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[/] [or1k/] [tags/] [before_ORP/] [uclinux/] [uClinux-2.0.x/] [drivers/] [net/] [soundmodem/] [sm_afsk2666.c] - Rev 901
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/*****************************************************************************/ /* * 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 }; /* --------------------------------------------------------------------- */
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