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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [drivers/] [net/] [soundmodem/] [sm_afsk2666.c] - Blame information for rev 1765

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Line No. Rev Author Line
1 1626 jcastillo
/*****************************************************************************/
2
 
3
/*
4
 *      sm_afsk2666.c  -- soundcard radio modem driver, 2666 baud AFSK modem
5
 *
6
 *      Copyright (C) 1997  Thomas Sailer (sailer@ife.ee.ethz.ch)
7
 *
8
 *      This program is free software; you can redistribute it and/or modify
9
 *      it under the terms of the GNU General Public License as published by
10
 *      the Free Software Foundation; either version 2 of the License, or
11
 *      (at your option) any later version.
12
 *
13
 *      This program is distributed in the hope that it will be useful,
14
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16
 *      GNU General Public License for more details.
17
 *
18
 *      You should have received a copy of the GNU General Public License
19
 *      along with this program; if not, write to the Free Software
20
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21
 *
22
 *  Please note that the GPL allows you to use the driver, NOT the radio.
23
 *  In order to use the radio, you need a license from the communications
24
 *  authority of your country.
25
 *
26
 */
27
 
28
#include "sm.h"
29
#include "sm_tbl_afsk2666.h"
30
 
31
/* --------------------------------------------------------------------- */
32
 
33
struct demod_state_afsk26 {
34
        unsigned int shreg;
35
        unsigned long descram;
36
        int dem_sum[8];
37
        int dem_sum_mean;
38
        int dem_cnt;
39
        unsigned int bit_pll;
40
        unsigned char last_sample;
41
        unsigned int dcd_shreg;
42
        int dcd_sum0, dcd_sum1, dcd_sum2;
43
        unsigned int dcd_time;
44
};
45
 
46
struct mod_state_afsk26 {
47
        unsigned int shreg;
48
        unsigned long scram;
49
        unsigned int bit_pll;
50
        unsigned int phinc;
51
        unsigned int tx_seq;
52
};
53
 
54
/* --------------------------------------------------------------------- */
55
 
56
#define DESCRAM_TAP1 0x20000
57
#define DESCRAM_TAP2 0x01000
58
#define DESCRAM_TAP3 0x00001
59
 
60
#define DESCRAM_TAPSH1 17
61
#define DESCRAM_TAPSH2 12
62
#define DESCRAM_TAPSH3 0
63
 
64
#define SCRAM_TAP1 0x20000 /* X^17 */
65
#define SCRAM_TAPN 0x00021 /* X^0+X^5 */
66
 
67
/* --------------------------------------------------------------------- */
68
 
69
static void modulator_2666_u8(struct sm_state *sm, unsigned char *buf, unsigned int buflen)
70
{
71
        struct mod_state_afsk26 *st = (struct mod_state_afsk26 *)(&sm->m);
72
 
73
        for (; buflen > 0; buflen--, buf++) {
74
                if (!st->tx_seq++) {
75
                        if (st->shreg <= 1)
76
                                st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
77
                        st->scram = ((st->scram << 1) | (st->scram & 1));
78
                        st->scram ^= (!(st->shreg & 1));
79
                        st->shreg >>= 1;
80
                        if (st->scram & (SCRAM_TAP1 << 1))
81
                                st->scram ^= SCRAM_TAPN << 1;
82
                        st->phinc = afsk26_carfreq[!(st->scram & (SCRAM_TAP1 << 2))];
83
                }
84
                if (st->tx_seq >= 6)
85
                        st->tx_seq = 0;
86
                *buf = OFFSCOS(st->bit_pll);
87
                st->bit_pll += st->phinc;
88
        }
89
}
90
 
91
/* --------------------------------------------------------------------- */
92
 
93
static void modulator_2666_s16(struct sm_state *sm, short *buf, unsigned int buflen)
94
{
95
        struct mod_state_afsk26 *st = (struct mod_state_afsk26 *)(&sm->m);
96
 
