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added three new, non-differential modes

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This commit is contained in:
Ahmet Inan 2023-12-15 17:54:54 +01:00
commit d1a2ec19f0
2 changed files with 23 additions and 21 deletions
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28
decode.cc
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@ -189,6 +189,7 @@ struct Decoder
static const int mls1_len = 255;
static const int mls1_off = - mls1_len / 2;
static const int mls1_poly = 0b100101011;
static const int mls2_poly = 0b100101010001;
static const int buffer_len = 4 * extended_len;
static const int search_pos = extended_len;
DSP::ReadPCM<value> *pcm;
@ -206,7 +207,7 @@ struct Decoder
int8_t genmat[255*71];
mesg_type mesg[max_bits], mess[code_len];
code_type code[code_len];
cmplx cons[cons_total], prev[cons_cols];
cmplx cons[cons_total], chan[cons_cols];
cmplx fdom[symbol_len], tdom[symbol_len];
value index[cons_cols], phase[cons_cols];
value cfo_rad, sfo_rad;
@ -219,15 +220,15 @@ struct Decoder
{
return (carrier + symbol_len) % symbol_len;
}
static int nrz(bool bit)
static value nrz(bool bit)
{
return 1 - 2 * bit;
}
static cmplx demod_or_erase(cmplx curr, cmplx prev)
static cmplx demod_or_erase(cmplx curr, cmplx chan)
{
if (!(norm(prev) > 0))
if (!(norm(chan) > 0))
return 0;
cmplx cons = curr / prev;
cmplx cons = curr / chan;
if (!(norm(cons) <= 4))
return 0;
return cons;
@ -328,7 +329,7 @@ struct Decoder
continue;
}
oper_mode = md & 255;
if (oper_mode && (oper_mode < 14 || oper_mode > 16)) {
if (oper_mode && (oper_mode < 17 || oper_mode > 19)) {
std::cerr << "operation mode " << oper_mode << " unsupported." << std::endl;
continue;
}
@ -348,15 +349,16 @@ struct Decoder
if (!okay || !oper_mode)
return;
for (int i = 0; i < symbol_pos+extended_len; ++i)
for (int i = 0; i < symbol_pos+2*extended_len; ++i)
buf = next_sample();
for (int i = 0; i < symbol_len; ++i)
tdom[i] = buf[i] * osc();
for (int i = 0; i < guard_len; ++i)
osc();
fwd(fdom, tdom);
CODE::MLS seq2(mls2_poly);
for (int i = 0; i < cons_cols; ++i)
prev[i] = fdom[bin(i+code_off)];
chan[i] = nrz(seq2()) * fdom[bin(i+code_off)];
std::cerr << "demod ";
for (int j = 0; j < cons_rows; ++j) {
for (int i = 0; i < extended_len; ++i)
@ -367,9 +369,7 @@ struct Decoder
osc();
fwd(fdom, tdom);
for (int i = 0; i < cons_cols; ++i)
cons[cons_cols*j+i] = demod_or_erase(fdom[bin(i+code_off)], prev[i]);
for (int i = 0; i < cons_cols; ++i)
prev[i] = fdom[bin(i+code_off)];
cons[cons_cols*j+i] = demod_or_erase(fdom[bin(i+code_off)], chan[i]);
std::cerr << ".";
}
std::cerr << " done" << std::endl;
@ -425,15 +425,15 @@ struct Decoder
}
int data_bits = 0;
switch (oper_mode) {
case 14:
case 17:
data_bits = 1360;
frozen_bits = frozen_2048_1392;
break;
case 15:
case 18:
data_bits = 1024;
frozen_bits = frozen_2048_1056;
break;
case 16:
case 19:
data_bits = 680;
frozen_bits = frozen_2048_712;
break;