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Data Structures | |
struct | filter_struct |
struct | fsk_data |
Defines | |
#define | NCOLA 0x4000 |
#define | PARITY_EVEN 1 |
#define | PARITY_NONE 0 |
#define | PARITY_ODD 2 |
Functions | |
int | fsk_serial (fsk_data *fskd, short *buffer, int *len, int *outbyte) |
int | fskmodem_init (fsk_data *fskd) |
Definition in file fskmodem_int.h.
#define NCOLA 0x4000 |
Definition at line 32 of file fskmodem_int.h.
#define PARITY_EVEN 1 |
Definition at line 28 of file fskmodem_int.h.
#define PARITY_NONE 0 |
Definition at line 27 of file fskmodem_int.h.
#define PARITY_ODD 2 |
Definition at line 29 of file fskmodem_int.h.
int fsk_serial | ( | fsk_data * | fskd, | |
short * | buffer, | |||
int * | len, | |||
int * | outbyte | |||
) |
Definition at line 222 of file fskmodem_float.c.
References idemodulator(), IGET_SAMPLE, fsk_data::ispb, fsk_data::state, STATE_GET_BYTE, STATE_SEARCH_STARTBIT2, STATE_SEARCH_STARTBIT3, fsk_data::xi1, and fsk_data::xi2.
00223 { 00224 int a; 00225 int i,j,n1,r; 00226 int samples = 0; 00227 int olen; 00228 int beginlen=*len; 00229 int beginlenx; 00230 00231 switch (fskd->state) { 00232 /* Pick up where we left off */ 00233 case STATE_SEARCH_STARTBIT2: 00234 goto search_startbit2; 00235 case STATE_SEARCH_STARTBIT3: 00236 goto search_startbit3; 00237 case STATE_GET_BYTE: 00238 goto getbyte; 00239 } 00240 /* We await for start bit */ 00241 do { 00242 /* this was jesus's nice, reasonable, working (at least with RTTY) code 00243 to look for the beginning of the start bit. Unfortunately, since TTY/TDD's 00244 just start sending a start bit with nothing preceding it at the beginning 00245 of a transmission (what a LOSING design), we cant do it this elegantly */ 00246 /* 00247 if (demodulator(zap,&x1)) return(-1); 00248 for (;;) { 00249 if (demodulator(zap,&x2)) return(-1); 00250 if (x1>0 && x2<0) break; 00251 x1 = x2; 00252 } 00253 */ 00254 /* this is now the imprecise, losing, but functional code to detect the 00255 beginning of a start bit in the TDD sceanario. It just looks for sufficient 00256 level to maybe, perhaps, guess, maybe that its maybe the beginning of 00257 a start bit, perhaps. This whole thing stinks! */ 00258 beginlenx=beginlen; /* just to avoid unused war warnings */ 00259 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00260 return -1; 00261 samples++; 00262 for (;;) { 00263 search_startbit2: 00264 if (*len <= 0) { 00265 fskd->state = STATE_SEARCH_STARTBIT2; 00266 return 0; 00267 } 00268 samples++; 00269 if (demodulator(fskd, &fskd->x2, GET_SAMPLE)) 00270 return(-1); 00271 #if 0 00272 printf("x2 = %5.5f ", fskd->x2); 00273 #endif 00274 if (fskd->x2 < -0.5) 00275 break; 00276 } 00277 search_startbit3: 00278 /* We await for 0.5 bits before using DPLL */ 00279 i = fskd->spb/2; 00280 if (*len < i) { 00281 fskd->state = STATE_SEARCH_STARTBIT3; 00282 return 0; 00283 } 00284 for (; i>0; i--) { 00285 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00286 return(-1); 00287 #if 0 00288 printf("x1 = %5.5f ", fskd->x1); 00289 #endif 00290 samples++; 00291 } 00292 00293 /* x1 must be negative (start bit confirmation) */ 00294 00295 } while (fskd->x1 > 0); 00296 fskd->state = STATE_GET_BYTE; 00297 00298 getbyte: 00299 00300 /* Need at least 80 samples (for 1200) or 00301 1320 (for 45.5) to be sure we'll have a byte */ 00302 if (fskd->nbit < 8) { 00303 if (*len < 1320) 00304 return 0; 00305 } else { 00306 if (*len < 80) 00307 return 0; 00308 } 00309 /* Now we read the data bits */ 00310 j = fskd->nbit; 00311 for (a = n1 = 0; j; j--) { 00312 olen = *len; 00313 i = get_bit_raw(fskd, buffer, len); 00314 buffer += (olen - *len); 00315 if (i == -1) 00316 return(-1); 00317 if (i) 00318 n1++; 00319 a >>= 1; 00320 a |= i; 00321 } 00322 j = 8-fskd->nbit; 00323 a >>= j; 00324 00325 /* We read parity bit (if exists) and check parity */ 00326 if (fskd->parity) { 00327 olen = *len; 00328 i = get_bit_raw(fskd, buffer, len); 00329 buffer += (olen - *len); 00330 if (i == -1) 00331 return(-1); 00332 if (i) 00333 n1++; 00334 if (fskd->parity == 1) { /* parity=1 (even) */ 00335 if (n1&1) 00336 a |= 0x100; /* error */ 00337 } else { /* parity=2 (odd) */ 00338 if (!(n1&1)) 00339 a |= 0x100; /* error */ 00340 } 00341 } 00342 00343 /* We read STOP bits. All of them must be 1 */ 00344 00345 for (j = fskd->nstop;j;j--) { 00346 r = get_bit_raw(fskd, buffer, len); 00347 if (r == -1) 00348 return(-1); 00349 if (!r) 00350 a |= 0x200; 00351 } 00352 00353 /* And finally we return */ 00354 /* Bit 8 : Parity error */ 00355 /* Bit 9 : Framming error*/ 00356 00357 *outbyte = a; 00358 fskd->state = STATE_SEARCH_STARTBIT; 00359 return 1; 00360 }
int fskmodem_init | ( | fsk_data * | fskd | ) |
Definition at line 193 of file fskmodem_int.c.
References fsk_data::bw, coef_in, coef_out, fsk_data::demod_filter, fsk_data::f_mark_idx, fsk_data::f_space_idx, filter_struct::icoefs, filter_struct::ip, filter_struct::ixv, filter_struct::iyv, fsk_data::mark_filter, and fsk_data::space_filter.
Referenced by callerid_new(), and tdd_new().
00194 { 00195 int i; 00196 00197 fskd->space_filter.ip = 0; 00198 fskd->mark_filter.ip = 0; 00199 fskd->demod_filter.ip = 0; 00200 00201 for ( i = 0 ; i < 7 ; i++ ) { 00202 fskd->space_filter.icoefs[i] = 00203 coef_in[fskd->f_space_idx][fskd->bw][i] * 256; 00204 fskd->space_filter.ixv[i] = 0;; 00205 fskd->space_filter.iyv[i] = 0;; 00206 00207 fskd->mark_filter.icoefs[i] = 00208 coef_in[fskd->f_mark_idx][fskd->bw][i] * 256; 00209 fskd->mark_filter.ixv[i] = 0;; 00210 fskd->mark_filter.iyv[i] = 0;; 00211 00212 fskd->demod_filter.icoefs[i] = 00213 coef_out[fskd->bw][i] * 1024; 00214 fskd->demod_filter.ixv[i] = 0;; 00215 fskd->demod_filter.iyv[i] = 0;; 00216 } 00217 return 0; 00218 }