Started demodulator class based on rtl_fm.c

This commit is contained in:
Charles J. Cliffe 2014-11-04 21:55:20 -05:00
parent a1d76f1e11
commit f22a929828
5 changed files with 1056 additions and 2 deletions

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@ -80,6 +80,7 @@ SET (cubicsdr_sources
src/AppFrame.cpp
src/SDRThreadQueue.cpp
src/SDRThreadTask.cpp
src/Demodulate.cpp
)
SET (cubicsdr_headers
@ -91,6 +92,7 @@ SET (cubicsdr_headers
src/CubicSDRDefs.h
src/SDRThreadQueue.h
src/SDRThreadTask.h
src/Demodulate.h
)
#configure_files(${PROJECT_SOURCE_DIR}/shaders ${PROJECT_BINARY_DIR}/shaders COPYONLY)
#configure_files(${PROJECT_SOURCE_DIR}/png ${PROJECT_BINARY_DIR}/png COPYONLY)

966
src/Demodulate.cpp Normal file
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@ -0,0 +1,966 @@
#include "Demodulate.h"
#include "CubicSDRDefs.h"
#include <math.h>
#include <cstring>
#include <stdlib.h>
#include <iostream>
#define DEFAULT_SAMPLE_RATE 24000
#define DEFAULT_BUF_LENGTH (1 * 16384)
#define MAXIMUM_OVERSAMPLE 16
#define MAXIMUM_BUF_LENGTH (MAXIMUM_OVERSAMPLE * DEFAULT_BUF_LENGTH)
#define AUTO_GAIN -100
#define BUFFER_DUMP 4096
#define MAXIMUM_RATE 2400000
#define PI_INT (1<<14)
#define ONE_INT (1<<14)
static int *atan_lut = NULL;
static int atan_lut_size = 131072; /* 512 KB */
static int atan_lut_coef = 8;
// rewrite as dynamic and thread-safe for multi demod/dongle
#define SHARED_SIZE 6
int16_t shared_samples[SHARED_SIZE][MAXIMUM_BUF_LENGTH];
int ss_busy[SHARED_SIZE] = { 0 };
/* more cond dumbness */
#define safe_cond_signal(n, m) pthread_mutex_lock(m); pthread_cond_signal(n); pthread_mutex_unlock(m)
#define safe_cond_wait(n, m) pthread_mutex_lock(m); pthread_cond_wait(n, m); pthread_mutex_unlock(m)
/* {length, coef, coef, coef} and scaled by 2^15
for now, only length 9, optimal way to get +85% bandwidth */
#define CIC_TABLE_MAX 10
int cic_9_tables[][10] = { { 0, }, { 9, -156, -97, 2798, -15489, 61019, -15489, 2798, -97, -156 }, { 9, -128, -568, 5593, -24125, 74126, -24125, 5593,
-568, -128 }, { 9, -129, -639, 6187, -26281, 77511, -26281, 6187, -639, -129 },
{ 9, -122, -612, 6082, -26353, 77818, -26353, 6082, -612, -122 }, { 9, -120, -602, 6015, -26269, 77757, -26269, 6015, -602, -120 }, { 9, -120,
-582, 5951, -26128, 77542, -26128, 5951, -582, -120 }, { 9, -119, -580, 5931, -26094, 77505, -26094, 5931, -580, -119 }, { 9, -119,
-578, 5921, -26077, 77484, -26077, 5921, -578, -119 }, { 9, -119, -577, 5917, -26067, 77473, -26067, 5917, -577, -119 }, { 9, -199,
-362, 5303, -25505, 77489, -25505, 5303, -362, -199 }, };
#ifdef _MSC_VER
double log2(double n)
{
return log(n) / log(2.0);
}
#endif
void rotate_90(unsigned char *buf, uint32_t len)
/* 90 rotation is 1+0j, 0+1j, -1+0j, 0-1j
or [0, 1, -3, 2, -4, -5, 7, -6] */
{
uint32_t i;
