patch-2.0.35 linux/drivers/net/soundmodem/sm_afsk2666.c

• Lines: 357
• Date: Mon Jul 13 13:47:31 1998
• Orig file: v2.0.34/linux/drivers/net/soundmodem/sm_afsk2666.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.0.34/linux/drivers/net/soundmodem/sm_afsk2666.c linux/drivers/net/soundmodem/sm_afsk2666.c
@@ -0,0 +1,356 @@
+/*****************************************************************************/
+
+/*
+ *	sm_afsk2666.c  -- soundcard radio modem driver, 2666 baud AFSK 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_afsk2666.h"
+
+/* --------------------------------------------------------------------- */
+
+struct demod_state_afsk26 {
+	unsigned int shreg;
+	unsigned long descram;
+	int dem_sum[8];
+	int dem_sum_mean;
+	int dem_cnt;
+	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_afsk26 {
+	unsigned int shreg;
+	unsigned long scram;
+	unsigned int bit_pll;
+	unsigned int phinc;
+	unsigned int tx_seq;
+};
+
+/* --------------------------------------------------------------------- */
+
+#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 */
+
+/* --------------------------------------------------------------------- */
+
+static void modulator_2666_u8(struct sm_state *sm, unsigned char *buf, unsigned int buflen)
+{
+	struct mod_state_afsk26 *st = (struct mod_state_afsk26 *)(&sm->m);
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (!st->tx_seq++) {
+			if (st->shreg <= 1)
+				st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+			st->scram = ((st->scram << 1) | (st->scram & 1));
+			st->scram ^= (!(st->shreg & 1));
+			st->shreg >>= 1;
+			if (st->scram & (SCRAM_TAP1 << 1))
+				st->scram ^= SCRAM_TAPN << 1;
+			st->phinc = afsk26_carfreq[!(st->scram & (SCRAM_TAP1 << 2))];
+		}
+		if (st->tx_seq >= 6)
+			st->tx_seq = 0;
+		*buf = OFFSCOS(st->bit_pll);
+		st->bit_pll += st->phinc;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void modulator_2666_s16(struct sm_state *sm, short *buf, unsigned int buflen)
+{
+	struct mod_state_afsk26 *st = (struct mod_state_afsk26 *)(&sm->m);
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (!st->tx_seq++) {
+			if (st->shreg <= 1)
+				st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+			st->scram = ((st->scram << 1) | (st->scram & 1));
+			st->scram ^= (!(st->shreg & 1));
+			st->shreg >>= 1;
+			if (st->scram & (SCRAM_TAP1 << 1))
+				st->scram ^= SCRAM_TAPN << 1;
+			st->phinc = afsk26_carfreq[!(st->scram & (SCRAM_TAP1 << 2))];
+		}
+		if (st->tx_seq >= 6)
+			st->tx_seq = 0;
+		*buf = COS(st->bit_pll);
+		st->bit_pll += st->phinc;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+extern __inline__ int convolution12_u8(const unsigned char *st, const int *coeff, int csum)
+{
+	int sum = -0x80 * csum;
+	
+	sum += (st[0] * coeff[0]);
+	sum += (st[-1] * coeff[1]);
+	sum += (st[-2] * coeff[2]);
+	sum += (st[-3] * coeff[3]);
+	sum += (st[-4] * coeff[4]);
+	sum += (st[-5] * coeff[5]);
