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Implements ALC and balances power in different modes #412

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39a80d4
further alc development
rkayakr Mar 4, 2026
7b38926
balance
rkayakr Mar 4, 2026
6ebe4ff
Revert "balance"
rkayakr Mar 4, 2026
51503cb
added balance, changed ssb_val to balance ssb only
rkayakr Mar 4, 2026
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2 changes: 1 addition & 1 deletion src/calibration_ui.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@
struct power_settings {
int f_start;
int f_stop;
int max_watts;
float max_watts;
double scale;
};

Expand Down
188 changes: 120 additions & 68 deletions src/sbitx.c
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Original file line number Diff line number Diff line change
@@ -1,4 +1,3 @@

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
Expand Down Expand Up @@ -51,9 +50,13 @@ FILE *pf_debug = NULL;
#define SBITX_V2 (1)

int sbitx_version = SBITX_V2;
int fwdpower, vswr;
int fwdpower_calc;
int fwdpower_cnt;
int fwdpower = 0;
float watts = 0.0;
float fwdvoltage = 0.0;
float vrms = 0.0;
int vswr = 0;
int cur_band;


float fft_bins[MAX_BINS]; // spectrum ampltiudes
float spectrum_window[MAX_BINS];
Expand All @@ -64,6 +67,13 @@ fftw_plan plan_spectrum;
void set_rx1(int frequency);
void tr_switch(int tx_on);

static inline uint64_t now_ns(void) {
struct timespec ts;
// Prefer RAW if supported; otherwise use CLOCK_MONOTONIC.
clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
return (uint64_t)ts.tv_sec * 1000000000ull + (uint64_t)ts.tv_nsec;
}

// Wisdom Defines for the FFTW and FFTWF libraries
// Options for WISDOM_MODE from least to most rigorous are FFTW_ESTIMATE, FFTW_MEASURE, FFTW_PATIENT, and FFTW_EXHAUSTIVE
// The FFTW_ESTIMATE mode seems to make completely incorrect Wisdom plan choices sometimes, and is not recommended.
Expand Down Expand Up @@ -105,8 +115,10 @@ static int tr_relay = 0;
static int rx_pitch = 700; // used only to offset the lo for CW,CWR
static int bridge_compensation = 100;
static double voice_clip_level = 0.04;
static int in_calibration = 1; // this turns off alc, clipping et al
static int in_calibration = 0; // cal off, turns on alc, clipping et al
static double ssb_val = 1.0; // W9JES
static double cw_bal = 1.0; // KD8CGH
static double ssb_bal = 1.0; // KD8CGH
int dsp_enabled = 0; // dsp W2JON
int anr_enabled = 0; // anr W2JON
int notch_enabled = 0; // notch filter W2JON
Expand Down Expand Up @@ -173,20 +185,22 @@ struct power_settings
{
int f_start;
int f_stop;
int max_watts;
float max_watts;
double scale;
};

struct power_settings band_power[] = {
{3500000, 4000000, 37, 0.002},
{3500000, 4000000, 40, 0.002},
{5251500, 5360000, 40, 0.0015},
{7000000, 7300009, 40, 0.0015},
{10000000, 10200000, 35, 0.0019},
{14000000, 14300000, 35, 0.0025},
{18000000, 18200000, 20, 0.0023},
{10000000, 10200000, 40, 0.0019},
{14000000, 14300000, 30, 0.0025},
{18000000, 18200000, 25, 0.0023},
{21000000, 21450000, 20, 0.003},
{24800000, 25000000, 20, 0.0034},
{28000000, 29700000, 20, 0.0037}};
{24800000, 25000000, 15, 0.0034},
{28000000, 29700000, 12, 0.0037}};

extern int mwatts_index; // assign for use in alc

#define CMD_TX (2)
#define CMD_RX (3)
Expand Down Expand Up @@ -1146,7 +1160,6 @@ void rx_linear(int32_t *input_rx, int32_t *input_mic,
{
int i = 0;
double i_sample;