unsigned char tmp;
for (i = 0; i < len; i += 8) {
/* uint8_t negation = 255 - x */
tmp = 255 - buf[i + 3];
buf[i + 3] = buf[i + 2];
buf[i + 2] = tmp;
buf[i + 4] = 255 - buf[i + 4];
buf[i + 5] = 255 - buf[i + 5];
tmp = 255 - buf[i + 6];
buf[i + 6] = buf[i + 7];
buf[i + 7] = tmp;
}
}
int translate_init(struct translate_state *ts)
/* two pass: first to find optimal length, second to alloc/fill */
{
int max_length = 100000;
int i, s, c, best_i;
double a, a2, err, best_360;
if (fabs(ts->angle) < 2 * M_PI / max_length) {
std::cout << "angle too small or array too short\n" << std::endl;
return 1;
}
ts->i = 0;
ts->sincos = NULL;
if (ts->len) {
max_length = ts->len;
ts->sincos = (int16_t *) malloc(max_length * sizeof(int16_t));
}
a = 0.0;
err = 0.0;
best_i = 0;
best_360 = 4.0;
for (i = 0; i < max_length; i += 2) {
s = (int) round(sin(a + err) * (1 << 14));
c = (int) round(cos(a + err) * (1 << 14));
a2 = atan2(s, c);
err = fmod(a, 2 * M_PI) - a2;
a += ts->angle;
while (a > M_PI) {
a -= 2 * M_PI;
}
while (a < -M_PI) {
a += 2 * M_PI;
}
if (i != 0 && fabs(a) < best_360) {
best_i = i;
best_360 = fabs(a);
}
if (i != 0 && fabs(a) < 0.0000001) {
break;
}
if (ts->sincos) {
ts->sincos[i] = s;
ts->sincos[i + 1] = c;
//fprintf(stderr, "%i %i %i\n", i, s, c);
}
}
if (ts->sincos) {
return 0;
}
ts->len = best_i + 2;
return translate_init(ts);
}
void translate(Demodulate *d) {
int i, len, sc_i, sc_len;
int32_t tmp, ar, aj, br, bj;
int16_t *buf = d->lowpassed;
int16_t *sincos = d->rotate.sincos;
len = d->lp_len;
sc_i = d->rotate.i;
sc_len = d->rotate.len;
for (i = 0; i < len; i += 2, sc_i += 2) {
sc_i = sc_i % sc_len;
ar = (int32_t) buf[i];
aj = (int32_t) buf[i + 1];
br = (int32_t) sincos[sc_i];
bj = (int32_t) sincos[sc_i + 1];
tmp = ar * br - aj * bj;
buf[i] = (int16_t) (tmp >> 14);
tmp = aj * br + ar * bj;
buf[i + 1] = (int16_t) (tmp >> 14);
}
d->rotate.i = sc_i;
}
void low_pass(Demodulate *d)
/* simple square window FIR */
{
int i = 0, i2 = 0;
while (i < d->lp_len) {
d->now_r += d->lowpassed[i];
d->now_j += d->lowpassed[i + 1];
i += 2;
d->prev_index++;
if (d->prev_index < d->downsample) {
continue;
}
d->lowpassed[i2] = d->now_r; // * d->output_scale;
d->lowpassed[i2 + 1] = d->now_j; // * d->output_scale;
d->prev_index = 0;
d->now_r = 0;
d->now_j = 0;
i2 += 2;
}
d->lp_len = i2;
}
int low_pass_simple(int16_t *signal2, int len, int step)
// no wrap around, length must be multiple of step
{
int i, i2, sum;
for (i = 0; i < len; i += step) {
sum = 0;
for (i2 = 0; i2 < step; i2++) {
sum += (int) signal2[i + i2];
}
//signal2[i/step] = (int16_t)(sum / step);
signal2[i / step] = (int16_t) (sum);
}
signal2[i / step + 1] = signal2[i / step];
return len / step;
}
void low_pass_real(Demodulate *s)
/* simple square window FIR */
// add support for upsampling?
