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minimodem: fsk_transmit_frame factored out

This commit is contained in:
Kamal Mostafa 2013-06-08 10:04:06 -07:00
parent 8876f6674a
commit 24f1acff4f
1 changed files with 30 additions and 14 deletions
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44
src/minimodem.c
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@ -72,6 +72,32 @@ tx_stop_transmit_sighandler( int sig )
/*
* rudimentary BFSK transmitter
*/
static void fsk_transmit_frame(
simpleaudio *sa_out,
unsigned int bits,
unsigned int n_data_bits,
size_t bit_nsamples,
float bfsk_mark_f,
float bfsk_space_f,
float bfsk_nstartbits,
float bfsk_nstopbits
)
{
int i;
if ( bfsk_nstartbits > 0 )
simpleaudio_tone(sa_out, bfsk_space_f,
bit_nsamples * bfsk_nstartbits); // start
for ( i=0; i<n_data_bits; i++ ) { // data
unsigned int bit = ( bits >> i ) & 1;
float tone_freq = bit == 1 ? bfsk_mark_f : bfsk_space_f;
simpleaudio_tone(sa_out, tone_freq, bit_nsamples);
}
if ( bfsk_nstopbits > 0 )
simpleaudio_tone(sa_out, bfsk_mark_f,
bit_nsamples * bfsk_nstopbits); // stop
}
static void fsk_transmit_stdin(
simpleaudio *sa_out,
int tx_interactive,
@ -125,20 +151,10 @@ static void fsk_transmit_stdin(
simpleaudio_tone(sa_out, bfsk_mark_f, bit_nsamples);
}
unsigned int j;
for ( j=0; j<nwords; j++ ) {
if ( bfsk_nstartbits > 0 )
simpleaudio_tone(sa_out, bfsk_space_f,
bit_nsamples * bfsk_nstartbits); // start
int i;
for ( i=0; i<n_data_bits; i++ ) { // data
unsigned int bit = ( bits[j] >> i ) & 1;
float tone_freq = bit == 1 ? bfsk_mark_f : bfsk_space_f;
simpleaudio_tone(sa_out, tone_freq, bit_nsamples);
}
if ( bfsk_nstopbits > 0 )
simpleaudio_tone(sa_out, bfsk_mark_f,
bit_nsamples * bfsk_nstopbits); // stop
}
for ( j=0; j<nwords; j++ )
fsk_transmit_frame(sa_out, bits[j], n_data_bits,
bit_nsamples, bfsk_mark_f, bfsk_space_f,
bfsk_nstartbits, bfsk_nstopbits);
if ( tx_interactive )
setitimer(ITIMER_REAL, &itv, NULL);