From 270a084091952b3d63d198e334cfaca8f947fe55 Mon Sep 17 00:00:00 2001 From: tilghman Date: Mon, 21 Jul 2008 21:02:25 +0000 Subject: Merged revisions 132510 via svnmerge from https://origsvn.digium.com/svn/asterisk/trunk ........ r132510 | tilghman | 2008-07-21 15:59:03 -0500 (Mon, 21 Jul 2008) | 5 lines Optionally build integer-based routines for FSK tone decoding (but default to the more accurate float-based routines). (Closes issue #11679) (Step 1 of 2) ........ git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.0@132512 f38db490-d61c-443f-a65b-d21fe96a405b --- main/fskmodem_float.c | 360 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 360 insertions(+) create mode 100644 main/fskmodem_float.c (limited to 'main/fskmodem_float.c') diff --git a/main/fskmodem_float.c b/main/fskmodem_float.c new file mode 100644 index 000000000..f77300979 --- /dev/null +++ b/main/fskmodem_float.c @@ -0,0 +1,360 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 1999 - 2005, Digium, Inc. + * + * Mark Spencer + * + * Includes code and algorithms from the Zapata library. + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ + +/*! \file + * + * \brief FSK Modulator/Demodulator + * + * \author Mark Spencer + * + * \arg Includes code and algorithms from the Zapata library. + * + */ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#include + +#include "asterisk/fskmodem.h" + +#define NBW 2 +#define BWLIST {75,800} +#define NF 6 +#define FLIST {1400,1800,1200,2200,1300,2100} + +#define STATE_SEARCH_STARTBIT 0 +#define STATE_SEARCH_STARTBIT2 1 +#define STATE_SEARCH_STARTBIT3 2 +#define STATE_GET_BYTE 3 + +static inline float get_sample(short **buffer, int *len) +{ + float retval; + retval = (float) **buffer / 256; + (*buffer)++; + (*len)--; + return retval; +}; + +#define GET_SAMPLE get_sample(&buffer, len) + +/*! \brief 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_in[NF][NBW][8] = { + { + { 1.8229206611e-04,-7.8997325866e-01,2.2401819940e+00,-4.6751353581e+00,5.5080745712e+00,-5.0571565772e+00,2.6215820004e+00,0.0000000000e+00, }, + { 9.8532175289e-02,-5.6297236492e-02,3.3146713415e-01,-9.2239200436e-01,1.4844365184e+00,-2.0183258642e+00,2.0074154497e+00,0.0000000000e+00, }, + }, + { + { 1.8229206610e-04,-7.8997325866e-01,7.7191410839e-01,-2.8075643964e+00,1.6948618347e+00,-3.0367273700e+00,9.0333559408e-01,0.0000000000e+00, } , + { 9.8531161839e-02,-5.6297236492e-02,1.1421579050e-01,-4.8122536483e-01,4.0121072432e-01,-7.4834487567e-01,6.9170822332e-01,0.0000000000e+00, }, + }, + { + { 1.8229206611e-04,-7.8997325866e-01,2.9003821430e+00,-6.1082779024e+00,7.7169345751e+00,-6.6075999680e+00,3.3941838836e+00,0.0000000000e+00, }, + { 9.8539686961e-02,-5.6297236492e-02,4.2915323820e-01,-1.2609358633e+00,2.2399213250e+00,-2.9928879142e+00,2.5990173742e+00,0.0000000000e+00, }, + }, + { + { 1.8229206610e-04,-7.8997325866e-01,-7.7191410839e-01,-2.8075643964e+00,-1.6948618347e+00,-3.0367273700e+00,-9.0333559408e-01,0.0000000000e+00, }, + { 9.8531161839e-02,-5.6297236492e-02,-1.1421579050e-01,-4.8122536483e-01,-4.0121072432e-01,-7.4834487567e-01,-6.9170822332e-01,0.0000000000e+00, }, + }, + { + { 1.8229206611e-04,-7.8997325866e-01,2.5782298908e+00,-5.3629717478e+00,6.5890882172e+00,-5.8012914776e+00,3.0171839130e+00,0.0000000000e+00, }, + { 