#include "asterisk.h"
#include <stdio.h>
#include "asterisk/fskmodem.h"
Go to the source code of this file.
Defines | |
#define | BWLIST {75,800} |
#define | FLIST {1400,1800,1200,2200,1300,2100} |
#define | GET_SAMPLE get_sample(&buffer, len) |
#define | NBW 2 |
#define | NF 6 |
#define | STATE_GET_BYTE 3 |
#define | STATE_SEARCH_STARTBIT 0 |
#define | STATE_SEARCH_STARTBIT2 1 |
#define | STATE_SEARCH_STARTBIT3 2 |
Functions | |
static int | demodulator (fsk_data *fskd, float *retval, float x) |
static float | filterL (fsk_data *fskd, float in) |
static float | filterM (fsk_data *fskd, float in) |
static float | filterS (fsk_data *fskd, float in) |
int | fsk_serial (fsk_data *fskd, short *buffer, int *len, int *outbyte) |
static int | get_bit_raw (fsk_data *fskd, short *buffer, int *len) |
static float | get_sample (short **buffer, int *len) |
Variables | |
static double | coef_in [NF][NBW][8] |
Coefficients for input filters Coefficients table, generated by program "mkfilter" mkfilter is part of the zapatatelephony.org distribution Format: coef[IDX_FREC][IDX_BW][IDX_COEF] IDX_COEF = 0 => 1/GAIN IDX_COEF = 1-6 => Coefficientes y[n]. | |
static double | coef_out [NBW][8] |
Coefficients for output filter Coefficients table, generated by program "mkfilter" Format: coef[IDX_BW][IDX_COEF] IDX_COEF = 0 => 1/GAIN IDX_COEF = 1-6 => Coefficientes y[n]. |
Definition in file fskmodem_float.c.
#define BWLIST {75,800} |
Definition at line 40 of file fskmodem_float.c.
#define FLIST {1400,1800,1200,2200,1300,2100} |
Definition at line 42 of file fskmodem_float.c.
#define GET_SAMPLE get_sample(&buffer, len) |
#define NBW 2 |
Definition at line 39 of file fskmodem_float.c.
#define NF 6 |
Definition at line 41 of file fskmodem_float.c.
#define STATE_GET_BYTE 3 |
#define STATE_SEARCH_STARTBIT 0 |
Definition at line 44 of file fskmodem_float.c.
#define STATE_SEARCH_STARTBIT2 1 |
#define STATE_SEARCH_STARTBIT3 2 |
static int demodulator | ( | fsk_data * | fskd, | |
float * | retval, | |||
float | x | |||
) | [inline, static] |
Definition at line 167 of file fskmodem_float.c.
References fsk_data::cola_demod, fsk_data::cola_filter, fsk_data::cola_in, filterL(), filterM(), filterS(), NCOLA, and fsk_data::pcola.
Referenced by fsk_serial(), and get_bit_raw().
00168 { 00169 float xS,xM; 00170 00171 fskd->cola_in[fskd->pcola] = x; 00172 00173 xS = filterS(fskd,x); 00174 xM = filterM(fskd,x); 00175 00176 fskd->cola_filter[fskd->pcola] = xM-xS; 00177 00178 x = filterL(fskd,xM*xM - xS*xS); 00179 00180 fskd->cola_demod[fskd->pcola++] = x; 00181 fskd->pcola &= (NCOLA-1); 00182 00183 *retval = x; 00184 return 0; 00185 }
static float filterL | ( | fsk_data * | fskd, | |
float | in | |||
) | [inline, static] |
Low-pass filter for demodulated data
Definition at line 145 of file fskmodem_float.c.
References fsk_data::bw, fsk_data::flp, fsk_data::flxv, and fsk_data::flyv.
Referenced by demodulator().
00146 { 00147 int i, j; 00148 double s; 00149 double *pc; 00150 00151 pc = &coef_out[fskd->bw][0]; 00152 fskd->flxv[(fskd->flp + 6) & 7] = in * (*pc++); 00153 00154 s = (fskd->flxv[fskd->flp] + fskd->flxv[(fskd->flp+6)&7]) + 00155 6 * (fskd->flxv[(fskd->flp+1)&7] + fskd->flxv[(fskd->flp+5)&7]) + 00156 15 * (fskd->flxv[(fskd->flp+2)&7] + fskd->flxv[(fskd->flp+4)&7]) + 00157 20 * fskd->flxv[(fskd->flp+3)&7]; 00158 00159 for (i = 0,j = fskd->flp;i<6;i++,j++) 00160 s += fskd->flyv[j&7]*(*pc++); 00161 fskd->flyv[j&7] = s; 00162 fskd->flp++; 00163 fskd->flp &= 7; 00164 return s; 00165 }
static float filterM | ( | fsk_data * | fskd, | |
float | in | |||
) | [inline, static] |
Band-pass filter for MARK frequency
Definition at line 107 of file fskmodem_float.c.