{
int16_t *lp = s->lowpassed;
int i = 0, i2 = 0;
int fast = (int) s->rate_out;
int slow = s->rate_out2;
while (i < s->lp_len) {
s->now_lpr += lp[i];
i++;
s->prev_lpr_index += slow;
if (s->prev_lpr_index < fast) {
continue;
}
lp[i2] = (int16_t) (s->now_lpr / (fast / slow));
s->prev_lpr_index -= fast;
s->now_lpr = 0;
i2 += 1;
}
s->lp_len = i2;
}
void fifth_order(int16_t *data, int length, int16_t *hist)
/* for half of interleaved data */
{
int i;
int16_t a, b, c, d, e, f;
a = hist[1];
b = hist[2];
c = hist[3];
d = hist[4];
e = hist[5];
f = data[0];
/* a downsample should improve resolution, so don't fully shift */
data[0] = (a + (b + e) * 5 + (c + d) * 10 + f) >> 4;
for (i = 4; i < length; i += 4) {
a = c;
b = d;
c = e;
d = f;
e = data[i - 2];
f = data[i];
data[i / 2] = (a + (b + e) * 5 + (c + d) * 10 + f) >> 4;
}
/* archive */
hist[0] = a;
hist[1] = b;
hist[2] = c;
hist[3] = d;
hist[4] = e;
hist[5] = f;
}
void generic_fir(int16_t *data, int length, int *fir, int16_t *hist)
/* Okay, not at all generic. Assumes length 9, fix that eventually. */
{
int d, temp, sum;
for (d = 0; d < length; d += 2) {
temp = data[d];
sum = 0;
sum += (hist[0] + hist[8]) * fir[1];
sum += (hist[1] + hist[7]) * fir[2];
sum += (hist[2] + hist[6]) * fir[3];
sum += (hist[3] + hist[5]) * fir[4];
sum += hist[4] * fir[5];
data[d] = sum >> 15;
hist[0] = hist[1];
hist[1] = hist[2];
hist[2] = hist[3];
hist[3] = hist[4];
hist[4] = hist[5];
hist[5] = hist[6];
hist[6] = hist[7];
hist[7] = hist[8];
hist[8] = temp;
}
}
/* define our own complex math ops
because ARMv5 has no hardware float */
void multiply(int ar, int aj, int br, int bj, int *cr, int *cj) {
*cr = ar * br - aj * bj;
*cj = aj * br + ar * bj;
}
int polar_discriminant(int ar, int aj, int br, int bj) {
int cr, cj;
double angle;
multiply(ar, aj, br, -bj, &cr, &cj);
angle = atan2((double) cj, (double) cr);
return (int) (angle / M_PI * (1 << 14));
}
int fast_atan2(int y, int x)
/* pre scaled for int16 */
{
int yabs, angle;
int pi4 = (1 << 12), pi34 = 3 * (1 << 12); // note pi = 1<<14
if (x == 0 && y == 0) {
return 0;
}
yabs = y;
if (yabs < 0) {
yabs = -yabs;
}
if (x >= 0) {
angle = pi4 - pi4 * (x - yabs) / (x + yabs);
} else {
angle = pi34 - pi4 * (x + yabs) / (yabs - x);
}
if (y < 0) {
return -angle;
}
return angle;
}
int polar_disc_fast(int ar, int aj, int br, int bj) {
int cr, cj;
multiply(ar, aj, br, -bj, &cr, &cj);
return fast_atan2(cj, cr);
}
int atan_lut_init(void) {
int i = 0;
atan_lut = (int *) malloc(atan_lut_size * sizeof(int));
for (i = 0; i < atan_lut_size; i++) {
atan_lut[i] = (int) (atan((double) i / (1 << atan_lut_coef)) / M_PI * (1 << 14));
}
return 0;
}
int polar_disc_lut(int ar, int aj, int br, int bj) {
int cr, cj, x, x_abs;
multiply(ar, aj, br, -bj, &cr, &cj);
/* special cases */
if (cr == 0 || cj == 0) {
if (cr == 0 && cj == 0) {
return 0;
}
if (cr == 0 && cj > 0) {
return 1 << 13;
}
if (cr == 0 && cj < 0) {
return -(1 << 13);
}
if (cj == 0 && cr > 0) {
return 0;
}
if (cj == 0 && cr < 0) {
return 1 << 14;
}
}
/* real range -32768 - 32768 use 64x range -> absolute maximum: 2097152 */
x = (cj << atan_lut_coef) / cr;
x_abs = abs(x);
if (x_abs >= atan_lut_size) {
/* we can use linear range, but it is not necessary */
return (cj > 0) ? 1 << 13 : -1 << 13;
}
if (x > 0) {
return (cj > 0) ? atan_lut[x] : atan_lut[x] - (1 << 14);
} else {
return (cj > 0) ? (1 << 14) - atan_lut[-x] : -atan_lut[-x];
}
return 0;
}
int esbensen(int ar, int aj, int br, int bj)
/*
input signal: s(t) = a*exp(-i*w*t+p)
a = amplitude, w = angular freq, p = phase difference
