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M17 - Audio RF Modulation(WIP);

This commit is contained in:
lwvmobile 2024-03-07 01:24:59 -05:00
parent 72ac2f628b
commit 11a08298ff
1 changed files with 45 additions and 4 deletions
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49
src/m17.c
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@ -1007,7 +1007,7 @@ const int8_t symbol_map[4] = {+1, +3, -1, -3};
void encodeM17RF (dsd_opts * opts, dsd_state * state, uint8_t * input, int type)
{
int i;
int i, j;
//LSF frame sync pattern - 0x55F7 +3, +3, +3, +3, -3, -3, +3, -3
uint8_t m17_lsf_fs[16] = {0,1,0,1,0,1,0,1,1,1,1,1,0,1,1,1};
@ -1042,7 +1042,7 @@ void encodeM17RF (dsd_opts * opts, dsd_state * state, uint8_t * input, int type)
output_dibits[i+8] = (input[i*2+0] << 1) + (input[i*2+1] << 0);
//convert to symbols
int output_symbols[192]; memset (output_symbols, 0, sizeof(output_symbols)); UNUSED(output_symbols);
int output_symbols[192]; memset (output_symbols, 0, 192*sizeof(int));
for (i = 0; i < 192; i++)
output_symbols[i] = symbol_map[output_dibits[i]];
@ -1061,8 +1061,49 @@ void encodeM17RF (dsd_opts * opts, dsd_state * state, uint8_t * input, int type)
fputc (output_dibits[i], opts->symbol_out_f);
}
//TODO: symbols to audio
UNUSED(opts); UNUSED(state);
//WIP: symbols to audio
//upsample 10x
int output_up[192*10]; memset (output_up, 0, 192*10*sizeof(int));
for (i = 0; i < 192; i++)
{
for (j = 0; j < 10; j++)
output_up[(i*10)+j] = output_symbols[i];
}
//debug upsample
// fprintf (stderr, "\n up:");
// for (i = 0; i < 1920; i++)
// {
// if (i%24 == 0) fprintf (stderr, "\n");
// fprintf (stderr, " %d", output_up[i]);
// }
//filter + gain (voltage) //m17_filter
short baseband[1920]; memset (baseband, 0, 1920*sizeof(short));
for (i = 0; i < 1920; i++)
{
baseband[i] = output_up[i] * 10000; //optimal value?
baseband[i] = m17_filter(baseband[i]);
}
//debug baseband
// fprintf (stderr, "\n bb:");
// for (i = 0; i < 1920; i++)
// {
// if (i%24 == 0) fprintf (stderr, "\n");
// fprintf (stderr, " %d", baseband[i]);
// }
//test playing back this audio now -- working and sync achieved, yay!
if (opts->audio_out_type == 0 && opts->monitor_input_audio == 1) //TODO: Open the analog output device, use -8 for now
{
pa_simple_write(opts->pulse_raw_dev_out, baseband, 1920*2, NULL);
}
//TODO: Other audio output methods, probably just the 'analog' out and stdout? or something?
//NOTE: May need to disable the debug decoding when playing out real audio?
UNUSED(state);
}