patch-2.0.35 linux/drivers/net/soundmodem/sm_afsk2400_7.c

• Lines: 297
• Date: Mon Jul 13 13:47:31 1998
• Orig file: v2.0.34/linux/drivers/net/soundmodem/sm_afsk2400_7.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.0.34/linux/drivers/net/soundmodem/sm_afsk2400_7.c linux/drivers/net/soundmodem/sm_afsk2400_7.c
@@ -0,0 +1,296 @@
+/*****************************************************************************/
+
+/*
+ *	sm_afsk2400_7.c  -- soundcard radio modem driver, 2400 baud AFSK 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 driver is intended to be compatible with TCM3105 modems
+ * overclocked to 7.3728MHz. The mark and space frequencies therefore
+ * lie at 3658 and 1996 Hz.
+ * Note that I do _not_ recommend the building of such links, I provide
+ * this only for the users who live in the coverage area of such
+ * a "legacy" link.
+ */
+
+#include "sm.h"
+#include "sm_tbl_afsk2400_7.h"
+
+/* --------------------------------------------------------------------- */
+
+struct demod_state_afsk24 {
+	unsigned int shreg;
+	unsigned int bit_pll;
+	unsigned char last_sample;
+	unsigned int dcd_shreg;
+	int dcd_sum0, dcd_sum1, dcd_sum2;
+	unsigned int dcd_time;
+	unsigned char last_rxbit;
+};
+
+struct mod_state_afsk24 {
+	unsigned int shreg;
+	unsigned char tx_bit;
+	unsigned int bit_pll;
+	unsigned int tx_seq;
+	unsigned int phinc;
+};
+
+/* --------------------------------------------------------------------- */
+
+static const int dds_inc[2] = { AFSK24_TX_FREQ_LO*0x10000/AFSK24_SAMPLERATE,
+				AFSK24_TX_FREQ_HI*0x10000/AFSK24_SAMPLERATE };
+
+static void modulator_2400_u8(struct sm_state *sm, unsigned char *buf, unsigned int buflen)
+{
+	struct mod_state_afsk24 *st = (struct mod_state_afsk24 *)(&sm->m);
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (st->tx_seq < 0x5555) {
+			if (st->shreg <= 1)
+				st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+			st->tx_bit = (st->tx_bit ^ (!(st->shreg & 1))) & 1;
+			st->shreg >>= 1;
+			st->phinc = dds_inc[st->tx_bit & 1];
+		}
+		st->tx_seq += 0x5555;
+		st->tx_seq &= 0xffff;
+		*buf = OFFSCOS(st->bit_pll);
+		st->bit_pll += st->phinc;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void modulator_2400_s16(struct sm_state *sm, short *buf, unsigned int buflen)
+{
+	struct mod_state_afsk24 *st = (struct mod_state_afsk24 *)(&sm->m);
+
+	for (; buflen > 0; buflen--, buf++) {
+		if (st->tx_seq < 0x5555) {
+			if (st->shreg <= 1)
+				st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
+			st->tx_bit = (st->tx_bit ^ (!(st->shreg & 1))) & 1;
+			st->shreg >>= 1;
+			st->phinc = dds_inc[st->tx_bit & 1];
+		}
+		st->tx_seq += 0x5555;
+		st->tx_seq &= 0xffff;
+		*buf = COS(st->bit_pll);
+		st->bit_pll += st->phinc;
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+extern __inline__ int convolution14_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]);
+	sum += (st[-12] * coeff[12]);
+	sum += (st[-13] * coeff[13]);
+
+	sum >>= 7;
+	return sum * sum;
+}
+
+extern __inline__ int convolution14_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 += (st[-12] * coeff[12]);
+	sum += (st[-13] * coeff[13]);
+
+	sum >>= 15;
+	return sum * sum;
+}
+
+extern __inline__ int do_filter_2400_u8(const unsigned char *buf)
+{
+	int sum = convolution14_u8(buf, afsk24_tx_lo_i, SUM_AFSK24_TX_LO_I);
+	sum += convolution14_u8(buf, afsk24_tx_lo_q, SUM_AFSK24_TX_LO_Q);
+	sum -= convolution14_u8(buf, afsk24_tx_hi_i, SUM_AFSK24_TX_HI_I);
+	sum -= convolution14_u8(buf, afsk24_tx_hi_q, SUM_AFSK24_TX_HI_Q);
+	return sum;
+}
+
+extern __inline__ int do_filter_2400_s16(const short *buf)
