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flightgear/src/Sound/morse.cxx
curt 6e91c958e3 Play the full 4x VOR and 1x DME morse ident sequence at 30 second intervals. 
When you tune into a station start at a "random" point in the sequence.
Sped up the words per minute to 13 to which means one sequence per about 4 secs.
This means we get through the whole sequence in about 20 seconds leaving 10
seconds of silence.
2001-03-09 23:35:21 +00:00

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// 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"
static const 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 */
};
// constructor
FGMorse::FGMorse() {
}
// destructor
FGMorse::~FGMorse() {
}
// allocate and initialize sound samples
bool FGMorse::init() {
int i, j;
// Make Low DIT
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI
/ (8000.0 / LO_FREQUENCY) ) )
* ((double)i / TRANSITION_BYTES)
/ 2.0 + 0.5;
/* Convert to unsigned byte */
lo_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 / LO_FREQUENCY) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
lo_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 / LO_FREQUENCY) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
lo_dit[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( i = DIT_SIZE - COUNT_SIZE; i < DIT_SIZE; ++i ) {
lo_dit[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
}
// Make High DIT
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI
/ (8000.0 / HI_FREQUENCY)) )
* ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
/* Convert to unsigned byte */
hi_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 / HI_FREQUENCY) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
hi_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 / HI_FREQUENCY) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
hi_dit[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( i = DIT_SIZE - COUNT_SIZE; i < DIT_SIZE; ++i ) {
hi_dit[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
}
// Make Low DAH
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI
/ (8000.0 / LO_FREQUENCY) ) )
* ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
/* Convert to unsigned byte */
lo_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 / LO_FREQUENCY) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
lo_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 / LO_FREQUENCY) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
lo_dah[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( int i = DAH_SIZE - COUNT_SIZE; i < DAH_SIZE; ++i ) {
lo_dah[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
}
// Make High DAH
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI
/ (8000.0 / HI_FREQUENCY) ) )
* ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
/* Convert to unsigned byte */
hi_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 / HI_FREQUENCY) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
hi_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 / HI_FREQUENCY) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
hi_dah[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( int i = DAH_SIZE - COUNT_SIZE; i < DAH_SIZE; ++i ) {
hi_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;
}
// allocate and initialize sound samples
bool FGMorse::cust_init(const int freq ) {
int i, j;
// Make DIT
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / freq)) )
* ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
/* Convert to unsigned byte */
cust_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 / freq) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
cust_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 / freq) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
cust_dit[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( i = DIT_SIZE - COUNT_SIZE; i < DIT_SIZE; ++i ) {
cust_dit[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
}
// Make DAH
for ( i = 0; i < TRANSITION_BYTES; ++i ) {
float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / freq) ) )
* ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
/* Convert to unsigned byte */
cust_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 / freq) ) )
/ 2.0 + 0.5;
/* Convert to unsigned byte */
cust_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 / freq) ) )
* ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
--j;
/* Convert to unsigned byte */
cust_dah[ i ] = (unsigned char) ( level * 255.0 ) ;
}
for ( int i = DAH_SIZE - COUNT_SIZE; i < DAH_SIZE; ++i ) {
cust_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;
}
// make a FGSimpleSound morse code transmission for the specified string
FGSimpleSound *FGMorse::make_ident( const string& id, const int freq ) {
char *idptr = (char *)id.c_str();
int length = 0;
int i, j;
// 0. Select the frequency. If custom frequency, generate the
// sound fragments we need on the fly.
unsigned char *dit_ptr, *dah_ptr;
if ( freq == LO_FREQUENCY ) {
dit_ptr = lo_dit;
dah_ptr = lo_dah;
} else if ( freq == HI_FREQUENCY ) {
dit_ptr = hi_dit;
dah_ptr = hi_dah;
} else {
cust_init( freq );
dit_ptr = cust_dit;
dah_ptr = cust_dah;
}
// 1. Determine byte length of message
for ( i = 0; i < (int)id.length(); ++i ) {
if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
char c = idptr[i] - 'A';
for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
if ( alphabet[c][j] == DIT ) {
length += DIT_SIZE;
} else if ( alphabet[c][j] == DAH ) {
length += DAH_SIZE;
}
}
length += SPACE_SIZE;
} else {
// skip unknown character
}
}
// add 2x more space to the end of the string
length += 2 * SPACE_SIZE;
// 2. Allocate space for the message
unsigned char *buffer = new unsigned char[length];
// 3. Assemble the message;
unsigned char *buf_ptr = buffer;
for ( i = 0; i < (int)id.length(); ++i ) {
if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
char c = idptr[i] - 'A';
for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
if ( alphabet[c][j] == DIT ) {
memcpy( buf_ptr, dit_ptr, DIT_SIZE );
buf_ptr += DIT_SIZE;
} else if ( alphabet[c][j] == DAH ) {
memcpy( buf_ptr, dah_ptr, DAH_SIZE );
buf_ptr += DAH_SIZE;
}
}
memcpy( buf_ptr, space, SPACE_SIZE );
buf_ptr += SPACE_SIZE;
} else {
// skip unknown character
}
}
memcpy( buf_ptr, space, SPACE_SIZE );
buf_ptr += SPACE_SIZE;
memcpy( buf_ptr, space, SPACE_SIZE );
buf_ptr += SPACE_SIZE;
// 4. create the simple sound and return
FGSimpleSound *sample = new FGSimpleSound( buffer, length );
return sample;
}
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