+	sum += (st[-6] * coeff[6]);
+	sum += (st[-7] * coeff[7]);
+	sum += (st[-8] * coeff[8]);
+	sum += (st[-9] * coeff[9]);
+	sum += (st[-10] * coeff[10]);
+	sum += (st[-11] * coeff[11]);
+
+	return sum;
+}
+
+extern __inline__ int convolution12_s16(const short *st, const int *coeff, int csum)
+{
+	int sum = 0;
+	
+	sum += (st[0] * coeff[0]);
+	sum += (st[-1] * coeff[1]);
+	sum += (st[-2] * coeff[2]);
+	sum += (st[-3] * coeff[3]);
+	sum += (st[-4] * coeff[4]);
+	sum += (st[-5] * coeff[5]);
+	sum += (st[-6] * coeff[6]);
+	sum += (st[-7] * coeff[7]);
+	sum += (st[-8] * coeff[8]);
+	sum += (st[-9] * coeff[9]);
+	sum += (st[-10] * coeff[10]);
+	sum += (st[-11] * coeff[11]);
+
+	sum >>= 8;
+	return sum;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#if 0
+static int binexp(unsigned int i)
+{
+	int ret = 31;
+	
+	if (!i)
+		return 0;
+	if (i < 0x10000LU) {
+		i <<= 16;
+		ret -= 16;
+	}
+	if (i < 0x1000000LU) {
+		i <<= 8;
+		ret -= 8;
+	}
+	if (i < 0x10000000LU) {
+		i <<= 4;
+		ret -= 4;
+	}
+	if (i < 0x40000000LU) {
+		i <<= 2;
+		ret -= 2;
+	}
+	if (i < 0x80000000LU)
+		ret -= 1;
+	return ret;
+}
+
+static const sqrt_tab[16] = {
+	00000, 16384, 23170, 28378, 32768, 36636, 40132, 43348,
+	46341, 49152, 51811, 54340, 56756, 59073, 61303, 63455
+};
+
+
+static unsigned int int_sqrt_approx(unsigned int i)
+{
+	unsigned int j;
+
+	if (i < 16)
+		return sqrt_tab[i] >> 14;
+	j = binexp(i) >> 1;
+	i >>= (j * 2 - 2);
+      	return (sqrt_tab[i & 0xf] << j) >> 15;
+}
+#endif
+
+/* --------------------------------------------------------------------- */
+
+extern unsigned int est_pwr(int i, int q)
+{
+	unsigned int ui = abs(i);
+	unsigned int uq = abs(q);
+
+	if (uq > ui) {
+		unsigned int tmp;
+		tmp = ui;
+		ui = uq;
+		uq = tmp;
+	}
+	if (uq > (ui >> 1))
+		return 7*(ui>>3) + 9*(uq>>4);
+	else
+		return ui + (uq>>2);
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demod_one_sample(struct sm_state *sm, struct demod_state_afsk26 *st, int curval,
+			     int loi, int loq, int hii, int hiq)
+{
+	static const int pll_corr[2] = { -0xa00, 0xa00 };
+	unsigned char curbit;
+	unsigned int descx;
+	int val;
+
+	/* 
+	 * estimate power
+	 */
+	val = est_pwr(hii, hiq) - est_pwr(loi, loq);
+	/*
+	 * estimate center value
+	 */
+	st->dem_sum[0] += val >> 8;
+	if ((++st->dem_cnt) >= 256) {
+		st->dem_cnt = 0;
+		st->dem_sum_mean = (st->dem_sum[0]+st->dem_sum[1]+
+				    st->dem_sum[2]+st->dem_sum[3]+
+				    st->dem_sum[4]+st->dem_sum[5]+
+				    st->dem_sum[6]+st->dem_sum[7]) >> 3;
+		memmove(st->dem_sum+1, st->dem_sum, 
+			sizeof(st->dem_sum)-sizeof(st->dem_sum[0]));
+		st->dem_sum[0] = 0;
+	}
+	/*
+	 * decision and bit clock regen
+	 */
+	val -= st->dem_sum_mean;
+	diag_add(sm, curval, val);
+	
+	st->dcd_shreg <<= 1;
+	st->bit_pll += 0x1555;
+	curbit = (val > 0);
+	if (st->last_sample ^ curbit) {
+		st->dcd_shreg |= 1;
+		st->bit_pll += pll_corr[st->bit_pll < (0x8000+0x1555)];
