mirror of
https://github.com/lwvmobile/dsd-fme.git
synced 2026-11-15 02:07:24 -05:00
M17 More Work and Fixes; #152
This commit is contained in:
lwvmobile
452
src/m17.c
452
src/m17.c
@@ -2,8 +2,8 @@
|
||||
* m17.c
|
||||
* M17 Decoder (WIP)
|
||||
*
|
||||
* M17_SCRAMBLER (m17_scramble) Bit Array from SDR++
|
||||
* Base40 CharMap from m17-tools
|
||||
* m17_scramble Bit Array from SDR++
|
||||
* CRC16 from M17-Implementations (thanks again, sp5wwp)
|
||||
*
|
||||
* LWVMOBILE
|
||||
* 2023-07 DSD-FME Florida Man Edition
|
||||
@@ -37,32 +37,97 @@ uint8_t m17_scramble[369] = {
|
||||
0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1
|
||||
};
|
||||
|
||||
char b40[41] = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/.";
|
||||
char b40[] = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/.";
|
||||
|
||||
/*
|
||||
2.5.4
|
||||
LSF CRC
|
||||
M17 uses a non-standard version of 16-bit CRC with polynomial x16 + x14 + x12 + x11 + x8 +
|
||||
x5 + x4 + x2 + 1 or 0×5935 and initial value of 0×FFFF. This polynomial allows for detecting all
|
||||
errors up to hamming distance of 5 with payloads up to 241 bits, which is less than the amount
|
||||
of data in each frame.
|
||||
*/
|
||||
uint8_t p1[62] = {
|
||||
1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1,
|
||||
1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1,
|
||||
0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1
|
||||
};
|
||||
|
||||
uint16_t crc16m17(const uint8_t buf[], int len)
|
||||
//from M17_Implementations -- sp5wwp -- should have just looked here to begin with
|
||||
//this setup looks very similar to the OP25 variant of crc16, but with a few differences (uses packed bytes)
|
||||
uint16_t crc16m17(const uint8_t *in, const uint16_t len)
|
||||
{
|
||||
uint32_t crc = 0xFFFF; //init val
|
||||
uint16_t poly = 0x5935;
|
||||
uint16_t crc = 0xFFFF;
|
||||
for(int i=0; i<len; i++)
|
||||
for(uint16_t i=0; i<len; i++)
|
||||
{
|
||||
uint8_t bit = buf[i] & 1;
|
||||
crc = ((crc << 1) | bit) & 0x1ffff;
|
||||
if (crc & 0x10000) crc = (crc & 0xffff) ^ poly;
|
||||
crc^=in[i]<<8;
|
||||
for(uint8_t j=0; j<8; j++)
|
||||
{
|
||||
crc<<=1;
|
||||
if(crc&0x10000)
|
||||
crc=(crc^poly)&0xFFFF;
|
||||
}
|
||||
}
|
||||
|
||||
return crc & 0xffff;
|
||||
return crc&(0xFFFF);
|
||||
}
|
||||
|
||||
void M17decodeLSF(dsd_state * state, dsd_opts * opts)
|
||||
void M17decodeCSD(dsd_state * state, unsigned long long int dst, unsigned long long int src)
|
||||
{
|
||||
//evaluate dst and src, and determine if they need to be converted to calsign
|
||||
int i, j;
|
||||
char c;
|
||||
unsigned long long int value;
|
||||
|
||||
if (dst == 0xFFFFFFFFFFFF)
|
||||
fprintf (stderr, " DST: BROADCAST");
|
||||
else if (dst == 0)
|
||||
fprintf (stderr, " DST: RESERVED %012llx", dst);
|
||||
else if (dst >= 0xEE6B28000000)
|
||||
fprintf (stderr, " DST: RESERVED %012llx", dst);
|
||||
else
|
||||
{
|
||||
fprintf (stderr, " DST: ");
|
||||
for (i = 0; i < 9; i++)
|
||||
{
|
||||
c = b40[dst % 40];
|
||||
state->m17_dst_csd[i] = c;
|
||||
fprintf (stderr, "%c", c);
|
||||
