--- /dev/null
+// morse.cxx -- Morse code generation class
+//
+// Written by Curtis Olson, started March 2001.
+//
+// Copyright (C) 2001 Curtis L. Olson - curt@flightgear.org
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+//
+// $Id$
+
+
+#include "morse.hxx"
+
+
+// constructor
+FGMorse::FGMorse() {
+}
+
+// destructor
+FGMorse::~FGMorse() {
+}
+
+
+// allocate and initialize sound samples
+bool FGMorse::init() {
+ int i, j;
+
+ // Make DIT
+ unsigned char dit[ DIT_SIZE ] ;
+ for ( i = 0; i < TRANSITION_BYTES; ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY)) )
+ * ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
+
+ /* Convert to unsigned byte */
+ dit[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+
+ for ( i = TRANSITION_BYTES;
+ i < DIT_SIZE - TRANSITION_BYTES - COUNT_SIZE; ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
+ / 2.0 + 0.5;
+
+ /* Convert to unsigned byte */
+ dit[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+ j = TRANSITION_BYTES;
+ for ( i = DIT_SIZE - TRANSITION_BYTES - COUNT_SIZE;
+ i < DIT_SIZE - COUNT_SIZE;
+ ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
+ * ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
+ --j;
+
+ /* Convert to unsigned byte */
+ dit[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+ for ( i = DIT_SIZE - COUNT_SIZE; i < DIT_SIZE; ++i ) {
+ dit[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
+ }
+
+ // Make DAH
+ unsigned char dah[ DAH_SIZE ] ;
+ for ( i = 0; i < TRANSITION_BYTES; ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
+ * ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
+
+ /* Convert to unsigned byte */
+ dah[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+
+ for ( i = TRANSITION_BYTES;
+ i < DAH_SIZE - TRANSITION_BYTES - COUNT_SIZE;
+ ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
+ / 2.0 + 0.5;
+
+ /* Convert to unsigned byte */
+ dah[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+ j = TRANSITION_BYTES;
+ for ( int i = DAH_SIZE - TRANSITION_BYTES - COUNT_SIZE;
+ i < DAH_SIZE - COUNT_SIZE;
+ ++i ) {
+ float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
+ * ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
+ --j;
+
+ /* Convert to unsigned byte */
+ dah[ i ] = (unsigned char) ( level * 255.0 ) ;
+ }
+ for ( int i = DAH_SIZE - COUNT_SIZE; i < DAH_SIZE; ++i ) {
+ dah[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
+ }
+
+ // Make SPACE
+ for ( int i = 0; i < SPACE_SIZE; ++i ) {
+ space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
+ }
+
+ return true;
+}
--- /dev/null
+// morse.hxx -- Morse code generation class
+//
+// Written by Curtis Olson, started March 2001.
+//
+// Copyright (C) 2001 Curtis L. Olson - curt@flightgear.org
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+//
+// $Id$
+
+
+#ifndef _MORSE_HXX
+#define _MORSE_HXX
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <simgear/compiler.h>
+
+#include <plib/sl.h>
+#include <plib/sm.h>
+
+
+// Quoting from http://www.kluft.com/~ikluft/ham/morse-intro.html by
+// Ian Kluft KO6YQ <ikluft@kluft.com>
+//
+// [begin quote]
+//
+// What is the Standard for Measuring Morse Code Speed?
+//
+// [This was adapted from the Ham Radio FAQ which used to be posted on UseNet.]
+//
+// The word PARIS was chosen as the standard length for CW code
+// speed. Each dit counts for one count, each dah counts for three
+// counts, intra-character spacing is one count, inter-character
+// spacing is three counts and inter-word spacing is seven counts, so
+// the word PARIS is exactly 50 counts:
+//
+// PPPPPPPPPPPPPP AAAAAA RRRRRRRRRR IIIIII SSSSSSSSSS
+// di da da di di da di da di di di di di di
+// 1 1 3 1 3 1 1 3 1 1 3 3 1 1 3 1 1 3 1 1 1 3 1 1 1 1 1 7 = 50
+// ^ ^ ^
+// ^Intra-character ^Inter-character Inter-word^
+//
+// So 5 words-per-minute = 250 counts-per-minute / 50 counts-per-word
+// or one count every 240 milliseconds. 13 words-per-minute is one
+// count every ~92.3 milliseconds. This method of sending code is
+// sometimes called "Slow Code", because at 5 wpm it sounds VERY SLOW.