References fsk_data::bw, fsk_data::f_mark_idx, fsk_data::fmp, fsk_data::fmxv, and fsk_data::fmyv.
Referenced by demodulator().
00108 { 00109 int i, j; 00110 double s; 00111 double *pc; 00112 00113 pc = &coef_in[fskd->f_mark_idx][fskd->bw][0]; 00114 fskd->fmxv[(fskd->fmp+6)&7] = in*(*pc++); 00115 00116 s = (fskd->fmxv[(fskd->fmp + 6) & 7] - fskd->fmxv[fskd->fmp]) + 3 * (fskd->fmxv[(fskd->fmp + 2) & 7] - fskd->fmxv[(fskd->fmp + 4) & 7]); 00117 for (i = 0, j = fskd->fmp; i < 6; i++, j++) 00118 s += fskd->fmyv[j&7]*(*pc++); 00119 fskd->fmyv[j&7] = s; 00120 fskd->fmp++; 00121 fskd->fmp &= 7; 00122 return s; 00123 }
static float filterS | ( | fsk_data * | fskd, | |
float | in | |||
) | [inline, static] |
Band-pass filter for SPACE frequency
Definition at line 126 of file fskmodem_float.c.
References fsk_data::bw, fsk_data::f_space_idx, fsk_data::fsp, fsk_data::fsxv, and fsk_data::fsyv.
Referenced by demodulator().
00127 { 00128 int i, j; 00129 double s; 00130 double *pc; 00131 00132 pc = &coef_in[fskd->f_space_idx][fskd->bw][0]; 00133 fskd->fsxv[(fskd->fsp+6)&7] = in*(*pc++); 00134 00135 s = (fskd->fsxv[(fskd->fsp + 6) & 7] - fskd->fsxv[fskd->fsp]) + 3 * (fskd->fsxv[(fskd->fsp + 2) & 7] - fskd->fsxv[(fskd->fsp + 4) & 7]); 00136 for (i = 0, j = fskd->fsp; i < 6; i++, j++) 00137 s += fskd->fsyv[j&7]*(*pc++); 00138 fskd->fsyv[j&7] = s; 00139 fskd->fsp++; 00140 fskd->fsp &= 7; 00141 return s; 00142 }
int fsk_serial | ( | fsk_data * | fskd, | |
short * | buffer, | |||
int * | len, | |||
int * | outbyte | |||
) |
Definition at line 222 of file fskmodem_float.c.
References demodulator(), GET_SAMPLE, fsk_data::nbit, ast_frame::samples, fsk_data::spb, fsk_data::state, STATE_GET_BYTE, STATE_SEARCH_STARTBIT2, STATE_SEARCH_STARTBIT3, fsk_data::x1, and fsk_data::x2.
00223 { 00224 int a; 00225 int i,j,n1,r; 00226 int samples = 0; 00227 int olen; 00228 00229 switch (fskd->state) { 00230 /* Pick up where we left off */ 00231 case STATE_SEARCH_STARTBIT2: 00232 goto search_startbit2; 00233 case STATE_SEARCH_STARTBIT3: 00234 goto search_startbit3; 00235 case STATE_GET_BYTE: 00236 goto getbyte; 00237 } 00238 /* We await for start bit */ 00239 do { 00240 /* this was jesus's nice, reasonable, working (at least with RTTY) code 00241 to look for the beginning of the start bit. Unfortunately, since TTY/TDD's 00242 just start sending a start bit with nothing preceding it at the beginning 00243 of a transmission (what a LOSING design), we cant do it this elegantly */ 00244 /* 00245 if (demodulator(zap,&x1)) return(-1); 00246 for (;;) { 00247 if (demodulator(zap,&x2)) return(-1); 00248 if (x1>0 && x2<0) break; 00249 x1 = x2; 00250 } 00251 */ 00252 /* this is now the imprecise, losing, but functional code to detect the 00253 beginning of a start bit in the TDD sceanario. It just looks for sufficient 00254 level to maybe, perhaps, guess, maybe that its maybe the beginning of 00255 a start bit, perhaps. This whole thing stinks! */ 00256 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00257 return -1; 00258 samples++; 00259 for (;;) { 00260 search_startbit2: 00261 if (*len <= 0) { 00262 fskd->state = STATE_SEARCH_STARTBIT2; 00263 return 0; 00264 } 00265 samples++; 00266 if (demodulator(fskd, &fskd->x2, GET_SAMPLE)) 00267 return(-1); 00268 #if 0 00269 printf("x2 = %5.5f ", fskd->x2); 00270 #endif 00271 if (fskd->x2 < -0.5) 00272 break; 00273 } 00274 search_startbit3: 00275 /* We await for 0.5 bits before using DPLL */ 00276 i = fskd->spb/2; 00277 if (*len < i) { 00278 fskd->state = STATE_SEARCH_STARTBIT3; 00279 return 0; 00280 } 00281 for (; i>0; i--) { 00282 if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) 00283 return(-1); 