dst = dst / 40;
|
||||
}
|
||||
//assign completed CSD to a more useful string instead
|
||||
sprintf (state->m17_dst_str, "%c%c%c%c%c%c%c%c%c\0",
|
||||
state->m17_dst_csd[0], state->m17_dst_csd[1], state->m17_dst_csd[2], state->m17_dst_csd[3],
|
||||
state->m17_dst_csd[4], state->m17_dst_csd[5], state->m17_dst_csd[6], state->m17_dst_csd[7], state->m17_dst_csd[8]);
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, "DT: %s", state->m17_dst_str);
|
||||
}
|
||||
|
||||
if (src == 0xFFFFFFFFFFFF)
|
||||
fprintf (stderr, " SRC: UNKNOWN FFFFFFFFFFFF");
|
||||
else if (src == 0)
|
||||
fprintf (stderr, " SRC: RESERVED %012llx", src);
|
||||
else if (src >= 0xEE6B28000000)
|
||||
fprintf (stderr, " SRC: RESERVED %012llx", src);
|
||||
else
|
||||
{
|
||||
fprintf (stderr, " SRC: ");
|
||||
for (i = 0; i < 9; i++)
|
||||
{
|
||||
c = b40[src % 40];
|
||||
state->m17_src_csd[i] = c;
|
||||
fprintf (stderr, "%c", c);
|
||||
src = src / 40;
|
||||
}
|
||||
//assign completed CSD to a more useful string instead
|
||||
sprintf (state->m17_src_str, "%c%c%c%c%c%c%c%c%c\0",
|
||||
state->m17_src_csd[0], state->m17_src_csd[1], state->m17_src_csd[2], state->m17_src_csd[3],
|
||||
state->m17_src_csd[4], state->m17_src_csd[5], state->m17_src_csd[6], state->m17_src_csd[7], state->m17_src_csd[8]);
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, "ST: %s", state->m17_src_str);
|
||||
}
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, " DST: %012llX SRC: %012llX", state->m17_dst, state->m17_src);
|
||||
|
||||
}
|
||||
|
||||
void M17decodeLSF(dsd_state * state)
|
||||
{
|
||||
int i;
|
||||
|
||||
@@ -78,30 +143,56 @@ void M17decodeLSF(dsd_state * state, dsd_opts * opts)
|
||||
uint8_t lsf_cn = (lsf_type >> 7) & 0xF;
|
||||
uint8_t lsf_rs = (lsf_type >> 11) & 0x1F;
|
||||
|
||||
//store this so we can reference it for playing voice and/or decoding data
|
||||
//store this so we can reference it for playing voice and/or decoding data, dst/src etc
|
||||
state->m17_str_dt = lsf_dt;
|
||||
state->m17_dst = lsf_dst;
|
||||
state->m17_src = lsf_src;
|
||||
|
||||
fprintf (stderr, "\n");
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, " LSF TYPE: %04X", lsf_type);
|
||||
// if (lsf_ps == 0) fprintf (stderr, " PACKET - ");
|
||||
// if (lsf_ps == 1) fprintf (stderr, " STREAM - ");
|
||||
//packet or stream
|
||||
if (lsf_ps == 0) fprintf (stderr, " P-");
|
||||
if (lsf_ps == 1) fprintf (stderr, " S-");
|
||||
|
||||
//TODO: Base40 Callsigns
|
||||
fprintf (stderr, " CAN: %d", lsf_cn);
|
||||
fprintf (stderr, " DST: %012llX SRC: %012llX", lsf_dst, lsf_src);
|
||||
M17decodeCSD(state, lsf_dst, lsf_src);
|
||||
|
||||
if (lsf_et != 0) fprintf (stderr, " ENC");
|
||||
|
||||
if (lsf_dt == 0) fprintf (stderr, " Reserved");
|
||||
if (lsf_dt == 1) fprintf (stderr, " Data");
|
||||
if (lsf_dt == 2) fprintf (stderr, " Voice (3200bps)");
|
||||
if (lsf_dt == 3) fprintf (stderr, " Voice + Data");
|
||||
|
||||
if (lsf_et != 0) fprintf (stderr, " ENC");
|
||||
if (lsf_et == 1)
|
||||
fprintf (stderr, " Scrambler - %d", lsf_es);
|
||||
if (lsf_et == 2) fprintf (stderr, " AES-CTR");