// STEP 1: First add the previous M samples
// memcpy to replace for loop, ffts are 16 bytes
memcpy(fft_in, fft_m, MAX_BINS / 2 * 8 * 2);
Expand Down Expand Up @@ -1531,20 +1544,40 @@ void read_power()
uint8_t response[4];
int16_t vfwd, vref;
int fwdpw;

char buff[20];

float rfwatts;
char msg[50];
static int last_vfwd = 0; // check for change

/*
static uint64_t last_ns = 0; // timing
uint64_t delta_ns;
uint64_t t = now_ns();
static float read_dt;
float dt_ms=0.0;
if (last_ns != 0) {
delta_ns = t - last_ns;
// printf("Δt = %.3f ms\n", delta_ns / 1e6);
}
last_ns = t;
dt_ms = delta_ns / 1e6;
*/
if (!in_tx)
return;
if (i2cbb_read_i2c_block_data(0x8, 0, 4, response) == -1)
return;

vfwd = vref = 0;

memcpy(&vfwd, response, 2);
memcpy(&vfwd, response, 2); // raw reads
memcpy(&vref, response + 2, 2);
// printf("%d:%d\n", vfwd, vref);

// printf("%d %d %.1f\n", vfwd, last_vfwd, dt_ms);
// read_dt += dt_ms;
if ( vfwd == last_vfwd) return; // no change so do nothing

last_vfwd = vfwd;



// Very low power readings may spoil the swr calculation, especially in CW modes between symbols
// Better not to calculate the swr at all if the measured power is under a very minimal level
if (vfwd > 3) {
Expand All @@ -1556,35 +1589,42 @@ void read_power()

// here '400' is the scaling factor as our ref power output is 40 watts
// this calculates the power as 1/10th of a watt, 400 = 40 watts
int fwdvoltage = (vfwd * 40) / bridge_compensation;

// Implement a simple "hold" algorithm in order to show
// readable and meaningful power readings that should be the pep power
fwdpw = (fwdvoltage * fwdvoltage) / 400;
if (fwdpw > fwdpower_calc) {
fwdpower_calc = fwdpw;
}
if (!fwdpower_cnt) {
fwdpower = fwdpower_calc;
fwdpower_calc = fwdpw;
}
if (!fwdpower)
fwdpower = fwdpw;
fwdpower_cnt = ++fwdpower_cnt % 100;

int rf_v_p2p = (fwdvoltage * 126) / 400;
// printf("rf volts: %d, alc %g, %d watts ", rf_v_p2p, alc_level, fwdpower/10);
if (rf_v_p2p > 135 && !in_calibration)
{
alc_level *= 135.0 / (1.0 * rf_v_p2p);
printf("ALC tripped, to %d percent\n", (int)(100 * alc_level));
}
/* else if (alc_level < 0.95){
printf("alc releasing to ");
alc_level *= 1.02;

fwdvoltage = (vfwd * 40.0) / bridge_compensation;
fwdpw = (fwdvoltage * fwdvoltage) / 400; // watts*10
if ( fwdpw > 0 ) { // displayed power expoential smoothing a=.5
fwdpower = (2*fwdpw + 2*fwdpower)/4;
} else {
fwdpower = fwdpw; // start
}
// fwdpower = fwdpw;
if (vfwd > 1020) { // check global limit by raw voltage read, max 1023
alc_level = 0.5;
snprintf(msg, sizeof(msg), "\nglobal ALC tripped at 42 watts\n");
write_console(STYLE_LOG, msg);
return;
}
// printf("fwdvoltage %.1f vrms %.1f fwdpw %d fwdpower %d \n",fwdvoltage,vrms,fwdpw,fwdpower);

vrms = (vfwd * 40.0 * 0.1118) / bridge_compensation; // not smoothed
rfwatts = vrms * vrms/50; // now, not smoothed
// printf("rfwatts %.1f fwdpw %d vfwd %d alc %4f read_dt %.1f\n",rfwatts, fwdpw, vfwd, alc_level, read_dt);
if ( rfwatts > band_power[cur_band].max_watts && !in_calibration)
{
alc_level = alc_level-.06;
// printf("max_watts %f rfwatts %f ALC tripped %f vfwd %d\n",band_power[cur_band].max_watts,
// rfwatts, alc_level,vfwd);
snprintf(msg, sizeof(msg), "\nband ALC at %.1f watts limit\n", band_power[cur_band].max_watts);
write_console(STYLE_LOG, msg);

