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sdrangel/plugins/channelrx/demoddatv/leansdr/sdr.cpp

123 lines
3.2 KiB
C++

///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019, 2021 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////////
#include "sdr.h"
namespace leansdr
{
const char *cstln_base::names[] =
{
"BPSK",
"QPSK",
"8PSK",
"16APSK",
"32APSK",
"64APSKe",
"16QAM",
"64QAM",
"256QAM"
};
void softsymb_harden(llr_ss *ss)
{
for (int b = 0; b < 8; ++b) {
ss->bits[b] = (ss->bits[b] < 0) ? -127 : 127;
}
}
void softsymb_harden(hard_ss *ss)
{
(void)ss; // NOP
}
void softsymb_harden(eucl_ss *ss)
{
for (int s = 0; s < ss->MAX_SYMBOLS; ++s) {
ss->dists2[s] = (s == ss->nearest) ? 0 : 1;
}
}
uint8_t softsymb_to_dump(const llr_ss &ss, int bit)
{
return 128 - ss.bits[bit];
}
uint8_t softsymb_to_dump(const hard_ss &ss, int bit)
{
return ((ss >> bit) & 1) ? 255 : 0;
}
uint8_t softsymb_to_dump(const eucl_ss &ss, int bit)
{
(void)bit;
return ss.dists2[ss.nearest] >> 8;
}
void to_softsymb(const full_ss *fss, hard_ss *ss)
{
*ss = fss->nearest;
}
void to_softsymb(const full_ss *fss, eucl_ss *ss)
{
for (int s = 0; s < ss->MAX_SYMBOLS; ++s) {
ss->dists2[s] = fss->dists2[s];
}
uint16_t best = 65535, best2 = 65535;
for (int s = 0; s < ss->MAX_SYMBOLS; ++s)
{
if (fss->dists2[s] < best)
{
best2 = best;
best = fss->dists2[s];
}
else if (fss->dists2[s] < best2)
{
best2 = fss->dists2[s];
}
}
ss->discr2 = best2 - best;
ss->nearest = fss->nearest;
}
void to_softsymb(const full_ss *fss, llr_ss *ss)
{
for (int b = 0; b < 8; ++b)
{
float v = (1.0f - fss->p[b]) / (fss->p[b] + 1e-6);
int r = logf(v) * 5; // TBD Optimal scaling vs saturation ?
if (r < -127) {
r = -127;
}
if (r > 127) {
r = 127;
}
ss->bits[b] = r;
}
}
} // leansdr