|
||||
if (lsf_rs != 0) fprintf (stderr, " RS: %02X", lsf_rs);
|
||||
|
||||
if (lsf_et == 1) fprintf (stderr, " AES-CTR");
|
||||
if (lsf_et == 2) fprintf (stderr, " Scrambler - %d", lsf_es);
|
||||
|
||||
state->m17_enc = lsf_et;
|
||||
state->m17_enc_st = lsf_es;
|
||||
|
||||
//pack meta bits into 14 bytes
|
||||
for (i = 0; i < 14; i++)
|
||||
state->m17_meta[i] = (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[(i*8)+112], 8);
|
||||
|
||||
//Examine the Meta data
|
||||
if (lsf_et == 0 && state->m17_meta[0] != 0) //not sure if this applies universally, or just to text data byte 0 for null data
|
||||
{
|
||||
fprintf (stderr, " Meta:");
|
||||
if (lsf_es == 0) fprintf (stderr, " Text Data");
|
||||
if (lsf_es == 1) fprintf (stderr, " GNSS Pos");
|
||||
if (lsf_es == 2) fprintf (stderr, " Extended CSD");
|
||||
if (lsf_es == 3) fprintf (stderr, " Reserved");
|
||||
}
|
||||
|
||||
if (lsf_et == 1)
|
||||
{
|
||||
fprintf (stderr, " IV: ");
|
||||
for (i = 0; i < 14; i++)
|
||||
fprintf (stderr, "%02X", state->m17_meta[i]);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
int M17processLICH(dsd_state * state, dsd_opts * opts, uint8_t lich_bits[96])
|
||||
@@ -114,6 +205,10 @@ int M17processLICH(dsd_state * state, dsd_opts * opts, uint8_t lich_bits[96])
|
||||
uint8_t temp[96];
|
||||
bool g[4];
|
||||
|
||||
//for testing bit arrangement vs the crc code
|
||||
uint8_t bs[240];
|
||||
memset(bs, 1, sizeof(bs));
|
||||
|
||||
uint16_t crc_cmp = 0;
|
||||
uint16_t crc_ext = 0;
|
||||
uint8_t crc_err = 0;
|
||||
@@ -145,8 +240,7 @@ int M17processLICH(dsd_state * state, dsd_opts * opts, uint8_t lich_bits[96])
|
||||
fprintf (stderr, "LC: %d/6 ", lich_counter+1);
|
||||
else fprintf (stderr, "LICH G24 ERR");
|
||||
|
||||
//this is what 2.rrc is supposed to be -- according to m17-demod -- code fixed now and reflects this
|
||||
//SRC: AB2CDE, DEST: BROADCAST, STR:V/V, ENC:NONE, CAN:10, NONCE: 0000000000000000000000000000, CRC: 99af
|
||||
if (err = 0 && lich_reserve != 0) fprintf(stderr, " LRS: %d", lich_reserve);
|
||||
|
||||
//transfer to storage
|
||||
for (i = 0; i < 40; i++)
|
||||
@@ -159,15 +253,23 @@ int M17processLICH(dsd_state * state, dsd_opts * opts, uint8_t lich_bits[96])
|
||||
fprintf (stderr, "[%02X]", (uint8_t)ConvertBitIntoBytes(&lich_decoded[i*8], 8));
|
||||
}
|
||||
|
||||
uint8_t lsf_packed[30];
|
||||
memset (lsf_packed, 0, sizeof(lsf_packed));
|
||||
|
||||
if (lich_counter == 5)
|
||||
{
|
||||
crc_cmp = crc16m17 (state->m17_lsf, 240);
|
||||
|
||||
//need to pack bytes for the sw5wwp variant of the crc (might as well, may be useful in the future)
|
||||
for (i = 0; i < 30; i++)
|
||||
lsf_packed[i] = (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[i*8], 8);
|
||||
|
||||
crc_cmp = crc16m17(lsf_packed, 28);
|
||||
crc_ext = (uint16_t)ConvertBitIntoBytes(&state->m17_lsf[224], 16);
|
||||
|
||||
if (crc_cmp != crc_ext) crc_err = 1;
|
||||
|
||||
if (crc_err == 0)
|
||||
M17decodeLSF(state, opts);
|
||||
M17decodeLSF(state);
|
||||
|
||||
if (opts->payload == 1)
|
||||
{
|
||||