solve w
s' = -i(w)*a*exp(-i*w*t+p)
s'*conj(s) = -i*w*a*a
s'*conj(s) / |s|^2 = -i*w
*/
{
int cj, dr, dj;
int scaled_pi = 2608; /* 1<<14 / (2*pi) */
dr = (br - ar) * 2;
dj = (bj - aj) * 2;
cj = bj * dr - br * dj; /* imag(ds*conj(s)) */
return (scaled_pi * cj / (ar * ar + aj * aj + 1));
}
void fm_demod(Demodulate *fm) {
int i, pcm = 0;
int16_t *lp = fm->lowpassed;
int16_t pr = fm->pre_r;
int16_t pj = fm->pre_j;
for (i = 0; i < (fm->lp_len - 1); i += 2) {
switch (fm->custom_atan) {
case 0:
pcm = polar_discriminant(lp[i], lp[i + 1], pr, pj);
break;
case 1:
pcm = polar_disc_fast(lp[i], lp[i + 1], pr, pj);
break;
case 2:
pcm = polar_disc_lut(lp[i], lp[i + 1], pr, pj);
break;
case 3:
pcm = esbensen(lp[i], lp[i + 1], pr, pj);
break;
}
pr = lp[i];
pj = lp[i + 1];
fm->lowpassed[i / 2] = (int16_t) pcm;
}
fm->pre_r = pr;
fm->pre_j = pj;
fm->lp_len = fm->lp_len / 2;
}
void am_demod(Demodulate *fm)
// todo, fix this extreme laziness
{
int32_t i, pcm;
int16_t *lp = fm->lowpassed;
for (i = 0; i < fm->lp_len; i += 2) {
// hypot uses floats but won't overflow
//r[i/2] = (int16_t)hypot(lp[i], lp[i+1]);
pcm = lp[i] * lp[i];
pcm += lp[i + 1] * lp[i + 1];
lp[i / 2] = (int16_t) sqrt(pcm) * fm->output_scale;
}
fm->lp_len = fm->lp_len / 2;
// lowpass? (3khz)
}
void usb_demod(Demodulate *fm) {
int i, pcm;
int16_t *lp = fm->lowpassed;
for (i = 0; i < fm->lp_len; i += 2) {
pcm = lp[i] + lp[i + 1];
lp[i / 2] = (int16_t) pcm * fm->output_scale;
}
fm->lp_len = fm->lp_len / 2;
}
void lsb_demod(Demodulate *fm) {
int i, pcm;
int16_t *lp = fm->lowpassed;
for (i = 0; i < fm->lp_len; i += 2) {
pcm = lp[i] - lp[i + 1];
lp[i / 2] = (int16_t) pcm * fm->output_scale;
}
fm->lp_len = fm->lp_len / 2;
}
void raw_demod(Demodulate *fm) {
return;
}
void deemph_filter(Demodulate *fm) {
static int avg; // cheating, not threadsafe
int i, d;
int16_t *lp = fm->lowpassed;
// de-emph IIR
// avg = avg * (1 - alpha) + sample * alpha;
for (i = 0; i < fm->lp_len; i++) {
d = lp[i] - avg;
if (d > 0) {
avg += (d + fm->deemph_a / 2) / fm->deemph_a;
} else {
avg += (d - fm->deemph_a / 2) / fm->deemph_a;
}
lp[i] = (int16_t) avg;
}
}
void dc_block_filter(Demodulate *fm) {
int i, avg;
int64_t sum = 0;
int16_t *lp = fm->lowpassed;
for (i = 0; i < fm->lp_len; i++) {
sum += lp[i];
}
avg = sum / fm->lp_len;
avg = (avg + fm->dc_avg * 9) / 10;
for (i = 0; i < fm->lp_len; i++) {
lp[i] -= avg;
}
fm->dc_avg = avg;
}
int mad(int16_t *samples, int len, int step)
/* mean average deviation */
{
int i = 0, sum = 0, ave = 0;
if (len == 0) {
return 0;
}
for (i = 0; i < len; i += step) {
sum += samples[i];
}
ave = sum / (len * step);
sum = 0;
for (i = 0; i < len; i += step) {
sum += abs(samples[i] - ave);
}
return sum / (len / step);
}
int rms(int16_t *samples, int len, int step)
/* largely lifted from rtl_power */
{
int i;
long p, t, s;
double dc, err;
p = t = 0L;
for (i = 0; i < len; i += step) {
s = (long) samples[i];
t += s;
p += s * s;
}
/* correct for dc offset in squares */
dc = (double) (t * step) / (double) len;
err = t * 2 * dc - dc * dc * len;
return (int) sqrt((p - err) / len);
}
int squelch_to_rms(int db, struct dongle_state *dongle, Demodulate *demod)
/* 0 dB = 1 rms at 50dB gain and 1024 downsample */
{
double linear, gain, downsample;
if (db == 0) {
return 0;
}
linear = pow(10.0, (double) db / 20.0);
gain = 50.0;
// if (dongle->gain != AUTO_GAIN) {
// gain = (double) (dongle->gain) / 10.0;
// }
gain = 50.0 - gain;
gain = pow(10.0, gain / 20.0);
downsample = 1024.0 / (double) demod->downsample;
linear = linear / gain;
linear = linear / downsample;
