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FT4 deomod: fixes

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f4exb 2026-03-08 21:40:07 +01:00
parent 76121cf789
commit c42f4a04cb
2 changed files with 15 additions and 11 deletions
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21
ft8/ft4.cpp
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@ -267,7 +267,7 @@ std::vector<Strength> FT4::coarse(const FFTEngine::ffts_t &bins, int si0, int si
float s = one_coarse_strength(bins, bi, si);
Strength st;
st.strength_ = s;
st.hz_ = bi * 20.833;
st.hz_ = bi * bin_hz;
st.off_ = si * block;
sv.push_back(st);
}
@ -599,7 +599,7 @@ void FT4::go(int npasses)
for (int hz_frac_i = 0; hz_frac_i < params.coarse_hz_n; hz_frac_i++)
{
// shift down by hz_frac
float hz_frac = hz_frac_i * (20.833 / params.coarse_hz_n);
float hz_frac = hz_frac_i * ((rate_ / (float)block) / params.coarse_hz_n);
std::vector<float> samples1;
if (hz_frac_i == 0) {
@ -742,7 +742,8 @@ float FT4::one_strength_known(
{
int block = blocksize(rate);
// assert(syms.size() == 103);
int bin0 = round(hz / 20.833);
float bin_hz = rate / (float)block;
int bin0 = round(hz / bin_hz);
float sig = 0;
float noise = 0;
float sum7 = 0;
@ -861,12 +862,14 @@ int FT4::search_time_fine_known(
off0 = 0;
}
int block = blocksize(rate);
float bin_hz = rate / (float)block;
// nearest FFT bin center.
float hz0 = round(hz / 20.833) * 20.833;
float hz0 = round(hz / bin_hz) * bin_hz;
// move hz to hz0, so it is centered in a symbol-sized bin.
std::vector<float> downsamples = fft_shift_f(bins, rate, hz - hz0);
int best_off = -1;
int block = blocksize(rate);
float best_sum = 0.0;
for (int g = off0; g <= offN; g += gran)
@ -2913,7 +2916,7 @@ float FT4::guess_snr(const FFTEngine::ffts_t &m103)
raw = 0.1;
}
raw /= (2500.0 / 12.0); // 9.0 hz noise b/w -> 2500 hz b/w (FT4: 3.33x wider than FT8's 2.7 Hz) + adjust
raw /= (2500.0 / 9.0); // 9.0 hz noise b/w -> 2500 hz b/w (FT4: 3.33x wider than FT8's 2.7 Hz)
float snr = 10 * log10(raw);
snr += 5;
snr *= 1.4;
@ -3444,7 +3447,7 @@ void FT4::subtract(
int sym = bin0 + re103[0];
float phase = phases[0];
float amp = amps[0];
float hz = 20.833 * sym;
float hz = sym * bin_hz;
float dtheta = 2 * M_PI / (rate_ / hz); // advance per sample
for (int jj = 0; jj < ramp; jj++)
@ -3462,7 +3465,7 @@ void FT4::subtract(
int sym = bin0 + re103[si];
float phase = phases[si];
float amp = amps[si];
float hz = 20.833 * sym;
float hz = sym * bin_hz;
float dtheta = 2 * M_PI / (rate_ / hz); // advance per sample
// we've already done the first ramp for this symbol.
@ -3495,7 +3498,7 @@ void FT4::subtract(
else
{
int sym1 = bin0 + re103[si + 1];
hz1 = 20.833 * sym1;
hz1 = sym1 * bin_hz;
phase1 = phases[si + 1];
}

5
sdrbench/test_ft4.cpp
View File

@ -246,9 +246,9 @@ void MainBench::testFT4(const QString& wavFile, const QString& argsStr)
qDebug("MainBench::testFT4: %s", qPrintable(QString::fromStdString(msg.first)));
}
if (msgMap.size() != 6)
if (msgMap.size() != 7)
{
qDebug("MainBench::testFT4: failed: invalid size: %lu expected 6", msgMap.size());
qDebug("MainBench::testFT4: failed: invalid size: %lu expected 7", msgMap.size());
return;
}
@ -258,6 +258,7 @@ void MainBench::testFT4(const QString& wavFile, const QString& argsStr)
"CQ PA8DC JO21",
"CQ R3YBG KO73",
"CQ YU7ZZ KN05",
"II3WOG GI0WHI IO74",
"W4WWQ 9A6T -11"
};