@@ -175,22 +277,29 @@ int M17processLICH(dsd_state * state, dsd_opts * opts, uint8_t lich_bits[96])
|
||||
for (i = 0; i < 30; i++)
|
||||
{
|
||||
if (i == 15) fprintf (stderr, "\n ");
|
||||
fprintf (stderr, "[%02X]", (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[i*8], 8));
|
||||
fprintf (stderr, "[%02X]", lsf_packed[i]);
|
||||
}
|
||||
}
|
||||
|
||||
// if (crc_err != 0)
|
||||
// fprintf (stderr, " %04X - %04X (CRC ERR)", crc_cmp, crc_ext);
|
||||
if (crc_err == 1) fprintf (stderr, " LSF CRC ERR");
|
||||
memset (state->m17_lsf, 1, sizeof(state->m17_lsf));
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, " E-%04X; C-%04X (CRC CHK)", crc_ext, crc_cmp);
|
||||
|
||||
if (crc_err == 1) fprintf (stderr, " EMB LSF CRC ERR");
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[128])
|
||||
void M17processCodec2_1600(dsd_opts * opts, dsd_state * state, uint8_t payload[128])
|
||||
{
|
||||
|
||||
//If payload is the same from the stream in this mode, I suppose we could use this area to parse
|
||||
//or send off the remaining data to be handled or decoded , or just print out the raw data bytes
|
||||
|
||||
int i;
|
||||
unsigned char voice1[8];
|
||||
unsigned char voice1[8]; //codec2_bytes_per_frame
|
||||
unsigned char voice2[8];
|
||||
|
||||
for (i = 0; i < 8; i++)
|
||||
@@ -199,8 +308,86 @@ void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[1
|
||||
voice2[i] = (unsigned char)ConvertBitIntoBytes(&payload[i*8+64], 8);
|
||||
}
|
||||
|
||||
//TODO: Either Make seperate 3200 and 1600 handling, or make this handle both
|
||||
//depends on how many bits 1600 needs and if its split the same as this
|
||||
//TODO: Add some decryption methods
|
||||
if (state->m17_enc != 0)
|
||||
{
|
||||
//process scrambler or AES-CTR decryption
|
||||
//(no AES-CTR right now, Scrambler should be easy enough)
|
||||
}
|
||||
|
||||
if (opts->payload == 1)
|
||||
{
|
||||
fprintf (stderr, "\n CODEC2: ");
|
||||
for (i = 0; i < 8; i++)
|
||||
fprintf (stderr, "%02X", voice1[i]);
|
||||
fprintf (stderr, " (1600)");
|
||||
|
||||
fprintf (stderr, "\n LSDATA: "); //low speed data
|
||||
for (i = 0; i < 8; i++)
|
||||
fprintf (stderr, "%02X", voice2[i]);
|
||||
}
|
||||
|
||||
#ifdef USE_CODEC2
|
||||
size_t nsam;
|
||||
nsam = 320; //codec2_samples_per_frame(state->codec2_1600);
|
||||
|
||||
short samp1[nsam];
|
||||
// short samp2[nsam];
|
||||
memset (samp1, 0, sizeof(samp1));
|
||||
// memset (samp2, 0, sizeof(samp2));
|
||||
|
||||
|
||||
codec2_decode(state->codec2_1600, samp1, voice1);
|
||||
// codec2_decode(state->codec2_1600, samp2, voice2);
|
||||
|
||||
|
||||
if (opts->audio_out_type == 0 && state->m17_enc == 0)
|
||||
{
|
||||
pa_simple_write(opts->pulse_digi_dev_out, samp1, nsam*2, NULL);
|
||||
// pa_simple_write(opts->pulse_digi_dev_out, samp2, nsam*2, NULL);
|
||||
}
|
||||
|
||||
if (opts->audio_out_type == 5 && state->m17_enc == 0)
|
||||
{
|
||||
write (opts->audio_out_fd, samp1, nsam*2);
|
||||
// write (opts->audio_out_fd, samp2, nsam*2);
|
||||
}
|
||||
|
||||
//WIP: Wav file saving -- still need a way to open/close/label wav files similar to call history