9.8534230718e-02,-5.6297236492e-02,3.8148618075e-01,-1.0848760410e+00,1.8441165168e+00,-2.4860666655e+00,2.3103384142e+00,0.0000000000e+00, }, + }, + { + { 1.8229206610e-04,-7.8997325866e-01,-3.8715051001e-01,-2.6192408538e+00,-8.3977994034e-01,-2.8329897913e+00,-4.5306444352e-01,0.0000000000e+00, }, + { 9.8531160936e-02,-5.6297236492e-02,-5.7284484199e-02,-4.3673866734e-01,-1.9564766257e-01,-6.2028156584e-01,-3.4692356122e-01,0.0000000000e+00, }, + }, +}; + +/*! \brief 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] + */ +static double coef_out[NBW][8] = { + { 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, }, +}; + + +/*! Band-pass filter for MARK frequency */ +static inline float filterM(fsk_data *fskd,float in) +{ + int i, j; + double s; + double *pc; + + pc = &coef_in[fskd->f_mark_idx][fskd->bw][0]; + fskd->fmxv[(fskd->fmp+6)&7] = in*(*pc++); + + s = (fskd->fmxv[(fskd->fmp + 6) & 7] - fskd->fmxv[fskd->fmp]) + 3 * (fskd->fmxv[(fskd->fmp + 2) & 7] - fskd->fmxv[(fskd->fmp + 4) & 7]); + for (i = 0, j = fskd->fmp; i < 6; i++, j++) + s += fskd->fmyv[j&7]*(*pc++); + fskd->fmyv[j&7] = s; + fskd->fmp++; + fskd->fmp &= 7; + return s; +} + +/*! Band-pass filter for SPACE frequency */ +static inline float filterS(fsk_data *fskd,float in) +{ + int i, j; + double s; + double *pc; + + pc = &coef_in[fskd->f_space_idx][fskd->bw][0]; + fskd->fsxv[(fskd->fsp+6)&7] = in*(*pc++); + + s = (fskd->fsxv[(fskd->fsp + 6) & 7] - fskd->fsxv[fskd->fsp]) + 3 * (fskd->fsxv[(fskd->fsp + 2) & 7] - fskd->fsxv[(fskd->fsp + 4) & 7]); + for (i = 0, j = fskd->fsp; i < 6; i++, j++) + s += fskd->fsyv[j&7]*(*pc++); + fskd->fsyv[j&7] = s; + fskd->fsp++; + fskd->fsp &= 7; + return s; +} + +/*! Low-pass filter for demodulated data */ +static inline float filterL(fsk_data *fskd,float in) +{ + int i, j; + double s; + double *pc; + + pc = &coef_out[fskd->bw][0]; + fskd->flxv[(fskd->flp + 6) & 7] = in * (*pc++); + + s = (fskd->flxv[fskd->flp] + fskd->flxv[(fskd->flp+6)&7]) + + 6 * (fskd->flxv[(fskd->flp+1)&7] + fskd->flxv[(fskd->flp+5)&7]) + + 15 * (fskd->flxv[(fskd->flp+2)&7] + fskd->flxv[(fskd->flp+4)&7]) + + 20 * fskd->flxv[(fskd->flp+3)&7]; + + for (i = 0,j = fskd->flp;i<6;i++,j++) + s += fskd->flyv[j&7]*(*pc++); + fskd->flyv[j&7] = s; + fskd->flp++; + fskd->flp &= 7; + return s; +} + +static inline int demodulator(fsk_data *fskd, float *retval, float x) +{ + float xS,xM; + + fskd->cola_in[fskd->pcola] = x; + + xS = filterS(fskd,x); + xM = filterM(fskd,x); + + fskd->cola_filter[fskd->pcola] = xM-xS; + + x = filterL(fskd,xM*xM - xS*xS); + + fskd->cola_demod[fskd->pcola++] = x; + fskd->pcola &= (NCOLA-1); + + *retval = x; + return 0; +} + +static int get_bit_raw(fsk_data *fskd, short *buffer, int *len) +{ + /* This function implements a DPLL to synchronize with the bits */ + float x,spb,spb2,ds; + int f; + + spb = fskd->spb; + if (fskd->spb == 7) + spb = 8000.0 / 1200.0; + ds = spb/32.; + spb2 = spb/2.; + + for (f = 0;;) { + if (demodulator(fskd, &x, GET_SAMPLE)) + return -1; + if ((x * fskd->x0) < 0) { /* Transition */ + if (!f) { + if (fskd->cont<(spb2)) + fskd->cont += ds; + else + fskd->cont -= ds; + f = 1; + } + } + fskd->x0 = x; + fskd->cont += 1.; + if (fskd->cont > spb) { + fskd->cont -= spb; + break; + } + } + f = (x > 0) ? 