From b335dcdea66ca844d88a8b03ed87a37ff6268cc7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Hamal=20Dvo=C5=99=C3=A1k?= <mordae@anilinux.org>
Date: Sat, 27 Jan 2024 13:55:27 +0100
Subject: [PATCH] Enable higher bit depths
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>
---
src/main.c | 44 +++++++++++++++++++++-----------------------
1 file changed, 21 insertions(+), 23 deletions(-)
diff --git a/src/main.c b/src/main.c
index 5c6fa6d..a974051 100644
--- a/src/main.c
+++ b/src/main.c
@@ -62,8 +62,8 @@ static int rx_dma = -1;
static volatile struct status {
unsigned mtime;
- unsigned rssi_raw;
- unsigned rssi_max;
+ float rssi_raw;
+ float rssi_max;
unsigned sample_rate;
int frequency;
int angle;
@@ -368,12 +368,12 @@ static __unused bool is_prime_or_one(int n)
static void rf_rx(void)
{
- unsigned assi0 = 0, assi1 = 0, assi2 = 0;
+ uint64_t assi0 = 0, assi1 = 0, assi2 = 0;
- status.rssi_max = pow(2.0f * 0.707f * 127.0f * (1 << EXTRA_BITS), 2.0f);
+ status.rssi_max = 0.5f * powf(127.5f * (1 << EXTRA_BITS), 2.0f);
#if HPF_ALPHA
- int hpI = 0, hpQ = 0;
+ int64_t hpI = 0, hpQ = 0;
#endif
#if LPF_SAMPLES
@@ -549,27 +549,25 @@ static void rf_rx(void)
I -= 16 * NUM_SAMPLES;
Q -= 16 * NUM_SAMPLES;
-#if EXTRA_BITS
+#if SPEED == 3
+ /* Normalize to given number of bits. */
+ I = (I * ((1 << (7 + EXTRA_BITS)) - 1)) / 16;
+ Q = (Q * ((1 << (7 + EXTRA_BITS)) - 1)) / 16;
+#else
I <<= EXTRA_BITS;
Q <<= EXTRA_BITS;
#endif
-
-#if SPEED == 3
- /* Normalize to 8 bits. */
- I = (I * 127) / 16;
- Q = (Q * 127) / 16;
-#endif
I /= NUM_SAMPLES;
Q /= NUM_SAMPLES;
#if HPF_ALPHA
- int tmpI = I * 256;
- I -= hpI / 256;
- hpI = (hpI * ((1 << 10) - HPF_ALPHA) + tmpI * HPF_ALPHA) >> 10;
+ int64_t tmpI = (int64_t)I << 16;
+ I -= hpI >> 16;
+ hpI = (hpI * ((1 << 16) - HPF_ALPHA) + tmpI * HPF_ALPHA) >> 16;
- int tmpQ = Q * 256;
- Q -= hpQ / 256;
- hpQ = (hpQ * ((1 << 10) - HPF_ALPHA) + tmpQ * HPF_ALPHA) >> 10;
+ int64_t tmpQ = (int64_t)Q << 16;
+ Q -= hpQ >> 16;
+ hpQ = (hpQ * ((1 << 16) - HPF_ALPHA) + tmpQ * HPF_ALPHA) >> 16;
#endif
#if LPF_SAMPLES
@@ -631,14 +629,14 @@ static void rf_rx(void)
angle_stride++;
}
- unsigned ssi = I * I + Q * Q;
- const unsigned alpha = RSSI_ALPHA;
+ uint64_t ssi = (uint64_t)I * (uint64_t)I + (uint64_t)Q * (uint64_t)Q;
+ const uint64_t alpha = RSSI_ALPHA;
- assi0 = (assi0 * (256 - alpha) + ssi * 16 * alpha) / 256;
+ assi0 = (assi0 * (256 - alpha) + (ssi << 16) * alpha) / 256;
assi1 = (assi1 * (256 - alpha) + assi0 * alpha) / 256;
assi2 = (assi2 * (256 - alpha) + assi1 * alpha) / 256;
- status.rssi_raw = assi2 / 16;
+ status.rssi_raw = assi2 >> 16;
status.frequency = frequency;
status.sample_rate = CLK_SYS_HZ / (delta_netto * 32);
status.angle = rotation << 16;
@@ -762,7 +760,7 @@ static void command(const char *cmd)
last = st.mtime;
- float rssi_rel = (float)st.rssi_raw / (float)st.rssi_max;
+ float rssi_rel = st.rssi_raw / st.rssi_max;
printf("%5.1f dB (%4u) [%5u %+7i] %+5.1f ", 10.0f * log10f(rssi_rel),
(unsigned)sqrt(st.rssi_raw), st.sample_rate,