mordae/pico-sdr
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Fix gain, DC offset

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Jan Hamal Dvořák 2024-08-03 10:00:36 +02:00
parent 347582cfc1
commit 1fe4633601
2 changed files with 14 additions and 12 deletions
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2
grc/PicoSDR-WBFM.grc
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@ -374,7 +374,7 @@ blocks:
freq7: 100e6 freq7: 100e6
freq8: 100e6 freq8: 100e6
freq9: 100e6 freq9: 100e6
gain0: '0' gain0: '30'
gain1: '10' gain1: '10'
gain10: '10' gain10: '10'
gain11: '10' gain11: '10'

24
src/main.c
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@ -22,7 +22,7 @@
#include <stdlib.h> #include <stdlib.h>
#define VREG_VOLTAGE VREG_VOLTAGE_1_20 #define VREG_VOLTAGE VREG_VOLTAGE_1_20
#define CLK_SYS_HZ (288 * MHZ) #define CLK_SYS_HZ (300 * MHZ)
#define INIT_SAMPLE_RATE 200000 #define INIT_SAMPLE_RATE 200000
#define INIT_FREQ 94600000 #define INIT_FREQ 94600000
@ -559,11 +559,13 @@ inline static struct IQ next_sample()
I *= gain; I *= gain;
I /= 1024; I /= 1024;
I *= max_amplitude_mul; I *= max_amplitude_mul;
I += 127.4 * (1 << 16);
I /= (1 << 16); I /= (1 << 16);
Q *= gain; Q *= gain;
Q /= 1024; Q /= 1024;
Q *= max_amplitude_mul; Q *= max_amplitude_mul;
Q += 127.4 * (1 << 16);
Q /= (1 << 16); Q /= (1 << 16);
return (struct IQ){ I, Q }; return (struct IQ){ I, Q };
@ -586,19 +588,19 @@ static void rf_rx(void)
int64_t I = IQ.I; int64_t I = IQ.I;
int64_t Q = IQ.Q; int64_t Q = IQ.Q;
if (I > 127) if (I < 0)
I = 127; I = 0;
else if (I < -128) else if (I > 255)
I = -128; I = 255;
*blockptr++ = (uint8_t)I + 128; *blockptr++ = I;
if (Q > 127) if (Q < 0)
Q = 127; Q = 0;
else if (Q < -128) else if (Q > 255)
Q = -128; Q = 255;
*blockptr++ = (uint8_t)Q + 128; *blockptr++ = Q;
} }
if (queue_try_add(&iq_queue, &block)) { if (queue_try_add(&iq_queue, &block)) {