+//
+// The "Farnsworth" method is accomplished by sending the dits and
+// dahs and intra-character spacing at a higher speed, then increasing
+// the inter-character and inter-word spacing to slow the sending
+// speed down to the desired speed. For example, to send at 5 wpm with
+// 13 wpm characters in Farnsworth method, the dits and
+// intra-character spacing would be 92.3 milliseconds, the dah would
+// be 276.9 milliseconds, the inter-character spacing would be 1.443
+// seconds and inter-word spacing would be 3.367 seconds.
+//
+// [end quote]
+
+// Ok, back to Curt
+
+// My formulation is based dit = 1 count, dah = 3 counts, 1 count for
+// intRA-character space, 3 counts for intER-character space. Target
+// is 5 wpm which by the above means 1 count = 240 milliseconds.
+//
+// AIM 1-1-7 (f) states that the frequency of the tone should be 1020
+// Hz for the VOR ident.
+
+
+static const char DI = '1';
+static const char DIT = '1';
+static const char DA = '2';
+static const char DAH = '2';
+static const char end = '0';
+
+static const int BYTES_PER_SECOND = 8000;
+static const int BEAT_LENGTH = 240; // milleseconds (5 wpm)
+static const int TRANSITION_BYTES = 40;
+static const int COUNT_SIZE = BYTES_PER_SECOND * BEAT_LENGTH / 1000;
+static const int DIT_SIZE = 2 * COUNT_SIZE; // 2 counts
+static const int DAH_SIZE = 4 * COUNT_SIZE; // 4 counts
+static const int SPACE_SIZE = 3 * COUNT_SIZE; // 3 counts
+static const int FREQUENCY = 1020; // AIM 1-1-7 (f) specified in Hz
+
+static char alphabet[26][4] = {
+ { DI, DAH, end, end }, /* A */
+ { DA, DI, DI, DIT }, /* B */
+ { DA, DI, DA, DIT }, /* C */
+ { DA, DI, DIT, end }, /* D */
+ { DIT, end, end, end }, /* E */
+ { DI, DI, DA, DIT }, /* F */
+ { DA, DA, DIT, end }, /* G */
+ { DI, DI, DI, DIT }, /* H */
+ { DI, DIT, end, end }, /* I */
+ { DI, DA, DA, DAH }, /* J */
+ { DA, DI, DAH, end }, /* K */
+ { DI, DA, DI, DIT }, /* L */
+ { DA, DAH, end, end }, /* M */
+ { DA, DIT, end, end }, /* N */
+ { DA, DA, DAH, end }, /* O */
+ { DI, DA, DA, DIT }, /* P */
+ { DA, DA, DI, DAH }, /* Q */
+ { DI, DA, DIT, end }, /* R */
+ { DI, DI, DIT, end }, /* S */
+ { DAH, end, end, end }, /* T */
+ { DI, DI, DAH, end }, /* U */
+ { DI, DI, DI, DAH }, /* V */
+ { DI, DA, DAH, end }, /* W */
+ { DA, DI, DI, DAH }, /* X */
+ { DA, DI, DA, DAH }, /* Y */
+ { DA, DA, DI, DIT } /* Z */
+};
+
+// manages everything we need to know for an individual sound sample
+class FGMorse {
+
+ unsigned char dit[ DIT_SIZE ] ;
+ unsigned char dah[ DAH_SIZE ] ;
+ unsigned char space[ SPACE_SIZE ] ;
+
+public:
+
+ FGMorse();
+ ~FGMorse();
+
+ // allocate and initialize sound samples
+ bool init();
+};
+
+
+#endif // _MORSE_HXX
+
+
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