00284 #if 0 00285 printf("x1 = %5.5f ", fskd->x1); 00286 #endif 00287 samples++; 00288 } 00289 00290 /* x1 must be negative (start bit confirmation) */ 00291 00292 } while (fskd->x1 > 0); 00293 fskd->state = STATE_GET_BYTE; 00294 00295 getbyte: 00296 00297 /* Need at least 80 samples (for 1200) or 00298 1320 (for 45.5) to be sure we'll have a byte */ 00299 if (fskd->nbit < 8) { 00300 if (*len < 1320) 00301 return 0; 00302 } else { 00303 if (*len < 80) 00304 return 0; 00305 } 00306 /* Now we read the data bits */ 00307 j = fskd->nbit; 00308 for (a = n1 = 0; j; j--) { 00309 olen = *len; 00310 i = get_bit_raw(fskd, buffer, len); 00311 buffer += (olen - *len); 00312 if (i == -1) 00313 return(-1); 00314 if (i) 00315 n1++; 00316 a >>= 1; 00317 a |= i; 00318 } 00319 j = 8-fskd->nbit; 00320 a >>= j; 00321 00322 /* We read parity bit (if exists) and check parity */ 00323 if (fskd->parity) { 00324 olen = *len; 00325 i = get_bit_raw(fskd, buffer, len); 00326 buffer += (olen - *len); 00327 if (i == -1) 00328 return(-1); 00329 if (i) 00330 n1++; 00331 if (fskd->parity == 1) { /* parity=1 (even) */ 00332 if (n1&1) 00333 a |= 0x100; /* error */ 00334 } else { /* parity=2 (odd) */ 00335 if (!(n1&1)) 00336 a |= 0x100; /* error */ 00337 } 00338 } 00339 00340 /* We read STOP bits. All of them must be 1 */ 00341 00342 for (j = fskd->nstop;j;j--) { 00343 r = get_bit_raw(fskd, buffer, len); 00344 if (r == -1) 00345 return(-1); 00346 if (!r) 00347 a |= 0x200; 00348 } 00349 00350 /* And finally we return */ 00351 /* Bit 8 : Parity error */ 00352 /* Bit 9 : Framming error*/ 00353 00354 *outbyte = a; 00355 fskd->state = STATE_SEARCH_STARTBIT; 00356 return 1; 00357 }
static int get_bit_raw | ( | fsk_data * | fskd, | |
short * | buffer, | |||
int * | len | |||
) | [static] |
Definition at line 187 of file fskmodem_float.c.
References fsk_data::cont, demodulator(), f, GET_SAMPLE, fsk_data::spb, and fsk_data::x0.
00188 { 00189 /* This function implements a DPLL to synchronize with the bits */ 00190 float x,spb,spb2,ds; 00191 int f; 00192 00193 spb = fskd->spb; 00194 if (fskd->spb == 7) 00195 spb = 8000.0 / 1200.0; 00196 ds = spb/32.; 00197 spb2 = spb/2.; 00198 00199 for (f = 0;;) { 00200 if (demodulator(fskd, &x, GET_SAMPLE)) 00201 return -1; 00202 if ((x * fskd->x0) < 0) { /* Transition */ 00203 if (!f) { 00204 if (fskd->cont<(spb2)) 00205 fskd->cont += ds; 00206 else 00207 fskd->cont -= ds; 00208 f = 1; 00209 } 00210 } 00211 fskd->x0 = x; 00212 fskd->cont += 1.; 00213 if (fskd->cont > spb) { 00214 fskd->cont -= spb; 00215 break; 00216 } 00217 } 00218 f = (x > 0) ? 0x80 : 0; 00219 return f; 00220 }
static float get_sample | ( | short ** | buffer, | |
int * | len | |||
) | [inline, static] |
Definition at line 49 of file fskmodem_float.c.
00050 { 00051 float retval; 00052 retval = (float) **buffer / 256; 00053 (*buffer)++; 00054 (*len)--; 00055 return retval; 00056 };
double coef_in[NF][NBW][8] [static] |
Coefficients for input filters Coefficients table, generated by program "mkfilter" mkfilter is part of the zapatatelephony.org distribution Format: coef[IDX_FREC][IDX_BW][IDX_COEF] IDX_COEF = 0 => 1/GAIN IDX_COEF = 1-6 => Coefficientes y[n].
Definition at line 67 of file fskmodem_float.c.
Referenced by fskmodem_init().
double coef_out[NBW][8] [static] |
Initial value:
{ { 1.3868644653e-08,-6.3283665042e-01,4.0895057217e+00,-1.1020074592e+01,1.5850766191e+01,-1.2835109292e+01,5.5477477340e+00,0.0000000000e+00, }, { 3.1262119724e-03,-7.8390522307e-03,8.5209627801e-02,-4.0804129163e-01,1.1157139955e+00,-1.8767603680e+00,1.8916395224e+00,0.0000000000e+00, }, }
Definition at line 100 of file fskmodem_float.c.
Referenced by fskmodem_init().