0x80 : 0; + return f; +} + +int fsk_serial(fsk_data *fskd, short *buffer, int *len, int *outbyte) +{ + int a; + int i,j,n1,r; + int samples = 0; + int olen; + int beginlen=*len; + int beginlenx; + + switch (fskd->state) { + /* Pick up where we left off */ + case STATE_SEARCH_STARTBIT2: + goto search_startbit2; + case STATE_SEARCH_STARTBIT3: + goto search_startbit3; + case STATE_GET_BYTE: + goto getbyte; + } + /* We await for start bit */ + do { + /* this was jesus's nice, reasonable, working (at least with RTTY) code + to look for the beginning of the start bit. Unfortunately, since TTY/TDD's + just start sending a start bit with nothing preceding it at the beginning + of a transmission (what a LOSING design), we cant do it this elegantly */ + /* + if (demodulator(zap,&x1)) return(-1); + for (;;) { + if (demodulator(zap,&x2)) return(-1); + if (x1>0 && x2<0) break; + x1 = x2; + } + */ + /* this is now the imprecise, losing, but functional code to detect the + beginning of a start bit in the TDD sceanario. It just looks for sufficient + level to maybe, perhaps, guess, maybe that its maybe the beginning of + a start bit, perhaps. This whole thing stinks! */ + beginlenx=beginlen; /* just to avoid unused war warnings */ + if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) + return -1; + samples++; + for (;;) { +search_startbit2: + if (*len <= 0) { + fskd->state = STATE_SEARCH_STARTBIT2; + return 0; + } + samples++; + if (demodulator(fskd, &fskd->x2, GET_SAMPLE)) + return(-1); +#if 0 + printf("x2 = %5.5f ", fskd->x2); +#endif + if (fskd->x2 < -0.5) + break; + } +search_startbit3: + /* We await for 0.5 bits before using DPLL */ + i = fskd->spb/2; + if (*len < i) { + fskd->state = STATE_SEARCH_STARTBIT3; + return 0; + } + for (; i>0; i--) { + if (demodulator(fskd, &fskd->x1, GET_SAMPLE)) + return(-1); +#if 0 + printf("x1 = %5.5f ", fskd->x1); +#endif + samples++; + } + + /* x1 must be negative (start bit confirmation) */ + + } while (fskd->x1 > 0); + fskd->state = STATE_GET_BYTE; + +getbyte: + + /* Need at least 80 samples (for 1200) or + 1320 (for 45.5) to be sure we'll have a byte */ + if (fskd->nbit < 8) { + if (*len < 1320) + return 0; + } else { + if (*len < 80) + return 0; + } + /* Now we read the data bits */ + j = fskd->nbit; + for (a = n1 = 0; j; j--) { + olen = *len; + i = get_bit_raw(fskd, buffer, len); + buffer += (olen - *len); + if (i == -1) + return(-1); + if (i) + n1++; + a >>= 1; + a |= i; + } + j = 8-fskd->nbit; + a >>= j; + + /* We read parity bit (if exists) and check parity */ + if (fskd->parity) { + olen = *len; + i = get_bit_raw(fskd, buffer, len); + buffer += (olen - *len); + if (i == -1) + return(-1); + if (i) + n1++; + if (fskd->parity == 1) { /* parity=1 (even) */ + if (n1&1) + a |= 0x100; /* error */ + } else { /* parity=2 (odd) */ + if (!(n1&1)) + a |= 0x100; /* error */ + } + } + + /* We read STOP bits. All of them must be 1 */ + + for (j = fskd->nstop;j;j--) { + r = get_bit_raw(fskd, buffer, len); + if (r == -1) + return(-1); + if (!r) + a |= 0x200; + } + + /* And finally we return */ + /* Bit 8 : Parity error */ + /* Bit 9 : Framming error*/ + + *outbyte = a; + fskd->state = STATE_SEARCH_STARTBIT; + return 1; +} -- cgit v1.2.3