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

1 files changed, 360 insertions, 0 deletions

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 <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 <stdio.h>
+
+#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;
+}