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we already are oversampled

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This commit is contained in:
Ahmet Inan 2023-12-14 08:51:25 +01:00
commit 0cf139ddaf
1 changed files with 15 additions and 28 deletions
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45
encode.cc
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@ -41,16 +41,15 @@ struct Encoder
static const int mls1_poly = 0b100101011;
static const int mls2_poly = 0b100101010001;
DSP::WritePCM<value> *pcm;
DSP::FastFourierTransform<symbol_len, cmplx, -1> fwd;
DSP::FastFourierTransform<symbol_len, cmplx, 1> bwd;
DSP::FastFourierTransform<4*symbol_len, cmplx, -1> fwd4;
DSP::FastFourierTransform<4*symbol_len, cmplx, 1> bwd4;
CODE::CRC<uint16_t> crc0;
CODE::CRC<uint32_t> crc1;
CODE::BoseChaudhuriHocquenghemEncoder<255, 71> bchenc;
CODE::PolarSysEnc<code_type> polarenc;
code_type code[code_len], mesg[max_bits];
cmplx fdom[symbol_len], fdom4[4*symbol_len];
cmplx tdom[symbol_len], tdom4[4*symbol_len];
cmplx fdom[symbol_len];
cmplx tdom[symbol_len];
cmplx temp[symbol_len];
cmplx guard[guard_len];
cmplx papr_min, papr_max;
@ -62,44 +61,32 @@ struct Encoder
{
return (carrier + symbol_len) % symbol_len;
}
static int bin4(int carrier)
{
return (carrier + 4*symbol_len) % (4*symbol_len);
}
static int nrz(bool bit)
{
return 1 - 2 * bit;
}
void improve_papr()
{
for (int i = 0; i < 4*symbol_len; ++i)
fdom4[i] = 0;
for (int i = -symbol_len/2; i < symbol_len/2; ++i)
fdom4[bin4(i)] = fdom[bin(i)];
bwd4(tdom4, fdom4);
for (int i = 0; i < 4*symbol_len; ++i)
tdom4[i] /= std::sqrt(value(4*symbol_len));
for (int i = 0; i < 4*symbol_len; ++i) {
value amp = std::max(std::abs(tdom4[i].real()), std::abs(tdom4[i].imag()));
if (amp > value(1))
tdom4[i] /= amp;
for (int i = 0; i < symbol_len; ++i) {
value pwr = norm(tdom[i]);
if (pwr > value(1))
tdom[i] /= sqrt(pwr);
}
fwd4(fdom4, tdom4);
for (int i = -symbol_len/2; i < symbol_len/2; ++i)
if (norm(temp[bin(i)]))
temp[bin(i)] = fdom4[bin4(i)] / std::sqrt(value(4*symbol_len));
fwd(temp, tdom);
for (int i = 0; i < symbol_len; ++i)
if (norm(fdom[i]))
temp[i] /= symbol_len;
else
temp[bin(i)] = 0;
temp[i] = 0;
bwd(tdom, temp);
}
void symbol(bool papr_reduction = true)
{
for (int i = 0; i < symbol_len; ++i)
temp[i] = fdom[i];
if (papr_reduction)
improve_papr();
bwd(tdom, temp);
bwd(tdom, fdom);
for (int i = 0; i < symbol_len; ++i)
tdom[i] /= std::sqrt(value(8*symbol_len));
if (papr_reduction)
improve_papr();
for (int i = 0; i < guard_len; ++i) {
value x = value(i) / value(guard_len - 1);
value ratio(0.5);