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added demod_or_erase() helper function

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This commit is contained in:
Ahmet Inan 2021-08-29 17:42:20 +02:00
commit 3665d495b7
1 changed files with 23 additions and 14 deletions
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37
decode.cc
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@ -58,6 +58,15 @@ struct SchmidlCox
{
return (carrier + symbol_len) % symbol_len;
}
static cmplx demod_or_erase(cmplx curr, cmplx prev)
{
if (!(norm(prev) > 0))
return 0;
cmplx cons = curr / prev;
if (!(norm(cons) <= 4))
return 0;
return cons;
}
public:
int symbol_pos = 0;
value cfo_rad = 0;
@ -108,12 +117,7 @@ public:
tmp1[i] = samples[i+symbol_pos+symbol_len] * osc();
fwd(tmp0, tmp1);
for (int i = 0; i < symbol_len; ++i)
tmp1[i] = 0;
for (int i = 0; i < symbol_len; ++i)
if (norm(tmp0[bin(i-1)]) > 0 &&
std::min(norm(tmp0[i]), norm(tmp0[bin(i-1)])) * 2 >
std::max(norm(tmp0[i]), norm(tmp0[bin(i-1)])))
tmp1[i] = tmp0[i] / tmp0[bin(i-1)];
tmp1[i] = demod_or_erase(tmp0[i], tmp0[bin(i-1)]);
fwd(tmp0, tmp1);
for (int i = 0; i < symbol_len; ++i)
tmp0[i] *= kern[i];
@ -209,6 +213,15 @@ struct Decoder
{
return 1 - 2 * bit;
}
static cmplx demod_or_erase(cmplx curr, cmplx prev)
{
if (!(norm(prev) > 0))
return 0;
cmplx cons = curr / prev;
if (!(norm(cons) <= 4))
return 0;
return cons;
}
const cmplx *mls0_seq()
{
CODE::MLS seq0(mls0_poly);
@ -333,8 +346,9 @@ struct Decoder
uint8_t data[(mls1_len+7)/8];
for (int i = 0; i < mls1_len; ++i)
soft[i] = std::min<value>(std::max<value>(
std::nearbyint(127 * (fdom[bin(i+mls1_off)] /
fdom[bin(i-1+mls1_off)]).real()), -128), 127);
std::nearbyint(127 * demod_or_erase(
fdom[bin(i+mls1_off)], fdom[bin(i-1+mls1_off)]).real()),
-128), 127);
bool unique = osddec(data, soft, genmat);
if (!unique) {
std::cerr << "OSD error." << std::endl;
@ -414,12 +428,7 @@ struct Decoder
head[bin(i+code_off)] = fdom[bin(i+code_off)];
fwd(fdom, cur += symbol_len+guard_len);
for (int i = 0; i < code_cols; ++i)
cons[code_cols*j+i] = fdom[bin(i+code_off)] / head[bin(i+code_off)];
}
if (1) {
for (int i = 0; i < cons_cnt; ++i)
if (norm(cons[i]) > 4)
cons[i] = 0;
cons[code_cols*j+i] = demod_or_erase(fdom[bin(i+code_off)], head[bin(i+code_off)]);
}
if (1) {
value sum = 0;