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compute the complex PAPR

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even though we only use the real part
This commit is contained in:
Ahmet Inan 2023-12-14 09:14:58 +01:00
commit b2c0e56c4f
1 changed files with 11 additions and 13 deletions
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24
encode.cc
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@ -52,7 +52,7 @@ struct Encoder
cmplx tdom[symbol_len];
cmplx temp[symbol_len];
cmplx guard[guard_len];
cmplx papr_min, papr_max;
value papr_min, papr_max;
int code_off;
int mls0_off;
int mls1_off;
@ -94,17 +94,17 @@ struct Encoder
x = value(0.5) * (value(1) - std::cos(DSP::Const<value>::Pi() * x));
guard[i] = DSP::lerp(guard[i], tdom[i+symbol_len-guard_len], x);
}
cmplx peak, mean;
value peak = 0, mean = 0;
for (int i = 0; i < symbol_len; ++i) {
cmplx power(tdom[i].real() * tdom[i].real(), tdom[i].imag() * tdom[i].imag());
peak = cmplx(std::max(peak.real(), power.real()), std::max(peak.imag(), power.imag()));
value power(norm(tdom[i]));
peak = std::max(peak, power);
mean += power;
}
if (mean.real() > 0 && mean.imag() > 0) {
cmplx papr(peak.real() / mean.real(), peak.imag() / mean.imag());
papr *= value(symbol_len);
papr_min = cmplx(std::min(papr_min.real(), papr.real()), std::min(papr_min.imag(), papr.imag()));
papr_max = cmplx(std::max(papr_max.real(), papr.real()), std::max(papr_max.imag(), papr.imag()));
mean /= symbol_len;
if (mean > 0) {
value papr(peak / mean);
papr_min = std::min(papr_min, papr);
papr_max = std::max(papr_max, papr);
}
pcm->write(reinterpret_cast<value *>(guard), guard_len, 2);
pcm->write(reinterpret_cast<value *>(tdom), symbol_len, 2);
@ -176,7 +176,7 @@ struct Encoder
code_off = offset - cons_cols / 2;
mls0_off = offset - mls0_len + 1;
mls1_off = offset - mls1_len / 2;
papr_min = cmplx(1000, 1000), papr_max = cmplx(-1000, -1000);
papr_min = 1000, papr_max = -1000;
pilot_block();
schmidl_cox();
meta_data((call_sign << 8) | oper_mode);
@ -217,9 +217,7 @@ struct Encoder
for (int i = 0; i < symbol_len; ++i)
fdom[i] = 0;
symbol();
std::cerr << "real PAPR: " << DSP::decibel(papr_min.real()) << " .. " << DSP::decibel(papr_max.real()) << " dB" << std::endl;
if (pcm->channels() == 2)
std::cerr << "imag PAPR: " << DSP::decibel(papr_min.imag()) << " .. " << DSP::decibel(papr_max.imag()) << " dB" << std::endl;
std::cerr << "PAPR: " << DSP::decibel(papr_min) << " .. " << DSP::decibel(papr_max) << " dB" << std::endl;
}
};