|
||||
if(opts->wav_out_f != NULL && state->m17_enc == 0)
|
||||
{
|
||||
sf_write_short(opts->wav_out_f, samp1, nsam);
|
||||
// sf_write_short(opts->wav_out_f, samp2, nsam);
|
||||
}
|
||||
|
||||
//TODO: Codec2 Raw file saving
|
||||
// if(mbe_out_dir)
|
||||
// {
|
||||
|
||||
// }
|
||||
|
||||
#endif
|
||||
|
||||
}
|
||||
|
||||
void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[128])
|
||||
{
|
||||
int i;
|
||||
unsigned char voice1[8]; //codec2_bytes_per_frame
|
||||
unsigned char voice2[8];
|
||||
|
||||
for (i = 0; i < 8; i++)
|
||||
{
|
||||
voice1[i] = (unsigned char)ConvertBitIntoBytes(&payload[i*8+0], 8);
|
||||
voice2[i] = (unsigned char)ConvertBitIntoBytes(&payload[i*8+64], 8);
|
||||
}
|
||||
|
||||
//TODO: Add some decryption methods
|
||||
if (state->m17_enc != 0)
|
||||
{
|
||||
//process scrambler or AES-CTR decryption
|
||||
//(no AES-CTR right now, Scrambler should be easy enough)
|
||||
}
|
||||
|
||||
if (opts->payload == 1)
|
||||
{
|
||||
@@ -215,10 +402,9 @@ void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[1
|
||||
fprintf (stderr, " (3200)");
|
||||
}
|
||||
|
||||
//TODO: Rework parts of this (we already know nsam = 160 on 3200 and 320 on 1600, etc)
|
||||
#ifdef USE_CODEC2
|
||||
size_t nsam;
|
||||
nsam = codec2_samples_per_frame(state->codec2_3200);
|
||||
nsam = 160; //codec2_samples_per_frame(state->codec2_3200);
|
||||
|
||||
short samp1[nsam];
|
||||
short samp2[nsam];
|
||||
@@ -230,20 +416,30 @@ void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[1
|
||||
codec2_decode(state->codec2_3200, samp2, voice2);
|
||||
|
||||
|
||||
if (opts->audio_out_type == 0)
|
||||
if (opts->audio_out_type == 0 && state->m17_enc == 0)
|
||||
{
|
||||
pa_simple_write(opts->pulse_digi_dev_out, samp1, nsam*2, NULL);
|
||||
pa_simple_write(opts->pulse_digi_dev_out, samp2, nsam*2, NULL);
|
||||
}
|
||||
|
||||
if (opts->audio_out_type == 5)
|
||||
if (opts->audio_out_type == 5 && state->m17_enc == 0)
|
||||
{
|
||||
write (opts->audio_out_fd, samp1, nsam*2);
|
||||
write (opts->audio_out_fd, samp2, nsam*2);
|
||||
}
|
||||
|
||||
//TODO: Wav file saving
|
||||
//WIP: Wav file saving -- still need a way to open/close/label wav files similar to call history
|
||||
if(opts->wav_out_f != NULL && state->m17_enc == 0)
|
||||
{
|
||||
sf_write_short(opts->wav_out_f, samp1, nsam);
|
||||
sf_write_short(opts->wav_out_f, samp2, nsam);
|
||||
}
|
||||
|
||||
//TODO: Codec2 Raw file saving
|
||||
// if(mbe_out_dir)
|
||||
// {
|
||||
|
||||
// }
|
||||
|
||||
#endif
|
||||
|
||||
@@ -251,13 +447,6 @@ void M17processCodec2_3200(dsd_opts * opts, dsd_state * state, uint8_t payload[1
|
||||
|
||||
void M17prepareStream(dsd_opts * opts, dsd_state * state, uint8_t m17_bits[368])
|
||||
{
|
||||
//this function will prepare Stream frames
|
||||
|
||||
// Scheme P2 is for frames (excluding LICH chunks, which are coded differently). This takes 296
|
||||
// encoded bits and selects 272 of them. Every 12th bit is being punctured out, leaving 272 bits.
|
||||
// The full matrix shall have 12 entries with 11 being ones.