97
        for (; buflen > 0; buflen--, buf++) {
98
                if (!st->tx_seq++) {
99
                        if (st->shreg <= 1)
100
                                st->shreg = hdlcdrv_getbits(&sm->hdrv) | 0x10000;
101
                        st->scram = ((st->scram << 1) | (st->scram & 1));
102
                        st->scram ^= (!(st->shreg & 1));
103
                        st->shreg >>= 1;
104
                        if (st->scram & (SCRAM_TAP1 << 1))
105
                                st->scram ^= SCRAM_TAPN << 1;
106
                        st->phinc = afsk26_carfreq[!(st->scram & (SCRAM_TAP1 << 2))];
107
                }
108
                if (st->tx_seq >= 6)
109
                        st->tx_seq = 0;
110
                *buf = COS(st->bit_pll);
111
                st->bit_pll += st->phinc;
112
        }
113
}
114
 
115
/* --------------------------------------------------------------------- */
116
 
117
extern __inline__ int convolution12_u8(const unsigned char *st, const int *coeff, int csum)
118
{
119
        int sum = -0x80 * csum;
120
 
121
        sum += (st[0] * coeff[0]);
122
        sum += (st[-1] * coeff[1]);
123
        sum += (st[-2] * coeff[2]);
124
        sum += (st[-3] * coeff[3]);
125
        sum += (st[-4] * coeff[4]);
126
        sum += (st[-5] * coeff[5]);
127
        sum += (st[-6] * coeff[6]);
128
        sum += (st[-7] * coeff[7]);
129
        sum += (st[-8] * coeff[8]);
130
        sum += (st[-9] * coeff[9]);
131
        sum += (st[-10] * coeff[10]);
132
        sum += (st[-11] * coeff[11]);
133
 
134
        return sum;
135
}
136
 
137
extern __inline__ int convolution12_s16(const short *st, const int *coeff, int csum)
138
{
139
        int sum = 0;
140
 
141
        sum += (st[0] * coeff[0]);
142
        sum += (st[-1] * coeff[1]);
143
        sum += (st[-2] * coeff[2]);
144
        sum += (st[-3] * coeff[3]);
145
        sum += (st[-4] * coeff[4]);
146
        sum += (st[-5] * coeff[5]);
147
        sum += (st[-6] * coeff[6]);
148
        sum += (st[-7] * coeff[7]);
149
        sum += (st[-8] * coeff[8]);
150
        sum += (st[-9] * coeff[9]);
151
        sum += (st[-10] * coeff[10]);
152
        sum += (st[-11] * coeff[11]);
153
 
154
        sum >>= 8;
155
        return sum;
156
}
157
 
158
/* ---------------------------------------------------------------------- */
159
 
160
#if 0
161
static int binexp(unsigned int i)
162
{
163
        int ret = 31;
164
 
165
        if (!i)
166
                return 0;
167
        if (i < 0x10000LU) {
168
                i <<= 16;
169
                ret -= 16;
170
        }
171
        if (i < 0x1000000LU) {
172
                i <<= 8;
173
                ret -= 8;
174
        }
175
        if (i < 0x10000000LU) {
176
                i <<= 4;
177
                ret -= 4;
178
        }
179
        if (i < 0x40000000LU) {
180
                i <<= 2;
181
                ret -= 2;
182
        }
183
        if (i < 0x80000000LU)
184
                ret -= 1;
185
        return ret;
186
}
187
 
188
static const sqrt_tab[16] = {
189
        00000, 16384, 23170, 28378, 32768, 36636, 40132, 43348,
190
        46341, 49152, 51811, 54340, 56756, 59073, 61303, 63455
191
};
192
 
193
 
194
static unsigned int int_sqrt_approx(unsigned int i)
195
{
196
        unsigned int j;
197
 
198
        if (i < 16)
199
                return sqrt_tab[i] >> 14;
200
        j = binexp(i) >> 1;
201
        i >>= (j * 2 - 2);
202
        return (sqrt_tab[i & 0xf] << j) >> 15;
203
}
204
#endif
205
 
