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Tweaks to noise measurements.

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This commit is contained in:
Oliver Jowett 2015-06-16 10:13:25 +01:00
parent 7d4eaf6a48
commit 21bdc45bf0
7 changed files with 48 additions and 50 deletions
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56
demod_2400.c
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@ -161,7 +161,7 @@ void demodulate2400(struct mag_buf *mag)
uint16_t *m = mag->data;
uint32_t mlen = mag->length;
double total_signal_power = 0.0;
uint64_t sum_scaled_signal_power = 0;
memset(&mm, 0, sizeof(mm));
msg = msg1;
@ -412,30 +412,6 @@ void demodulate2400(struct mag_buf *mag)
mm.score = bestscore;
mm.bFlags = mm.correctedbits = 0;
// measure signal power
{
uint64_t signal_power_sum = 0;
double signal_power;
int signal_len = msglen*12/5 + 1;
int k;
for (k = 0; k < signal_len; ++k) {
uint64_t s = m[j+19+k];
signal_power_sum += s * s;
}
mm.signalLevel = signal_power = signal_power_sum / MAX_POWER / signal_len;
Modes.stats_current.signal_power_sum += signal_power;
Modes.stats_current.signal_power_count ++;
if (signal_power > Modes.stats_current.peak_signal_power)
Modes.stats_current.peak_signal_power = signal_power;
if (signal_power > 0.50119)
Modes.stats_current.strong_signal_count++; // signal power above -3dBFS
total_signal_power += signal_power_sum / MAX_POWER;
}
// Decode the received message
{
int result = decodeModesMessage(&mm, bestmsg);
@ -450,6 +426,29 @@ void demodulate2400(struct mag_buf *mag)
}
}
// measure signal power
{
double signal_power;
uint64_t scaled_signal_power = 0;
int signal_len = msglen*12/5;
int k;
for (k = 0; k < signal_len; ++k) {
uint32_t mag = m[j+19+k];
scaled_signal_power += mag * mag;
}
signal_power = scaled_signal_power / 65535.0 / 65535.0;
mm.signalLevel = signal_power / signal_len;
Modes.stats_current.signal_power_sum += signal_power;
Modes.stats_current.signal_power_count += signal_len;
sum_scaled_signal_power += scaled_signal_power;
if (mm.signalLevel > Modes.stats_current.peak_signal_power)
Modes.stats_current.peak_signal_power = mm.signalLevel;
if (mm.signalLevel > 0.50119)
Modes.stats_current.strong_signal_count++; // signal power above -3dBFS
}
// Skip over the message:
// (we actually skip to 8 bits before the end of the message,
@ -457,7 +456,7 @@ void demodulate2400(struct mag_buf *mag)
// where the preamble of the second message clobbered the last
// few bits of the first message, but the message bits didn't
// overlap)
j += (8 + msglen - 8)*12/5 - 1;
j += msglen*12/5;
// Pass data to the next layer
useModesMessage(&mm);
@ -465,8 +464,9 @@ void demodulate2400(struct mag_buf *mag)
/* update noise power if measured */
if (Modes.measure_noise) {
Modes.stats_current.noise_power_sum += (mag->total_power - total_signal_power) / mag->length;
Modes.stats_current.noise_power_count ++;
double sum_signal_power = sum_scaled_signal_power / 65535.0 / 65535.0;
Modes.stats_current.noise_power_sum += (mag->total_power - sum_signal_power);
Modes.stats_current.noise_power_count += mag->length;
}
}