return (int) linear + 1;
}
Demodulate::Demodulate() {
rate_in = DEFAULT_SAMPLE_RATE;
rate_out = DEFAULT_SAMPLE_RATE;
squelch_level = 0;
conseq_squelch = 10;
terminate_on_squelch = 0;
squelch_hits = 11;
downsample_passes = 0;
comp_fir_size = 0;
prev_index = 0;
post_downsample = 1; // once this works, default = 4
custom_atan = 0;
deemph = 0;
rotate_enable = 0;
rotate.len = 0;
rotate.sincos = NULL;
rate_out2 = -1; // flag for disabled
mode_demod = &fm_demod;
// pre_j = s->pre_r = s->now_r = s->now_j = 0;
prev_lpr_index = 0;
deemph_a = 0;
now_lpr = 0;
dc_block = 1;
dc_avg = 0;
output_target = &output.results[0];
lowpassed = NULL;
/*
int capture_freq, capture_rate;
struct dongle_state *d = &dongle;
struct demod_state *dm = &demod;
struct controller_state *cs = &controller;
dm->downsample = (MINIMUM_RATE / dm->rate_in) + 1;
if (dm->downsample_passes) {
dm->downsample_passes = (int)log2(dm->downsample) + 1;
dm->downsample = 1 << dm->downsample_passes;
}
capture_freq = freq;
capture_rate = dm->downsample * dm->rate_in;
if (d->pre_rotate) {
capture_freq = freq + capture_rate/4;}
capture_freq += cs->edge * dm->rate_in / 2;
dm->output_scale = (1<<15) / (128 * dm->downsample);
if (dm->output_scale < 1) {
dm->output_scale = 1;}
if (dm->mode_demod == &fm_demod) {
dm->output_scale = 1;}
d->freq = (uint32_t)capture_freq;
d->rate = (uint32_t)capture_rate;
*/
int r, opt;
int dev_given = 0;
int custom_ppm = 0;
output.results[0].trycond = 1;
output.results[0].buf = NULL;
output.results[1].trycond = 1;
output.results[1].buf = NULL;
// controller.freqs[0] = 100000000;
// controller.freq_len = 0;
// controller.edge = 0;
// controller.wb_mode = 0;
// if (strcmp("fm", optarg) == 0) {
// demod.mode_demod = &fm_demod;
// }
// if (strcmp("raw", optarg) == 0) {
// demod.mode_demod = &raw_demod;
// }
// if (strcmp("am", optarg) == 0) {
// demod.mode_demod = &am_demod;
// }
// if (strcmp("usb", optarg) == 0) {
// demod.mode_demod = &usb_demod;
// }
// if (strcmp("lsb", optarg) == 0) {
// demod.mode_demod = &lsb_demod;
// }
// if (strcmp("wbfm", optarg) == 0) {
// controller.wb_mode = 1;
mode_demod = &fm_demod;
rate_in = SRATE; //170000
rate_out = SRATE; //170000
rate_out2 = 32000;
output.rate = 32000;
custom_atan = 1;
//demod.post_downsample = 4;
deemph = 1;
squelch_level = 0;
// }
// break;
rate_in *= post_downsample;
if (!output.rate) {
output.rate = rate_out;
}
// if (controller.freq_len > 1) {
// terminate_on_squelch = 0;
// }
output.padded = 0;
}
void Demodulate::demod(std::vector<int16_t> &buffer) {
int i, ds_p;
int do_squelch = 0;
int sr = 0;
if (rotate_enable) {
translate(this);
}
ds_p = downsample_passes;
lowpassed = &buffer[0];
lp_len = buffer.size();
if (ds_p) {
for (i = 0; i < ds_p; i++) {
fifth_order(lowpassed, (lp_len >> i), lp_i_hist[i]);
fifth_order(lowpassed + 1, (lp_len >> i) - 1, lp_q_hist[i]);
}
lp_len = lp_len >> ds_p;
/* droop compensation */
if (comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) {
generic_fir(lowpassed, lp_len, cic_9_tables[ds_p], droop_i_hist);
generic_fir(lowpassed + 1, lp_len - 1, cic_9_tables[ds_p], droop_q_hist);
}
} else {
low_pass(this);
}
/* power squelch */
if (squelch_level) {
sr = rms(lowpassed, lp_len, 1);
if (sr < squelch_level) {
do_squelch = 1;
}
}
if (do_squelch) {
squelch_hits++;
for (i = 0; i < lp_len; i++) {
lowpassed[i] = 0;
}
} else {
squelch_hits = 0;
}
mode_demod(this); /* lowpassed -> lowpassed */
if (mode_demod == &raw_demod) {
return;
}
if (dc_block) {
dc_block_filter(this);
}
/* todo, fm noise squelch */
// use nicer filter here too?
