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made offsets accessible to other methods

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This commit is contained in:
Ahmet Inan 2025-07-02 07:05:20 +02:00
commit 69ebf0ea29
2 changed files with 27 additions and 23 deletions
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28
decode.cc
View file

@ -56,8 +56,8 @@ struct Decoder
static const int data_tones = 256;
static const int block_length = 10;
static const int block_skew = 3;
static const int pilot_offset = 4;
static const int reserved_offset = 9;
static const int first_pilot = 4;
static const int first_reserved = 9;
static const int tone_count = data_tones + pilot_tones + reserved_tones;
static const int tone_off = - tone_count / 2;
static const int tones_max = tone_count * symbols_max;
@ -87,6 +87,8 @@ struct Decoder
int crc_bits;
int data_bits;
int data_bytes;
int pilot_off;
int reserved_off;
int symbol_count;
static int bin(int carrier)
@ -321,7 +323,7 @@ struct Decoder
CODE::MLS seq1(mls1_poly);
auto clamp = [](int v){ return v < -127 ? -127 : v > 127 ? 127 : v; };
for (int i = 0; i < pilot_tones; ++i)
mode[i] = clamp(std::nearbyint(127 * demod_or_erase(tone[i*block_length+pilot_offset], chan[i*block_length+pilot_offset]).real() * nrz(seq1())));
mode[i] = clamp(std::nearbyint(127 * demod_or_erase(tone[i*block_length+first_pilot], chan[i*block_length+first_pilot]).real() * nrz(seq1())));
int oper_mode = hadamarddec(mode);
if (oper_mode < 0 || oper_mode > 15) {
std::cerr << "operation mode " << oper_mode << " unsupported." << std::endl;
@ -349,14 +351,14 @@ struct Decoder
seq1.reset();
hadamardenc(mode, oper_mode);
}
int poff = (block_skew * j + pilot_offset) % block_length;
pilot_off = (block_skew * j + first_pilot) % block_length;
for (int i = 0; i < pilot_tones; ++i)
tone[block_length*i+poff] *= nrz(seq1()) * mode[i];
tone[block_length*i+pilot_off] *= nrz(seq1()) * mode[i];
for (int i = 0; i < tone_count; ++i)
demod[tone_count*j+i] = demod_or_erase(tone[i], chan[i]);
for (int i = 0; i < pilot_tones; ++i) {
index[i] = tone_off + block_length * i + poff;
phase[i] = arg(demod[tone_count*j+block_length*i+poff]);
index[i] = tone_off + block_length * i + pilot_off;
phase[i] = arg(demod[tone_count*j+block_length*i+pilot_off]);
}
tse.compute(index, phase, pilot_tones);
//std::cerr << "Theil-Sen slope = " << tse.slope() << std::endl;
@ -364,7 +366,7 @@ struct Decoder
for (int i = 0; i < tone_count; ++i)
demod[tone_count*j+i] *= DSP::polar<value>(1, -tse(i+tone_off));
for (int i = 0; i < tone_count; ++i)
if (i % block_length == poff)
if (i % block_length == pilot_off)
chan[i] = tone[i];
else
chan[i] *= DSP::polar<value>(1, tse(i+tone_off));
@ -374,11 +376,11 @@ struct Decoder
std::cerr << "Es/N0 (dB):";
value sp = 0, np = 0;
for (int j = 0, k = 0; j < symbol_count; ++j) {
int poff = (block_skew * j + pilot_offset) % block_length;
int roff = (block_skew * j + reserved_offset) % block_length;
pilot_off = (block_skew * j + first_pilot) % block_length;
reserved_off = (block_skew * j + first_reserved) % block_length;
for (int i = 0; i < pilot_tones; ++i) {
cmplx hard(1, 0);
cmplx error = demod[tone_count*j+block_length*i+poff] - hard;
cmplx error = demod[tone_count*j+block_length*i+pilot_off] - hard;
sp += norm(hard);
np += norm(error);
}
@ -386,9 +388,9 @@ struct Decoder
value snr = DSP::decibel(precision);
std::cerr << " " << snr;
for (int i = 0; i < tone_count; ++i) {
if (i % block_length == poff)
if (i % block_length == pilot_off)
continue;
if (i % block_length == roff)
if (i % block_length == reserved_off)
continue;
int bits = mod_bits;
if (oper_mode >= 9 && oper_mode <= 11 && k % 64 == 60)

22
encode.cc
View file

@ -40,8 +40,8 @@ struct Encoder
static const int tone_count = data_tones + pilot_tones + reserved_tones;
static const int block_length = 10;
static const int block_skew = 3;
static const int pilot_offset = 4;
static const int reserved_offset = 9;
static const int first_pilot = 4;
static const int first_reserved = 9;
DSP::WritePCM<value> *pcm;
DSP::FastFourierTransform<symbol_len, cmplx, -1> fwd;
DSP::FastFourierTransform<symbol_len, cmplx, 1> bwd;
@ -65,6 +65,8 @@ struct Encoder
int data_bytes;
int code_order;
int tone_off;
int pilot_off;
int reserved_off;
int symbol_count;
static int bin(int carrier)
@ -344,13 +346,13 @@ struct Encoder
int offset = (freq_off * symbol_len) / rate;
tone_off = offset - tone_count / 2;
}
void tone_reservation_kernel(int roff)
void tone_reservation_kernel()
{
value mag = 1 / value(10 * reserved_tones);
for (int i = 0; i < symbol_len; ++i)
temp[i] = 0;
for (int i = 0; i < reserved_tones; ++i)
temp[bin(i*block_length+tone_off+roff)] = mag;
temp[bin(i*block_length+tone_off+reserved_off)] = mag;
bwd(kern, temp);
}
void guard_interval_weights()
@ -376,7 +378,7 @@ struct Encoder
schmidl_cox();
CODE::MLS seq1(mls1_poly);
for (int i = 0, m = 0; i < tone_count; ++i) {
if (i % block_length == pilot_offset) {
if (i % block_length == first_pilot) {
tone[i] = nrz(seq1()) * mode[m++];
} else {
tone[i] = 0;
@ -410,12 +412,12 @@ struct Encoder
shuffle(perm, code);
CODE::MLS seq1(mls1_poly);
for (int j = 0, k = 0; j < symbol_count; ++j) {
int poff = (block_skew * j + pilot_offset) % block_length;
int roff = (block_skew * j + reserved_offset) % block_length;
pilot_off = (block_skew * j + first_pilot) % block_length;
reserved_off = (block_skew * j + first_reserved) % block_length;
for (int i = 0, m = 0; i < tone_count; ++i) {
if (i % block_length == poff) {
if (i % block_length == pilot_off) {
tone[i] = nrz(seq1()) * mode[m++];
} else if (i % block_length == roff) {
} else if (i % block_length == reserved_off) {
tone[i] = 0;
} else {
int bits = mod_bits;
@ -425,7 +427,7 @@ struct Encoder
k += bits;
}
}
tone_reservation_kernel(roff);
tone_reservation_kernel();
symbol();
}
}