206
/* --------------------------------------------------------------------- */
207
 
208
extern unsigned int est_pwr(int i, int q)
209
{
210
        unsigned int ui = abs(i);
211
        unsigned int uq = abs(q);
212
 
213
        if (uq > ui) {
214
                unsigned int tmp;
215
                tmp = ui;
216
                ui = uq;
217
                uq = tmp;
218
        }
219
        if (uq > (ui >> 1))
220
                return 7*(ui>>3) + 9*(uq>>4);
221
        else
222
                return ui + (uq>>2);
223
}
224
 
225
/* --------------------------------------------------------------------- */
226
 
227
static void demod_one_sample(struct sm_state *sm, struct demod_state_afsk26 *st, int curval,
228
                             int loi, int loq, int hii, int hiq)
229
{
230
        static const int pll_corr[2] = { -0xa00, 0xa00 };
231
        unsigned char curbit;
232
        unsigned int descx;
233
        int val;
234
 
235
        /*
236
         * estimate power
237
         */
238
        val = est_pwr(hii, hiq) - est_pwr(loi, loq);
239
        /*
240
         * estimate center value
241
         */
242
        st->dem_sum[0] += val >> 8;
243
        if ((++st->dem_cnt) >= 256) {
244
                st->dem_cnt = 0;
245
                st->dem_sum_mean = (st->dem_sum[0]+st->dem_sum[1]+
246
                                    st->dem_sum[2]+st->dem_sum[3]+
247
                                    st->dem_sum[4]+st->dem_sum[5]+
248
                                    st->dem_sum[6]+st->dem_sum[7]) >> 3;
249
                memmove(st->dem_sum+1, st->dem_sum,
250
                        sizeof(st->dem_sum)-sizeof(st->dem_sum[0]));
251
                st->dem_sum[0] = 0;
252
        }
253
        /*
254
         * decision and bit clock regen
255
         */
256
        val -= st->dem_sum_mean;
257
        diag_add(sm, curval, val);
258
 
259
        st->dcd_shreg <<= 1;
260
        st->bit_pll += 0x1555;
261
        curbit = (val > 0);
262
        if (st->last_sample ^ curbit) {
263
                st->dcd_shreg |= 1;
264
                st->bit_pll += pll_corr[st->bit_pll < (0x8000+0x1555)];
265
                st->dcd_sum0 += 4*hweight8(st->dcd_shreg & 0x1e) -
266
                        hweight16(st->dcd_shreg & 0xfe00);
267
        }
268
        st->last_sample = curbit;
269
        hdlcdrv_channelbit(&sm->hdrv, curbit);
270
        if ((--st->dcd_time) <= 0) {
271
                hdlcdrv_setdcd(&sm->hdrv, (st->dcd_sum0 + st->dcd_sum1 +
272
                                           st->dcd_sum2) < 0);
273
                st->dcd_sum2 = st->dcd_sum1;
274
                st->dcd_sum1 = st->dcd_sum0;
275
                st->dcd_sum0 = 2; /* slight bias */
276
                st->dcd_time = 400;
277
        }
278
        if (st->bit_pll >= 0x10000) {
279
                st->bit_pll &= 0xffffu;
280
                st->descram = (st->descram << 1) | curbit;
281
                descx = st->descram ^ (st->descram >> 1);
282
                descx ^= ((descx >> DESCRAM_TAPSH1) ^
283
                          (descx >> DESCRAM_TAPSH2));
284
                st->shreg >>= 1;
285
                st->shreg |= (!(descx & 1)) << 16;
286
                if (st->shreg & 1) {
287
                        hdlcdrv_putbits(&sm->hdrv, st->shreg >> 1);
288
                        st->shreg = 0x10000;
289
                }
290
                diag_trigger(sm);
291
        }
292
}
293
 
294
/* --------------------------------------------------------------------- */
295
 
