESCRAM_TAPSH3) & 7));
+ 	for (j = 4; j; j >>= 1) {
+		st->shreg >>= 1;
+		st->shreg |= (!!(i & j)) << 16;
+		if (st->shreg & 1) {
+			hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
+			st->shreg = 0x10000;
+		}
+	}
+
+#if 0
+	st->dcd_shreg <<= 1;
+	st->bit_pll += 0x4000;
+	curbit = (*buf >= 0x80);
+	if (st->last_sample ^ curbit) {
+		st->dcd_shreg |= 1;
+		st->bit_pll += pll_corr
+			[st->bit_pll < 0xa000];
+		st->dcd_sum0 += 8 * 
+			hweight8(st->dcd_shreg & 0x0c) - 
+				!!(st->dcd_shreg & 0x10);
+	}
+	st->last_sample = curbit;
+	hdlcdrv_channelbit(&sm->hdrv, st->last_sample);
+	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 &= 0xffffu;
+		st->descram = (st->descram << 1) | curbit;
+		descx = st->descram ^ (st->descram >> 1);
+			descx ^= ((descx >> DESCRAM_TAPSH1) ^
+				  (descx >> DESCRAM_TAPSH2));
+			st->shreg >>= 1;
+			st->shreg |= (!(descx & 1)) << 16;
+			if (st->shreg & 1) {
+				hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
+				st->shreg = 0x10000;
+			}
+			diag_trigger(sm);
+	}
+	diag_add_one(sm, ((short)(*buf - 0x80)) << 8);
+#endif
+	
+	diag_trigger(sm);
+	diag_add_constellation(sm, (vali*COS(st->phase)+ valq*SIN(st->phase)) >> 13, 
+			       (valq*COS(st->phase) - vali*SIN(st->phase)) >> 13);
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_4800_u8(struct sm_state *sm, const unsigned char *buf, unsigned int buflen)
+{
+	struct demod_state_psk48 *st = (struct demod_state_psk48 *)(&sm->d);
+	int i, si, sq;
+	const short *coeff;
+
+	for (; buflen > 0; buflen--, buf++) {
+		memmove(st->infi+1, st->infi, 
+			sizeof(st->infi)-sizeof(st->infi[0]));
+		memmove(st->infq+1, st->infq, 
+			sizeof(st->infq)-sizeof(st->infq[0]));
+		si = *buf;
+		si &= 0xff;
+		si -= 128;
+		diag_add_one(sm, si << 8);
+		st->infi[0] = (si * COS(st->downmixer))>>7;
+		st->infq[0] = (si * SIN(st->downmixer))>>7;
+		st->downmixer = (st->downmixer-PSK48_PHASEINC)&0xffffu;
+		for (i = si = sq = 0, coeff = psk48_rx_coeff; i < (PSK48_RXF_LEN/2); 
+		     i++, coeff += 2) {
+			si += st->infi[i] * (*coeff);
+			sq += st->infq[i] * (*coeff);
+		}
+		demod_psk48_baseband(sm, st, si >> 15, sq >> 15);
+		for (i = si = sq = 0, coeff = psk48_rx_coeff + 1; i < (PSK48_RXF_LEN/2); 
+		     i++, coeff += 2) {
+			si += st->infi[i] * (*coeff);
+			sq += st->infq[i] * (*coeff);
+		}
+		demod_psk48_baseband(sm, st, si >> 15, sq >> 15);
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_4800_s16(struct sm_state *sm, const short *buf, unsigned int buflen)
+{
+	struct demod_state_psk48 *st = (struct demod_state_psk48 *)(&sm->d);
+	int i, si, sq;
+	const short *coeff;
+
+	for (; buflen > 0; buflen--, buf++) {
+		memmove(st->infi+1, st->infi, 
+			sizeof(st->infi)-sizeof(st->infi[0]));
+		memmove(st->infq+1, st->infq, 
+			sizeof(st->infq)-sizeof(st->infq[0]));
+		si = *buf;
+		diag_add_one(sm, si);
+		st->infi[0] = (si * COS(st->downmixer))>>15;
+		st->infq[0] = (si * SIN(st->downmixer))>>15;
+		st->downmixer = (st->downmixer-PSK48_PHASEINC)&0xffffu;
+		for (i = si = sq = 0, coeff = psk48_rx_coeff; i < (PSK48_RXF_LEN/2); 
+		     i++, coeff += 2) {
+			si += st->infi[i] * (*coeff);
+			sq += st->infq[i] * (*coeff);
+		}
+		demod_psk48_baseband(sm, st, si >> 15, sq >> 15);
+		for (i = si = sq = 0, coeff = psk48_rx_coeff + 1; i < (PSK48_RXF_LEN/2); 
+		     i++, coeff += 2) {
+			si += st->infi[i] * (*coeff);
+			sq += st->infq[i] * (*coeff);
+		}
+		demod_psk48_baseband(sm, st, si >> 15, sq >> 15);
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void mod_init_4800(struct sm_state *sm)
+{
+	struct mod_state_psk48 *st = (struct mod_state_psk48 *)(&sm->m);
+
+	st->scram = 1;
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demod_init_4800(struct sm_state *sm)
+{
+	struct demod_state_psk48 *st = (struct demod_state_psk48 *)(&sm->d);
+
+	st->dcd_time = 120;
+	st->dcd_sum0 = 2;	
+}
+
+/* --------------------------------------------------------------------- */
+
+const struct modem_tx_info sm_psk4800_tx = {
+	"psk4800", sizeof(struct mod_state_psk48), 
+	PSK48_SAMPLERATE, 4800,
+	modulator_4800_u8, modulator_4800_s16, mod_init_4800
+};
+
+const struct modem_rx_info sm_psk4800_rx = {
+	"psk4800", sizeof(struct demod_state_psk48), 
+	PSK48_SAMPLERATE, 4800, 1, PSK48_TXF_OVERSAMPLING, 
+	demodulator_4800_u8, demodulator_4800_s16, demod_init_4800
+};
+
+/* --------------------------------------------------------------------- */