+{
+	int sum = convolution14_s16(buf, afsk24_tx_lo_i, SUM_AFSK24_TX_LO_I);
+	sum += convolution14_s16(buf, afsk24_tx_lo_q, SUM_AFSK24_TX_LO_Q);
+	sum -= convolution14_s16(buf, afsk24_tx_hi_i, SUM_AFSK24_TX_HI_I);
+	sum -= convolution14_s16(buf, afsk24_tx_hi_q, SUM_AFSK24_TX_HI_Q);
+	return sum;
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_2400_u8(struct sm_state *sm, const unsigned char *buf, unsigned int buflen)
+{
+	struct demod_state_afsk24 *st = (struct demod_state_afsk24 *)(&sm->d);
+	int j;
+	int sum;
+	unsigned char newsample;
+
+	for (; buflen > 0; buflen--, buf++) {
+		sum = do_filter_2400_u8(buf);
+		st->dcd_shreg <<= 1;
+		st->bit_pll += AFSK24_BITPLL_INC;
+		newsample = (sum > 0);
+		if (st->last_sample ^ newsample) {
+			st->last_sample = newsample;
+			st->dcd_shreg |= 1;
+			if (st->bit_pll < (0x8000+AFSK24_BITPLL_INC/2))
+				st->bit_pll += AFSK24_BITPLL_INC/2;
+			else
+				st->bit_pll -= AFSK24_BITPLL_INC/2;
+			j = /* 2 * */ hweight8(st->dcd_shreg & 0x1c)
+				- hweight16(st->dcd_shreg & 0x1e0);
+			st->dcd_sum0 += j;
+		}
+		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 = 120;
+		}
+		if (st->bit_pll >= 0x10000) {
+			st->bit_pll &= 0xffff;
+			st->shreg >>= 1;
+			st->shreg |= (!(st->last_rxbit ^
+					st->last_sample)) << 16;
+			st->last_rxbit = st->last_sample;
+			diag_trigger(sm);
+			if (st->shreg & 1) {
+				hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
+				st->shreg = 0x10000;
+			}
+		}
+		diag_add(sm, (((int)*buf)-0x80) << 8, sum);
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demodulator_2400_s16(struct sm_state *sm, const short *buf, unsigned int buflen)
+{
+	struct demod_state_afsk24 *st = (struct demod_state_afsk24 *)(&sm->d);
+	int j;
+	int sum;
+	unsigned char newsample;
+
+	for (; buflen > 0; buflen--, buf++) {
+		sum = do_filter_2400_s16(buf);
+		st->dcd_shreg <<= 1;
+		st->bit_pll += AFSK24_BITPLL_INC;
+		newsample = (sum > 0);
+		if (st->last_sample ^ newsample) {
+			st->last_sample = newsample;
+			st->dcd_shreg |= 1;
+			if (st->bit_pll < (0x8000+AFSK24_BITPLL_INC/2))
+				st->bit_pll += AFSK24_BITPLL_INC/2;
+			else
+				st->bit_pll -= AFSK24_BITPLL_INC/2;
+			j = /* 2 * */ hweight8(st->dcd_shreg & 0x1c)
+				- hweight16(st->dcd_shreg & 0x1e0);
+			st->dcd_sum0 += j;
+		}
+		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 = 120;
+		}
+		if (st->bit_pll >= 0x10000) {
+			st->bit_pll &= 0xffff;
+			st->shreg >>= 1;
+			st->shreg |= (!(st->last_rxbit ^
+					st->last_sample)) << 16;
+			st->last_rxbit = st->last_sample;
+			diag_trigger(sm);
+			if (st->shreg & 1) {
+				hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
+				st->shreg = 0x10000;
+			}
+		}
+		diag_add(sm, *buf, sum);
+	}
+}
+
+/* --------------------------------------------------------------------- */
+
+static void demod_init_2400(struct sm_state *sm)
+{
+	struct demod_state_afsk24 *st = (struct demod_state_afsk24 *)(&sm->d);
+
+       	st->dcd_time = 120;
+	st->dcd_sum0 = 2;
+}
+
+/* --------------------------------------------------------------------- */
+
+const struct modem_tx_info sm_afsk2400_7_tx = {
+	"afsk2400_7", sizeof(struct mod_state_afsk24), AFSK24_SAMPLERATE, 2400, 
+	modulator_2400_u8, modulator_2400_s16, NULL
+};
+
+const struct modem_rx_info sm_afsk2400_7_rx = {
+	"afsk2400_7", sizeof(struct demod_state_afsk24), 
+	AFSK24_SAMPLERATE, 2400, 14, AFSK24_SAMPLERATE/2400, 
+	demodulator_2400_u8, demodulator_2400_s16, demod_init_2400
+};
+
+/* --------------------------------------------------------------------- */