296
static void demodulator_2666_u8(struct sm_state *sm, const unsigned char *buf, unsigned int buflen)
297
{
298
        struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
299
 
300
        for (; buflen > 0; buflen--, buf++) {
301
                demod_one_sample(sm, st, (*buf-0x80)<<8,
302
                                 convolution12_u8(buf, afsk26_dem_tables[0][0].i, AFSK26_DEM_SUM_I_0_0),
303
                                 convolution12_u8(buf, afsk26_dem_tables[0][0].q, AFSK26_DEM_SUM_Q_0_0),
304
                                 convolution12_u8(buf, afsk26_dem_tables[0][1].i, AFSK26_DEM_SUM_I_0_1),
305
                                 convolution12_u8(buf, afsk26_dem_tables[0][1].q, AFSK26_DEM_SUM_Q_0_1));
306
                demod_one_sample(sm, st,  (*buf-0x80)<<8,
307
                                 convolution12_u8(buf, afsk26_dem_tables[1][0].i, AFSK26_DEM_SUM_I_1_0),
308
                                 convolution12_u8(buf, afsk26_dem_tables[1][0].q, AFSK26_DEM_SUM_Q_1_0),
309
                                 convolution12_u8(buf, afsk26_dem_tables[1][1].i, AFSK26_DEM_SUM_I_1_1),
310
                                 convolution12_u8(buf, afsk26_dem_tables[1][1].q, AFSK26_DEM_SUM_Q_1_1));
311
        }
312
}
313
 
314
/* --------------------------------------------------------------------- */
315
 
316
static void demodulator_2666_s16(struct sm_state *sm, const short *buf, unsigned int buflen)
317
{
318
        struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
319
 
320
        for (; buflen > 0; buflen--, buf++) {
321
                demod_one_sample(sm, st, *buf,
322
                                 convolution12_s16(buf, afsk26_dem_tables[0][0].i, AFSK26_DEM_SUM_I_0_0),
323
                                 convolution12_s16(buf, afsk26_dem_tables[0][0].q, AFSK26_DEM_SUM_Q_0_0),
324
                                 convolution12_s16(buf, afsk26_dem_tables[0][1].i, AFSK26_DEM_SUM_I_0_1),
325
                                 convolution12_s16(buf, afsk26_dem_tables[0][1].q, AFSK26_DEM_SUM_Q_0_1));
326
                demod_one_sample(sm, st, *buf,
327
                                 convolution12_s16(buf, afsk26_dem_tables[1][0].i, AFSK26_DEM_SUM_I_1_0),
328
                                 convolution12_s16(buf, afsk26_dem_tables[1][0].q, AFSK26_DEM_SUM_Q_1_0),
329
                                 convolution12_s16(buf, afsk26_dem_tables[1][1].i, AFSK26_DEM_SUM_I_1_1),
330
                                 convolution12_s16(buf, afsk26_dem_tables[1][1].q, AFSK26_DEM_SUM_Q_1_1));
331
        }
332
}
333
 
334
/* --------------------------------------------------------------------- */
335
 
336
static void demod_init_2666(struct sm_state *sm)
337
{
338
        struct demod_state_afsk26 *st = (struct demod_state_afsk26 *)(&sm->d);
339
 
340
        st->dcd_time = 400;
341
        st->dcd_sum0 = 2;
342
}
343
 
344
/* --------------------------------------------------------------------- */
345
 
346
const struct modem_tx_info sm_afsk2666_tx = {
347
        "afsk2666", sizeof(struct mod_state_afsk26), AFSK26_SAMPLERATE, 2666,
348
        modulator_2666_u8, modulator_2666_s16, NULL
349
};
350
 
351
const struct modem_rx_info sm_afsk2666_rx = {
352
        "afsk2666", sizeof(struct demod_state_afsk26), AFSK26_SAMPLERATE, 2666, 12, 6,
353
        demodulator_2666_u8, demodulator_2666_s16, demod_init_2666
354
};
355
 
356
/* --------------------------------------------------------------------- */

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