if (post_downsample > 1) {
lp_len = low_pass_simple(lowpassed, lp_len, post_downsample);
}
if (deemph) {
deemph_filter(this);
}
if (rate_out2 > 0) {
low_pass_real(this);
}
}
/*
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) {
int i;
struct dongle_state *s = ctx;
struct demod_state *d = s->targets[0];
struct demod_state *d2 = s->targets[1];
if (do_exit) {
return;
}
if (!ctx) {
return;
}
if (s->mute) {
for (i = 0; i < s->mute; i++) {
buf[i] = 127;
}
s->mute = 0;
}
if (s->pre_rotate) {
rotate_90(buf, len);
}
for (i = 0; i < (int) len; i++) {
s->buf16[i] = (int16_t) buf[i] - 127;
}
if (d2 != NULL) {
pthread_rwlock_wrlock(&d2->rw);
d2->lowpassed = mark_shared_buffer();
memcpy(d2->lowpassed, s->buf16, 2 * len);
d2->lp_len = len;
pthread_rwlock_unlock(&d2->rw);
safe_cond_signal(&d2->ready, &d2->ready_m);
}
pthread_rwlock_wrlock(&d->rw);
d->lowpassed = s->buf16;
d->lp_len = len;
pthread_rwlock_unlock(&d->rw);
safe_cond_signal(&d->ready, &d->ready_m);
s->buf16 = mark_shared_buffer();
}
static void *demod_thread_fn(void *arg) {
struct demod_state *d = arg;
struct buffer_bucket *o = d->output_target;
while (!do_exit) {
safe_cond_wait(&d->ready, &d->ready_m);
pthread_rwlock_wrlock(&d->rw);
full_demod(d);
pthread_rwlock_unlock(&d->rw);
if (d->exit_flag) {
do_exit = 1;
}
pthread_rwlock_wrlock(&o->rw);
o->buf = d->lowpassed;
o->len = d->lp_len;
pthread_rwlock_unlock(&o->rw);
if (controller.freq_len > 1 && d->squelch_level && d->squelch_hits > d->conseq_squelch) {
unmark_shared_buffer(d->lowpassed);
d->squelch_hits = d->conseq_squelch + 1;
safe_cond_signal(&controller.hop, &controller.hop_m);
continue;
}
safe_cond_signal(&o->ready, &o->ready_m);
pthread_mutex_lock(&o->trycond_m);
o->trycond = 0;
pthread_mutex_unlock(&o->trycond_m);
}
return 0;
}
#ifndef _WIN32
static int get_nanotime(struct timespec *ts)
{
int rv = ENOSYS;
#ifdef __unix__
rv = clock_gettime(CLOCK_MONOTONIC, ts);
#elif __APPLE__
struct timeval tv;
rv = gettimeofday(&tv, NULL);
ts->tv_sec = tv.tv_sec;
ts->tv_nsec = tv.tv_usec * 1000L;
#endif
return rv;
}
#endif
static void *output_thread_fn(void *arg) {
int j, r = 0;
struct output_state *s = arg;
struct buffer_bucket *b0 = &s->results[0];
struct buffer_bucket *b1 = &s->results[1];
struct timespec start_time;
struct timespec now_time;
int64_t i, duration, samples, samples_now;
samples = 0L;
#ifndef _WIN32
get_nanotime(&start_time);
#endif
while (!do_exit) {
if (s->lrmix) {
safe_cond_wait(&b0->ready, &b0->ready_m);
pthread_rwlock_rdlock(&b0->rw);
safe_cond_wait(&b1->ready, &b1->ready_m);
pthread_rwlock_rdlock(&b1->rw);
for (j = 0; j < b0->len; j++) {
fwrite(b0->buf + j, 2, 1, s->file);
fwrite(b1->buf + j, 2, 1, s->file);
}
unmark_shared_buffer(b1->buf);
pthread_rwlock_unlock(&b1->rw);
unmark_shared_buffer(b0->buf);
pthread_rwlock_unlock(&b0->rw);
continue;
}
if (!s->padded) {
safe_cond_wait(&b0->ready, &b0->ready_m);
pthread_rwlock_rdlock(&b0->rw);
fwrite(b0->buf, 2, b0->len, s->file);
unmark_shared_buffer(b0->buf);
pthread_rwlock_unlock(&b0->rw);
continue;
}
#ifndef _WIN32
// padding requires output at constant rate
// pthread_cond_timedwait is terrible, roll our own trycond