+		st->dcd_sum0 += 4*hweight8(st->dcd_shreg & 0x1e) -
+			hweight16(st->dcd_shreg & 0xfe00);
+	}
+	st->last_sample = curbit;
+	hdlcdrv_channelbit(&sm->hdrv, curbit);
+	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 = 400;
+	}
+	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);
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_2666_u8(struct sm_state *sm, const unsigned char *buf, unsigned int buflen)
+{
+	struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
+
+	for (; buflen > 0; buflen--, buf++) {
+		demod_one_sample(sm, st, (*buf-0x80)<<8,
+				 convolution12_u8(buf, afsk26_dem_tables[0][0].i, AFSK26_DEM_SUM_I_0_0),
+				 convolution12_u8(buf, afsk26_dem_tables[0][0].q, AFSK26_DEM_SUM_Q_0_0),
+				 convolution12_u8(buf, afsk26_dem_tables[0][1].i, AFSK26_DEM_SUM_I_0_1),
+				 convolution12_u8(buf, afsk26_dem_tables[0][1].q, AFSK26_DEM_SUM_Q_0_1));
+		demod_one_sample(sm, st,  (*buf-0x80)<<8,
+				 convolution12_u8(buf, afsk26_dem_tables[1][0].i, AFSK26_DEM_SUM_I_1_0),
+				 convolution12_u8(buf, afsk26_dem_tables[1][0].q, AFSK26_DEM_SUM_Q_1_0),
+				 convolution12_u8(buf, afsk26_dem_tables[1][1].i, AFSK26_DEM_SUM_I_1_1),
+				 convolution12_u8(buf, afsk26_dem_tables[1][1].q, AFSK26_DEM_SUM_Q_1_1));
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_2666_s16(struct sm_state *sm, const short *buf, unsigned int buflen)
+{
+	struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
+
+	for (; buflen > 0; buflen--, buf++) {
+		demod_one_sample(sm, st, *buf,
+				 convolution12_s16(buf, afsk26_dem_tables[0][0].i, AFSK26_DEM_SUM_I_0_0),
+				 convolution12_s16(buf, afsk26_dem_tables[0][0].q, AFSK26_DEM_SUM_Q_0_0),
+				 convolution12_s16(buf, afsk26_dem_tables[0][1].i, AFSK26_DEM_SUM_I_0_1),
+				 convolution12_s16(buf, afsk26_dem_tables[0][1].q, AFSK26_DEM_SUM_Q_0_1));
+		demod_one_sample(sm, st, *buf, 
+				 convolution12_s16(buf, afsk26_dem_tables[1][0].i, AFSK26_DEM_SUM_I_1_0),
+				 convolution12_s16(buf, afsk26_dem_tables[1][0].q, AFSK26_DEM_SUM_Q_1_0),
+				 convolution12_s16(buf, afsk26_dem_tables[1][1].i, AFSK26_DEM_SUM_I_1_1),
+				 convolution12_s16(buf, afsk26_dem_tables[1][1].q, AFSK26_DEM_SUM_Q_1_1));
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demod_init_2666(struct sm_state *sm)
+{
+	struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
+
+	st->dcd_time = 400;
+	st->dcd_sum0 = 2;	
+}
+
+/* --------------------------------------------------------------------- */
+
+const struct modem_tx_info sm_afsk2666_tx = {
+	"afsk2666", sizeof(struct mod_state_afsk26), AFSK26_SAMPLERATE, 2666, 
+	modulator_2666_u8, modulator_2666_s16, NULL
+};
+
+const struct modem_rx_info sm_afsk2666_rx = {
+	"afsk2666", sizeof(struct demod_state_afsk26), AFSK26_SAMPLERATE, 2666, 12, 6, 
+	demodulator_2666_u8, demodulator_2666_s16, demod_init_2666
+};
+
+/* --------------------------------------------------------------------- */