} else if (alc_level < 0.991){
alc_level += .01;
// snprintf(msg, sizeof(msg), "\n ALC releasing to %.2f\n", alc_level);
// write_console(STYLE_LOG, msg);
// printf("alc releasing to %f \n",alc_level);
}
*/
// printf("alc: %g\n", alc_level);
// read_dt=0.0; // reset timer
// printf("in_calibratn %d\n", in_calibration);
}

static int tx_process_restart = 0;
Expand Down Expand Up @@ -1690,7 +1730,7 @@ void tx_process(
int m = 0;
int j = 0;
double i_sample_max = 0.0;
double i_sample_old = 0.0;
double i_samples = 0.0;
// double max = -10.0, min = 10.0;
// gather the samples into a time domain array
for (i = MAX_BINS / 2; i < MAX_BINS; i++)
Expand All @@ -1700,8 +1740,10 @@ void tx_process(
i_sample = (1.0 * (vfo_read(&tone_a) + vfo_read(&tone_b))) / 50000000000.0;
else if (r->mode == MODE_CALIBRATE)
i_sample = (1.0 * (vfo_read(&tone_a))) / 30000000000.0;
else if (r->mode == MODE_CW || r->mode == MODE_CWR || r->mode == MODE_FT8 || r->mode == MODE_FT4)
else if (r->mode == MODE_CW || r->mode == MODE_FT8 || r->mode == MODE_FT4)
i_sample = modem_next_sample(r->mode) / 3;
else if (r->mode == MODE_CWR)
i_sample = (modem_next_sample(r->mode) / 3) * cw_bal; // reduce CWR to CW level KD8CGH
else if (r->mode == MODE_AM)
{
// double modulation = (1.0 * vfo_read(&tone_a)) / 1073741824.0;
Expand All @@ -1723,14 +1765,17 @@ void tx_process(
} else {
i_sample = (1.0 * input_mic[j]) / 2000000000.0;
}
if (r->mode == MODE_LSB)
i_sample = i_sample * ssb_bal; // reduce LSB to USB level KD8CGH

}

// clip the overdrive to prevent damage up the processing chain, PA
if (r->mode == MODE_USB || r->mode == MODE_LSB || r->mode == MODE_AM)
{
i_sample_max = fmax(i_sample, i_sample_max); // find peak value
i_sample_max = 0.5 * i_sample_max + 0.5 * i_sample_old;
i_sample_old = i_sample_max; // do exponential smoothing
// i_sample_max = 0.4 * i_sample_max + 0.6 * i_samples; // do exponential smoothing on max
// i_samples = i_sample_max;

if (i_sample < (-1.0 * voice_clip_level))
i_sample = -1.0 * voice_clip_level;
Expand Down Expand Up @@ -1768,10 +1813,10 @@ void tx_process(
__imag__ fft_in[i] = q_sample;
m++;

vmax = i_sample_max*1.0/voice_clip_level; // scale to 1.0

i_sample_max=0.0;

}
vmax = i_sample_max*1.0/voice_clip_level; // scale to 1.0


// push the samples to the remote audio queue, decimated to 16000 samples/sec
for (i = 0; i < MAX_BINS / 2; i += 6) {
Expand Down Expand Up @@ -1809,7 +1854,8 @@ void tx_process(
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
// adjust USB/CW modulation power factor W9JES

if (r->mode == MODE_LSB || r->mode ==MODE_USB) // adjust SSB modulation power factor KD8CGH
for (i = 0; i < MAX_BINS / 2; i++)
{
__real__ fft_out[i] = __real__ fft_out[i] * ssb_val;
Expand Down Expand Up @@ -1849,7 +1895,7 @@ void tx_process(
max = output_tx[i];
// output_tx[i] = 0;
}
// printf("min %d, max %d\n", min, max);
// printf("alc_level %f ", alc_level);

read_power();