// figure out how to do this with windows HPET
usleep(2000);
pthread_mutex_lock(&b0->trycond_m);
r = b0->trycond;
b0->trycond = 1;
pthread_mutex_unlock(&b0->trycond_m);
if (r == 0) {
pthread_rwlock_rdlock(&b0->rw);
fwrite(b0->buf, 2, b0->len, s->file);
unmark_shared_buffer(b0->buf);
samples += (int64_t)b0->len;
pthread_rwlock_unlock(&b0->rw);
continue;
}
get_nanotime(&now_time);
duration = now_time.tv_sec - start_time.tv_sec;
duration *= 1000000000L;
duration += (now_time.tv_nsec - start_time.tv_nsec);
samples_now = (duration * (int64_t)s->rate) / 1000000000L;
if (samples_now < samples) {
continue;}
for (i=samples; i<samples_now; i++) {
fputc(0, s->file);
fputc(0, s->file);
}
samples = samples_now;
#endif
}
return 0;
}
static void optimal_settings(int freq, int rate) {
// giant ball of hacks
// seems unable to do a single pass, 2:1
int capture_freq, capture_rate;
struct dongle_state *d = &dongle;
struct demod_state *dm = &demod;
struct controller_state *cs = &controller;
dm->downsample = (MINIMUM_RATE / dm->rate_in) + 1;
if (dm->downsample_passes) {
dm->downsample_passes = (int) log2(dm->downsample) + 1;
dm->downsample = 1 << dm->downsample_passes;
}
capture_freq = freq;
capture_rate = dm->downsample * dm->rate_in;
if (d->pre_rotate) {
capture_freq = freq + capture_rate / 4;
}
capture_freq += cs->edge * dm->rate_in / 2;
dm->output_scale = (1 << 15) / (128 * dm->downsample);
if (dm->output_scale < 1) {
dm->output_scale = 1;
}
if (dm->mode_demod == &fm_demod) {
dm->output_scale = 1;
}
d->freq = (uint32_t) capture_freq;
d->rate = (uint32_t) capture_rate;
//d->pre_rotate = 0;
//demod.rotate_enable = 1;
//demod.rotate.angle = -0.25 * 2 * M_PI;
//translate_init(&demod.rotate);
}
void optimal_lrmix(void) {
double angle1, angle2;
uint32_t freq, freq1, freq2, bw, dongle_bw, mr;
if (controller.freq_len != 2) {
fprintf(stderr, "error: lrmix requires two frequencies\n");
do_exit = 1;
exit(1);
}
if (output.padded) {
fprintf(stderr, "warning: lrmix does not support padding\n");
}
freq1 = controller.freqs[0];
freq2 = controller.freqs[1];
bw = demod.rate_out;
freq = freq1 / 2 + freq2 / 2 + bw;
mr = (uint32_t) abs((int64_t) freq1 - (int64_t) freq2) + bw;
if (mr > MINIMUM_RATE) {
MINIMUM_RATE = mr;
}
dongle.pre_rotate = 0;
optimal_settings(freq, bw);
output.padded = 0;
clone_demod(&demod2, &demod);
//demod2 = demod;
demod2.output_target = &output.results[1];
dongle.targets[1] = &demod2;
dongle_bw = dongle.rate;
if (dongle_bw > MAXIMUM_RATE) {
fprintf(stderr, "error: unable to find optimal settings\n");
do_exit = 1;
exit(1);
}
angle1 = ((double) freq1 - (double) freq) / (double) dongle_bw;
demod.rotate.angle = angle1 * 2 * M_PI;
angle2 = ((double) freq2 - (double) freq) / (double) dongle_bw;
demod2.rotate.angle = angle2 * 2 * M_PI;
translate_init(&demod.rotate);
translate_init(&demod2.rotate);
//fprintf(stderr, "a1 %f, a2 %f\n", angle1, angle2);
}
static void *controller_thread_fn(void *arg) {
// thoughts for multiple dongles
// might be no good using a controller thread if retune/rate blocks
int i;
struct controller_state *s = arg;
if (s->wb_mode) {
for (i = 0; i < s->freq_len; i++) {
s->freqs[i] += 16000;
}
}
// set up primary channel
