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-rw-r--r--trunk/main/fskmodem.c360
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diff --git a/trunk/main/fskmodem.c b/trunk/main/fskmodem.c
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+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 1999 - 2005, Digium, Inc.
+ *
+ * Mark Spencer <markster@digium.com>
+ *
+ * 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 <markster@digium.com>
+ *
+ * \arg Includes code and algorithms from the Zapata library.
+ *
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#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 int iget_sample(short **buffer, int *len)
+{
+ int retval;
+ retval = (int) **buffer;
+ (*buffer)++;
+ (*len)--;
+ return retval;
+}
+
+#define IGET_SAMPLE iget_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
+ },
+};
+
+/*! Integer Pass Band demodulator filter */
+static inline int ibpdfilter(struct filter_struct * fs, int in)
+{
+ int i,j;
+ int s;
+ int64_t s_interim;
+
+ /* integer filter */
+ s = in * fs->icoefs[0];
+ fs->ixv[(fs->ip+6)&7] = s;
+
+ s= (fs->ixv[fs->ip] + fs->ixv[(fs->ip+6)&7]) +
+ 6 * (fs->ixv[(fs->ip+1)&7] + fs->ixv[(fs->ip+5)&7]) +
+ 15 * (fs->ixv[(fs->ip+2)&7] + fs->ixv[(fs->ip+4)&7]) +
+ 20 * fs->ixv[(fs->ip+3)&7];
+
+ for (i=1, j=fs->ip; i < 7; i++,j++) {
+ /* Promote operation to 64 bit to prevent overflow that occurred in 32 bit) */
+ s_interim = (int64_t)(fs->iyv[j & 7]) *
+ (int64_t)(fs->icoefs[i]) /
+ (int64_t)(1024);
+ s += (int) s_interim;
+ }
+ fs->iyv[ j & 7] = s;
+ fs->ip++;
+ fs->ip &= 7;
+ return s;
+}
+
+/*! Integer Band Pass filter */
+static inline int ibpfilter(struct filter_struct * fs, int in)
+{
+ int i, j;
+ int s;
+ int64_t s_interim;
+
+ /* integer filter */
+ s = in * fs->icoefs[0] / 256;
+ fs->ixv[(fs->ip+6) & 7] = s;
+
+ s = (fs->ixv[(fs->ip+6) & 7] - fs->ixv[fs->ip])
+ + 3 * (fs->ixv[(fs->ip+2) & 7] - fs->ixv[(fs->ip+4) & 7]);
+
+ for (i=1,j=fs->ip; i < 7; i++,j++) {
+ s_interim = (int64_t)(fs->iyv[j&7]) *
+ (int64_t)(fs->icoefs[i]) /
+ (int64_t)(256);
+ s+= (int) s_interim;
+ }
+ fs->iyv[j&7]=s;
+ fs->ip++; fs->ip &= 7;
+ return s;
+}
+
+static inline int idemodulator(fsk_data *fskd, int *retval, int x)
+{
+ int is, im, id;
+ int ilin2;
+
+ is = ibpfilter(&fskd->space_filter, x);
+ im = ibpfilter(&fskd->mark_filter, x);
+
+ ilin2 = ((im * im) - (is * is))/(256 * 256);
+
+ id = ibpdfilter(&fskd->demod_filter, ilin2);
+
+ *retval = id;
+ return 0;
+}
+
+static int get_bit_raw(fsk_data *fskd, short *buffer, int *len)
+{
+ /* This function implements a DPLL to synchronize with the bits */
+ int f;
+
+ int ix;
+ /* PLL coeffs are set up in callerid_new */
+ for (f = 0;;){
+ if (idemodulator(fskd, &ix, IGET_SAMPLE)) return(-1);
+ if ((ix * fskd->xi0)<0) { /* Transicion */
+ if (!f) {
+ if (fskd->icont<(fskd->pllispb2))
+ fskd->icont+=fskd->pllids;
+ else
+ fskd->icont-=fskd->pllids;
+ f = 1;
+ }
+ }
+ fskd->xi0=ix;
+ fskd->icont+=32;
+ if (fskd->icont>fskd->pllispb) {
+ fskd->icont-=fskd->pllispb;
+ break;
+ }
+ }
+ f=(ix>0)?0x80:0;
+ return f;
+}
+
+int fskmodem_init(fsk_data *fskd)
+{
+ int i;
+
+ fskd->space_filter.ip = 0;
+ fskd->mark_filter.ip = 0;
+ fskd->demod_filter.ip = 0;
+
+ for ( i = 0 ; i < 7 ; i++ ) {
+ fskd->space_filter.icoefs[i] =
+ coef_in[fskd->f_space_idx][fskd->bw][i] * 256;
+ fskd->space_filter.ixv[i] = 0;;
+ fskd->space_filter.iyv[i] = 0;;
+
+ fskd->mark_filter.icoefs[i] =
+ coef_in[fskd->f_mark_idx][fskd->bw][i] * 256;
+ fskd->mark_filter.ixv[i] = 0;;
+ fskd->mark_filter.iyv[i] = 0;;
+
+ fskd->demod_filter.icoefs[i] =
+ coef_out[fskd->bw][i] * 1024;
+ fskd->demod_filter.ixv[i] = 0;;
+ fskd->demod_filter.iyv[i] = 0;;
+ }
+ return 0;
+}
+
+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 */
+ /* NOT USED
+ 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 (idemodulator(fskd, &fskd->xi1, IGET_SAMPLE))
+ return -1;
+ samples++;
+ for(;;) {
+search_startbit2:
+ if (*len <= 0) {
+ fskd->state = STATE_SEARCH_STARTBIT2;
+ return 0;
+ }
+ samples++;
+ if (idemodulator(fskd,&fskd->xi2,IGET_SAMPLE))
+ return -1;
+#if 0
+ printf("xi2 = %d ", fskd->xi2);
+#endif
+ if (fskd->xi2 < 512)
+ break;
+ }
+search_startbit3:
+ /* We await for 0.5 bits before using DPLL */
+ i=fskd->ispb/2;
+ if (*len < i) {
+ fskd->state = STATE_SEARCH_STARTBIT3;
+ return 0;
+ }
+ for (; i>0; i--) {
+ if (idemodulator(fskd, &fskd->xi1, IGET_SAMPLE))
+ return(-1);
+#if 0
+ printf("xi1 = %d ", fskd->xi1);
+#endif
+ samples++;
+ }
+
+ /* x1 must be negative (start bit confirmation) */
+
+ } while (fskd->xi1>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->instop; 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;
+}