Expand Down Expand Up @@ -2065,13 +2111,21 @@ static int hw_settings_handler(void *user, const char *section,
band_power[hw_init_index].f_start = atoi(value);
if (!strcmp(name, "f_stop"))
band_power[hw_init_index].f_stop = atoi(value);
if (!strcmp(name, "max_watts"))
band_power[hw_init_index].max_watts = atof(value);
if (!strcmp(name, "scale"))
band_power[hw_init_index++].scale = atof(value);
if (!strcmp(name, "bfo_freq"))
bfo_freq = atoi(value);
// Add variable for SSB/CW Power Factor Adjustment W9JES
if (!strcmp(name, "ssb_val"))
ssb_val = atof(value);
if (!strcmp(name, "ssb_bal"))
ssb_bal = atof(value);
if (!strcmp(name, "cw_bal")) {
cw_bal = atof(value);
printf("cw_bal %f\n", cw_bal);
}
// Add TCXO Calibration W9JES/KK4DAS
if (!strcmp(section, "tcxo"))
{
Expand Down Expand Up @@ -2153,16 +2207,16 @@ void calibrate_band_power(struct power_settings *b)
set_tx_power_levels();
delay(50); // let the new power levels take hold

int avg = 0;
float avg = 0;
// take many readings to get a peak
for (j = 0; j < 10; j++)
{
delay(20);
avg += fwdpower / 10; // fwdpower in 1/10th of a watt
// printf(" avg %d, fwd %d scale %g\n", avg, fwdpower, b->scale);
avg += fwdpower; // fwdpower in watts
// printf(" avg %d, fwd %d scale %g\n", avg, fwdpower, b->scale);
}
avg /= 10;
printf("*%d, f %d : avg %d, max = %d\n", i, b->f_start, avg, b->max_watts);
avg /= 10.0;
printf("*%d, f %d : avg %f, max = %f\n", i, b->f_start, avg, b->max_watts);
if (avg >= b->max_watts)
break;
}
Expand Down Expand Up @@ -2191,8 +2245,9 @@ void save_hw_settings()
// now save the band stack
for (int i = 0; i < sizeof(band_power) / sizeof(struct power_settings); i++)
{
fprintf(f, "[tx_band]\nf_start=%d\nf_stop=%d\nscale=%g\n\n",
band_power[i].f_start, band_power[i].f_stop, band_power[i].scale);
fprintf(f, "[tx_band]\nf_start=%d\nf_stop=%d\nmax_watts=%f\nscale=%g\n\n",
band_power[i].f_start, band_power[i].f_stop,
band_power[i].max_watts, band_power[i].scale);
}

fclose(f);
Expand Down Expand Up @@ -2263,10 +2318,7 @@ void tr_switch(int tx_on) {
spectrum_reset();

// Also reset the hold counter for showing the output power
fwdpower_cnt = 0;
fwdpower_calc = 0;
fwdpower = 0;

} else { // switch to receive
in_tx = 0; // lower the transmit flag
sound_mixer(audio_card, "Master", 0); // mute audio while switching to receive
Expand All @@ -2283,9 +2335,9 @@ void tr_switch(int tx_on) {
spectrum_reset();

// Also reset the hold counter for showing the output power
fwdpower_cnt = 0;
fwdpower_calc = 0;
fwdpower = 0;
alc_level = 1.0; // reset alc KD8CGH
// printf("\nalc level reset to %f\n",alc_level);
}
}

Expand Down
2 changes: 2 additions & 0 deletions src/sbitx_gtk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,7 @@ extern struct rx *rx_list;
extern char *cw_get_stats(char *buf, size_t len);
/* VSWR trip flag Clear on band change so previous trips don't persist. */
extern int vswr_tripped;
extern int cur_band;
extern float vmax; // vlevel meter, now with log voltage levels - not power
float vlevels[12]= {.1, .126, .158, .2, .25, .316, .398, .5, .631, .794, 1.0, 1.26};
void change_band(char *request);
Expand Down Expand Up @@ -5109,6 +5110,7 @@ struct band *get_band_by_frequency(int frequency)
// Use the start and stop fields to define the band edges
if (frequency >= band_stack[i].start && frequency <= band_stack[i].stop)
{
cur_band = i; // set current band for alc
return &band_stack[i]; // Return a pointer to the matching band
}
}
Expand Down