|
||||
|
||||
// P2 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0]
|
||||
|
||||
int i, j, k, x;
|
||||
uint8_t m17_punc[310]; //25 * 11 = 275
|
||||
@@ -342,21 +531,22 @@ void M17prepareStream(dsd_opts * opts, dsd_state * state, uint8_t m17_bits[368])
|
||||
|
||||
if (state->m17_str_dt == 2)
|
||||
M17processCodec2_3200(opts, state, payload);
|
||||
else if (state->m17_str_dt == 3) fprintf (stderr, " V+D;"); //format not available yet in manual
|
||||
else if (state->m17_str_dt == 3)
|
||||
M17processCodec2_1600(opts, state, payload);
|
||||
else if (state->m17_str_dt == 1) fprintf (stderr, " DATA;");
|
||||
else if (state->m17_str_dt == 0) fprintf (stderr, " RES;");
|
||||
else fprintf (stderr, " UNK;");
|
||||
// else fprintf (stderr, " UNK;");
|
||||
|
||||
if (opts->payload == 1 && state->m17_str_dt != 2)
|
||||
if (opts->payload == 1 && state->m17_str_dt < 2)
|
||||
{
|
||||
fprintf (stderr, "\n STREAM: ");
|
||||
for (i = 0; i < 18; i++)
|
||||
fprintf (stderr, "[%02X]", (uint8_t)ConvertBitIntoBytes(&trellis_buf[i*8], 8));
|
||||
fprintf (stderr, "[%02X]", (uint8_t)ConvertBitIntoBytes(&trellis_buf[i*8], 8));
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
void processM17(dsd_opts * opts, dsd_state * state)
|
||||
void processM17STR(dsd_opts * opts, dsd_state * state)
|
||||
{
|
||||
|
||||
int i, x;
|
||||
@@ -380,12 +570,6 @@ void processM17(dsd_opts * opts, dsd_state * state)
|
||||
memset (m17_bits, 0, sizeof(m17_bits));
|
||||
memset (lich_bits, 0, sizeof(lich_bits));
|
||||
|
||||
|
||||
/*
|
||||
Within the Physical Layer, the 368 Type 4 bits are randomized and combined with the 16-bit
|
||||
Stream Sync Burst, which results in a complete frame of 384 bits (384 bits / 9600bps = 40 ms).
|
||||
*/
|
||||
|
||||
//load dibits into dibit buffer
|
||||
for (i = 0; i < 184; i++)
|
||||
dbuf[i] = (uint8_t) getDibit(opts, state);
|
||||
@@ -423,4 +607,140 @@ void processM17(dsd_opts * opts, dsd_state * state)
|
||||
//ending linebreak
|
||||
fprintf (stderr, "\n");
|
||||
|
||||
} //end processM17
|
||||
} //end processM17STR
|
||||
|
||||
void processM17LSF(dsd_opts * opts, dsd_state * state)
|
||||
{
|
||||
|
||||
//NOTE1: Pretty sure the flow here is all correct, but the initial (and only)
|
||||
//LSF frame is demodulated incorrectly, so more than likely, this frame will
|
||||
//always be bad since there is only one sent before STR
|
||||
|
||||
//NOTE2: Even with the preamble detection and LSF sync, we still get bad decode on this
|
||||
|
||||
int i, j, k, x;
|
||||
uint8_t dbuf[384]; //384-bit frame - 16-bit (8 symbol) sync pattern (184 dibits)
|
||||
uint8_t m17_rnd_bits[500]; //368 bits that are still scrambled (randomized)
|
||||
uint8_t m17_int_bits[500]; //368 bits that are still interleaved
|
||||
uint8_t m17_bits[500]; //368 bits that have been de-interleaved and de-scramble
|
||||
uint8_t m17_depunc[500]; //488 bits after depuncturing
|
||||
|
||||
memset (dbuf, 0, sizeof(dbuf));
|
||||
memset (m17_rnd_bits, 0, sizeof(m17_rnd_bits));
|
||||
memset (m17_int_bits, 0, sizeof(m17_int_bits));
|
||||
memset (m17_bits, 0, sizeof(m17_bits));
|
||||
memset (m17_depunc, 0, sizeof(m17_depunc));
|
||||
|
||||
//load dibits into dibit buffer
|
||||
for (i = 0; i < 184; i++)
|
||||
dbuf[i] = (uint8_t) getDibit(opts, state);
|
||||
|
||||
//convert dbuf into a bit array
|
||||
for (i = 0; i < 184; i++)
|
||||
{
|
||||