optimal_settings(s->freqs[0], demod.rate_in);
demod.squelch_level = squelch_to_rms(demod.squelch_level, &dongle, &demod);
if (dongle.direct_sampling) {
verbose_direct_sampling(dongle.dev, dongle.direct_sampling);
}
if (dongle.offset_tuning) {
verbose_offset_tuning(dongle.dev);
}
// set up lrmix
if (output.lrmix) {
optimal_lrmix();
}
// Set the frequency
verbose_set_frequency(dongle.dev, dongle.freq);
fprintf(stderr, "Oversampling input by: %ix.\n", demod.downsample);
fprintf(stderr, "Oversampling output by: %ix.\n", demod.post_downsample);
fprintf(stderr, "Buffer size: %0.2fms\n", 1000 * 0.5 * (float) ACTUAL_BUF_LENGTH / (float) dongle.rate);
// Set the sample rate
verbose_set_sample_rate(dongle.dev, dongle.rate);
fprintf(stderr, "Output at %u Hz.\n", demod.rate_in / demod.post_downsample);
while (!do_exit) {
safe_cond_wait(&s->hop, &s->hop_m);
if (s->freq_len <= 1) {
continue;
}
if (output.lrmix) {
continue;
}
// hacky hopping
s->freq_now = (s->freq_now + 1) % s->freq_len;
optimal_settings(s->freqs[s->freq_now], demod.rate_in);
rtlsdr_set_center_freq(dongle.dev, dongle.freq);
dongle.mute = BUFFER_DUMP;
}
return 0;
}
int main(int argc, char **argv) {
}*/

85
src/Demodulate.h Normal file
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@ -0,0 +1,85 @@
#pragma once
/*
* based on rtl_fm.c
* https://github.com/keenerd/rtl-sdr/blob/master/src/rtl_fm.c
*/
#include <vector>
#include <stdint.h>
#include <stddef.h>
#define FREQUENCIES_LIMIT 1000
struct translate_state {
double angle; /* radians */
int16_t *sincos; /* pairs */
int len;
int i;
};
struct buffer_bucket {
int16_t *buf;
int len;
int trycond;
};
struct output_state {
int exit_flag;
struct buffer_bucket results[2];
int rate;
int wav_format;
int padded;
int lrmix;
};
struct controller_state {
int exit_flag;
uint32_t freqs[FREQUENCIES_LIMIT];
int freq_len;
int freq_now;
int edge;
int wb_mode;
};
class Demodulate {
public:
Demodulate();
~Demodulate() {
}
void demod(std::vector<int16_t> &buffer);
public:
int16_t *lowpassed;
int lp_len;
int16_t lp_i_hist[10][6];
int16_t lp_q_hist[10][6];
int16_t droop_i_hist[9];
int16_t droop_q_hist[9];
int rate_in;
int rate_out;
int rate_out2;
int now_r, now_j;
int pre_r, pre_j;
int prev_index;
int downsample; /* min 1, max 256 */
int post_downsample;
int output_scale;
int squelch_level, conseq_squelch, squelch_hits, terminate_on_squelch;
int downsample_passes;
int comp_fir_size;
int custom_atan;
int deemph, deemph_a;
int now_lpr;
int prev_lpr_index;
int dc_block, dc_avg;
int rotate_enable;
struct translate_state rotate;
void (*mode_demod)(Demodulate *);
struct buffer_bucket *output_target;
struct output_state output;
};

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@ -14,6 +14,7 @@
#include "CubicSDRDefs.h"
#include "AppFrame.h"
#include <algorithm>
#include "Demodulate.h"
wxString glGetwxString(GLenum name) {
const GLubyte *v = glGetString(name);

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@ -10,10 +10,10 @@ public:
};
SDRThreadTask() :
m_cmd(SDR_THREAD_NULL) {
m_cmd(SDR_THREAD_NULL), arg_int(0) {
}
SDRThreadTask(SDR_COMMAND cmd) :
m_cmd(cmd) {
arg_int(0), m_cmd(cmd) {
}
void setUInt(unsigned int i);