FSK Modem Support. More...
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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) |
FSK Modem Support.
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 226 of file fskmodem_float.c.
References demodulator(), get_bit_raw(), GET_SAMPLE, idemodulator(), IGET_SAMPLE, fsk_data::instop, fsk_data::ispb, fsk_data::nbit, fsk_data::nstop, fsk_data::parity, ast_frame::samples, fsk_data::spb, fsk_data::state, STATE_GET_BYTE, STATE_SEARCH_STARTBIT, STATE_SEARCH_STARTBIT2, STATE_SEARCH_STARTBIT3, fsk_data::x1, fsk_data::x2, fsk_data::xi1, and fsk_data::xi2.
00227 { 00228 int a; 00229 int i,j,n1,r; 00230 int samples = 0; 00231 int olen; 00232 00233 switch (fskd->state) { 00234 /* Pick up where we left off */ 00235 case STATE_SEARCH_STARTBIT2: 00236 goto search_startbit2; 00237 case STATE_SEARCH_STARTBIT3: 00238 goto search_startbit3; 00239 case STATE_GET_BYTE: 00240 goto getbyte; 00241 } 00242 /* We await for start bit */ 00243 do { 00244 /* this was jesus's nice, reasonable, working (at least with RTTY) code 00245 to look for the beginning of the start bit. Unfortunately, since TTY/TDD's 00246 just start sending a start bit with nothing preceding it at the beginning 00247 of a transmission (what a LOSING design), we cant do it this elegantly */ 00248 /* 00249 if (demodulator(zap,&x1)) return(-1); 00250 for (;;) { 00251 if (demodulator(zap,&x2)) return(-1); 00252 if (x1>0 && x2<0) break; 00253 x1 = x2; 00254 } 00255 */ 00256 /* this is now the imprecise, losing, but functional code to detect the 00257 beginning of a start bit in the TDD sceanario. It just looks for sufficient 00258 level to maybe, perhaps, guess, maybe that its maybe the beginning of 00259 a start bit, perhaps. This whole thing stinks! */ 00260 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00261 return -1; 00262 samples++; 00263 for (;;) { 00264 search_startbit2: 00265 if (*len <= 0) { 00266 fskd->state = STATE_SEARCH_STARTBIT2; 00267 return 0; 00268 } 00269 samples++; 00270 if (demodulator(fskd, &fskd->x2, GET_SAMPLE)) 00271 return(-1); 00272 #if 0 00273 printf("x2 = %5.5f ", fskd->x2); 00274 #endif 00275 if (fskd->x2 < -0.5) 00276 break; 00277 } 00278 search_startbit3: 00279 /* We await for 0.5 bits before using DPLL */ 00280 i = fskd->spb/2; 00281 if (*len < i) { 00282 fskd->state = STATE_SEARCH_STARTBIT3; 00283 return 0; 00284 } 00285 for (; i>0; i--) { 00286 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00287 return(-1); 00288 #if 0 00289 printf("x1 = %5.5f ", fskd->x1); 00290 #endif 00291 samples++; 00292 } 00293 00294 /* x1 must be negative (start bit confirmation) */ 00295 00296 } while (fskd->x1 > 0); 00297 fskd->state = STATE_GET_BYTE; 00298 00299 getbyte: 00300 00301 /* Need at least 80 samples (for 1200) or 00302 1320 (for 45.5) to be sure we'll have a byte */ 00303 if (fskd->nbit < 8) { 00304 if (*len < 1320) 00305 return 0; 00306 } else { 00307 if (*len < 80) 00308 return 0; 00309 } 00310 /* Now we read the data bits */ 00311 j = fskd->nbit; 00312 for (a = n1 = 0; j; j--) { 00313 olen = *len; 00314 i = get_bit_raw(fskd, buffer, len); 00315 buffer += (olen - *len); 00316 if (i == -1) 00317 return(-1); 00318 if (i) 00319 n1++; 00320 a >>= 1; 00321 a |= i; 00322 } 00323 j = 8-fskd->nbit; 00324 a >>= j; 00325 00326 /* We read parity bit (if exists) and check parity */ 00327 if (fskd->parity) { 00328 olen = *len; 00329 i = get_bit_raw(fskd, buffer, len); 00330 buffer += (olen - *len); 00331 if (i == -1) 00332 return(-1); 00333 if (i) 00334 n1++; 00335 if (fskd->parity == 1) { /* parity=1 (even) */ 00336 if (n1&1) 00337 a |= 0x100; /* error */ 00338 } else { /* parity=2 (odd) */ 00339 if (!(n1&1)) 00340 a |= 0x100; /* error */ 00341 } 00342 } 00343 00344 /* We read STOP bits. All of them must be 1 */ 00345 00346 for (j = fskd->nstop;j;j--) { 00347 r = get_bit_raw(fskd, buffer, len); 00348 if (r == -1) 00349 return(-1); 00350 if (!r) 00351 a |= 0x200; 00352 } 00353 00354 /* And finally we return */ 00355 /* Bit 8 : Parity error */ 00356 /* Bit 9 : Framming error*/ 00357 00358 *outbyte = a; 00359 fskd->state = STATE_SEARCH_STARTBIT; 00360 return 1; 00361 }
int fskmodem_init | ( | fsk_data * | fskd | ) |
Definition at line 197 of file fskmodem_int.c.
References fsk_data::bw, 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().
00198 { 00199 int i; 00200 00201 fskd->space_filter.ip = 0; 00202 fskd->mark_filter.ip = 0; 00203 fskd->demod_filter.ip = 0; 00204 00205 for ( i = 0 ; i < 7 ; i++ ) { 00206 fskd->space_filter.icoefs[i] = 00207 coef_in[fskd->f_space_idx][fskd->bw][i] * 256; 00208 fskd->space_filter.ixv[i] = 0;; 00209 fskd->space_filter.iyv[i] = 0;; 00210 00211 fskd->mark_filter.icoefs[i] = 00212 coef_in[fskd->f_mark_idx][fskd->bw][i] * 256; 00213 fskd->mark_filter.ixv[i] = 0;; 00214 fskd->mark_filter.iyv[i] = 0;; 00215 00216 fskd->demod_filter.icoefs[i] = 00217 coef_out[fskd->bw][i] * 1024; 00218 fskd->demod_filter.ixv[i] = 0;; 00219 fskd->demod_filter.iyv[i] = 0;; 00220 } 00221 return 0; 00222 }