m17_rnd_bits[i*2+0] = (dbuf[i] >> 1) & 1;
|
||||
m17_rnd_bits[i*2+1] = (dbuf[i] >> 0) & 1;
|
||||
}
|
||||
|
||||
//descramble the frame
|
||||
for (i = 0; i < 368; i++)
|
||||
m17_int_bits[i] = (m17_rnd_bits[i] ^ m17_scramble[i]) & 1;
|
||||
|
||||
//deinterleave the bit array using Quadratic Permutation Polynomial
|
||||
//function π(x) = (45x + 92x^2 ) mod 368
|
||||
for (i = 0; i < 368; i++)
|
||||
{
|
||||
x = ((45*i)+(92*i*i)) % 368;
|
||||
m17_bits[i] = m17_int_bits[x];
|
||||
}
|
||||
|
||||
j = 0; k = 0; x = 0;
|
||||
|
||||
// P1 Depuncture
|
||||
for (i = 0; i < 488; i++)
|
||||
{
|
||||
if (p1[k++] == 1) m17_depunc[x++] = m17_bits[j++];
|
||||
else m17_depunc[x++] = 1;
|
||||
|
||||
if (k == 61) k = 0; //61 -- should reset 8 times againt the array
|
||||
|
||||
}
|
||||
|
||||
//debug -- values seem okay at end of run
|
||||
// fprintf (stderr, "K = %d; J = %d; X = %d", k, j, x);
|
||||
|
||||
//setup the convolutional decoder
|
||||
uint8_t temp[500];
|
||||
uint8_t s0;
|
||||
uint8_t s1;
|
||||
uint8_t m_data[32];
|
||||
uint8_t trellis_buf[400];
|
||||
memset (trellis_buf, 0, sizeof(trellis_buf));
|
||||
memset (temp, 0, sizeof (temp));
|
||||
memset (m_data, 0, sizeof (m_data));
|
||||
|
||||
for (i = 0; i < 488; i++)
|
||||
temp[i] = m17_depunc[i] << 1;
|
||||
|
||||
CNXDNConvolution_start();
|
||||
for (i = 0; i < 244; i++)
|
||||
{
|
||||
s0 = temp[(2*i)];
|
||||
s1 = temp[(2*i)+1];
|
||||
|
||||
CNXDNConvolution_decode(s0, s1);
|
||||
}
|
||||
|
||||
CNXDNConvolution_chainback(m_data, 240);
|
||||
|
||||
//244/8 = 30, last 4 (244-248) are trailing zeroes
|
||||
for(i = 0; i < 30; i++)
|
||||
{
|
||||
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
|
||||
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
|
||||
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
|
||||
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
|
||||
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
|
||||
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
|
||||
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
|
||||
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
|
||||
}
|
||||
|
||||
memset (state->m17_lsf, 0, sizeof(state->m17_lsf));
|
||||
memcpy (state->m17_lsf, trellis_buf, 240);
|
||||
|
||||
uint8_t lsf_packed[30];
|
||||
memset (lsf_packed, 0, sizeof(lsf_packed));
|
||||
|
||||
//need to pack bytes for the sw5wwp variant of the crc (might as well, may be useful in the future)
|
||||
for (i = 0; i < 30; i++)
|
||||
lsf_packed[i] = (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[i*8], 8);
|
||||
|
||||
uint16_t crc_cmp = crc16m17(lsf_packed, 28);
|
||||
uint16_t crc_ext = (uint16_t)ConvertBitIntoBytes(&state->m17_lsf[224], 16);
|
||||
int crc_err = 0;
|
||||
|
||||
if (crc_cmp != crc_ext) crc_err = 1;
|
||||
|
||||
if (crc_err == 0)
|
||||
M17decodeLSF(state);
|
||||
|
||||
if (opts->payload == 1)
|
||||
{
|
||||
fprintf (stderr, "\n LSF: ");
|
||||
for (i = 0; i < 30; i++)
|
||||
{
|
||||
if (i == 15) fprintf (stderr, "\n ");
|
||||
fprintf (stderr, "[%02X]", lsf_packed[i]);
|
||||
}
|
||||
}
|
||||
|
||||
//debug
|
||||
// fprintf (stderr, " E-%04X; C-%04X (CRC CHK)", crc_ext, crc_cmp);
|
||||
|
||||
if (crc_err == 1) fprintf (stderr, " CRC ERR");
|
||||
|
||||
//ending linebreak
|
||||
fprintf (stderr, "\n");
|
||||
|
||||
} //end processM17LSF
|
||||
|
||||
Reference in New Issue
Block a user