radio95/fm95
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Code Issues Activity

expose more settings to config and change bs412 compression logic

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This commit is contained in:
KubaPro010
2025-06-28 19:22:09 +02:00
parent 64424959ab
commit b6231bb345
2 changed files with 27 additions and 7 deletions
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6
README.md
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@@ -22,7 +22,7 @@ and one output:
## How to compile?
Note that you're required also to load submodules, if you don't know what that means then ask ChatGPT
Note that you're required also to load submodules, if you don't know what that means, ask ChatGPT
To compile you need `cmake`, `liquid-dsp` and `libpulse-dev`, if you have those then do these commands:
@@ -46,3 +46,7 @@ FM95 also includes some other apps, such as chimer95 which generates GTS tones e
## FM95 Calibration
FM95 features a calibration mode `-V` which instead of outputing the MPX just outputs a 400 hz tone, use that tone to match the deviation on your transmitter
## Usage of other projects
The apps use inih by Ben Hoyt.

28
src/fm95.c
View File

@@ -19,7 +19,6 @@
#include "../dsp/oscillator.h"
#include "../filter/iir.h"
#include "../modulation/fm_modulator.h"
#include "../modulation/stereo_encoder.h"
#include "../filter/bs412.h"
#include "../filter/gain_control.h"
@@ -70,6 +69,10 @@ typedef struct
uint8_t lpf_order;
float preemp_unity_freq;
float agc_target;
float agc_attack;
float agc_release;
float agc_max;
float agc_min;
} FM95_Config;
typedef struct
@@ -156,10 +159,11 @@ int run_fm95(const FM95_Config config, FM95_Runtime* runtime) {
init_stereo_encoder(&stencode, 4.0f, &osc, (config.stereo == 2), MONO_VOLUME, PILOT_VOLUME, STEREO_VOLUME);
float bs412_audio_gain = 1.0f;
float bs412_attack_alpha = expf(-1.0f / (0.03f * config.sample_rate));
float bs412_release_alpha = expf(-1.0f / (0.1f * config.sample_rate));
AGC agc;
// min max attack release
initAGC(&agc, config.sample_rate, config.agc_target, 0.1f, 2.75f, 0.03f, 0.225f);
initAGC(&agc, config.sample_rate, config.agc_target, config.agc_min, config.agc_max, config.agc_attack, config.agc_release);
int pulse_error;
@@ -225,9 +229,9 @@ int run_fm95(const FM95_Config config, FM95_Runtime* runtime) {
target_gain = fmaxf(target_gain, 0.1f);
target_gain = fminf(target_gain, 1.0f);
bs412_audio_gain = 0.8f * bs412_audio_gain + 0.2f * target_gain;
bs412_audio_gain = bs412_attack_alpha * bs412_audio_gain + (1 - bs412_attack_alpha) * target_gain;
}
} else bs412_audio_gain = fminf(1.0f, bs412_audio_gain + 0.001f);
} else bs412_audio_gain = bs412_release_alpha * bs412_audio_gain + (1 - bs412_release_alpha) * 1.0f;
mpx *= bs412_audio_gain;
@@ -324,6 +328,14 @@ static int config_handler(void* user, const char* section, const char* name, con
pconfig->sample_rate = atoi(value);
} else if(MATCH("advanced", "agc_target")) {
pconfig->agc_target = strtof(value, NULL);
} else if(MATCH("advanced", "agc_attack")) {
pconfig->agc_attack = strtof(value, NULL);
} else if(MATCH("advanced", "agc_release")) {
pconfig->agc_release = strtof(value, NULL);
} else if(MATCH("advanced", "agc_min")) {
pconfig->agc_min = strtof(value, NULL);
} else if(MATCH("advanced", "agc_max")) {
pconfig->agc_max = strtof(value, NULL);
} else {
return 0; // Unknown section/name
}
@@ -416,7 +428,11 @@ int main(int argc, char **argv) {
.lpf_order = 17,
.preemp_unity_freq = 15250.0f,
.agc_target = 0.625f
.agc_target = 0.625f,
.agc_attack = 0.03f,
.agc_release = 0.225f,
.agc_min = 0.1f,
.agc_max = 1.75f,
};
FM95_DeviceNames dv_names = {