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Diffstat (limited to 'rtl_fm.c')
| -rw-r--r-- | rtl_fm.c | 1117 |
1 files changed, 1117 insertions, 0 deletions
diff --git a/rtl_fm.c b/rtl_fm.c new file mode 100644 index 0000000..dcf28ce --- /dev/null +++ b/rtl_fm.c @@ -0,0 +1,1117 @@ +/* + * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver + * Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de> + * Copyright (C) 2012 by Hoernchen <la@tfc-server.de> + * Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com> + * Copyright (C) 2013 by Elias Oenal <EliasOenal@gmail.com> + * Copyright (C) 2016 by Scott Murray <scott.murray@konsulko.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * Note that this version replaces the standalone main() with separate + * init/start/stop API calls to allow building into another application. + * Other than removing the separate controller thread and adding an output + * function callback, other changes have been kept to a minimum to + * potentially allow using other rtl_fm features by modifying rtl_fm_init. + * + * December 2016, Scott Murray <scott.murray@konsulko.com> + */ + +/* + * written because people could not do real time + * FM demod on Atom hardware with GNU radio + * based on rtl_sdr.c and rtl_tcp.c + * + * lots of locks, but that is okay + * (no many-to-many locks) + * + * todo: + * sanity checks + * scale squelch to other input parameters + * test all the demodulations + * pad output on hop + * frequency ranges could be stored better + * scaled AM demod amplification + * auto-hop after time limit + * peak detector to tune onto stronger signals + * fifo for active hop frequency + * clips + * noise squelch + * merge stereo patch + * merge soft agc patch + * merge udp patch + * testmode to detect overruns + * watchdog to reset bad dongle + * fix oversampling + */ + +#include <errno.h> +#include <signal.h> +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <math.h> +#include <pthread.h> + +#include "rtl-sdr.h" +#include "rtl_fm.h" +#include "convenience/convenience.h" + +#define DEFAULT_SAMPLE_RATE 24000 +#define DEFAULT_BUF_LENGTH RTL_FM_DEFAULT_BUF_LENGTH +#define MAXIMUM_OVERSAMPLE RTL_FM_MAXIMUM_OVERSAMPLE +#define MAXIMUM_BUF_LENGTH RTL_FM_MAXIMUM_BUF_LENGTH +#define AUTO_GAIN -100 +#define BUFFER_DUMP 4096 + +#define FREQUENCIES_LIMIT 1000 + +static volatile int do_exit = 0; +static int lcm_post[17] = {1,1,1,3,1,5,3,7,1,9,5,11,3,13,7,15,1}; +static int ACTUAL_BUF_LENGTH; + +static int *atan_lut = NULL; +static int atan_lut_size = 131072; /* 512 KB */ +static int atan_lut_coef = 8; + +struct dongle_state +{ + int exit_flag; + pthread_t thread; + rtlsdr_dev_t *dev; + int dev_index; + uint32_t freq; + uint32_t rate; + int gain; + uint16_t buf16[MAXIMUM_BUF_LENGTH]; + uint32_t buf_len; + int ppm_error; + int offset_tuning; + int direct_sampling; + int mute; + struct demod_state *demod_target; +}; + +struct demod_state +{ + int exit_flag; + pthread_t thread; + int16_t lowpassed[MAXIMUM_BUF_LENGTH]; + int lp_len; + int16_t lp_i_hist[10][6]; + int16_t lp_q_hist[10][6]; + int16_t result[MAXIMUM_BUF_LENGTH]; + int16_t droop_i_hist[9]; + int16_t droop_q_hist[9]; + int result_len; + 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; + void (*mode_demod)(struct demod_state*); + pthread_rwlock_t rw; + pthread_cond_t ready; + pthread_mutex_t ready_m; + struct output_state *output_target; +}; + +struct output_state +{ + int exit_flag; + pthread_t thread; + rtl_fm_output_fn_t output_fn; + void *output_fn_data; + int16_t result[MAXIMUM_BUF_LENGTH]; + int result_len; + int rate; + pthread_rwlock_t rw; + pthread_cond_t ready; + pthread_mutex_t ready_m; +}; + +struct controller_state +{ + int exit_flag; + pthread_t thread; + uint32_t freqs[FREQUENCIES_LIMIT]; + int freq_len; + int freq_now; + int edge; + int wb_mode; + pthread_cond_t hop; + pthread_mutex_t hop_m; +}; + +// multiple of these, eventually +struct dongle_state dongle; +struct demod_state demod; +struct output_state output; +struct controller_state controller; + +#if 0 +static void sighandler(int signum) +{ + fprintf(stderr, "Signal caught, exiting!\n"); + do_exit = 1; + rtlsdr_cancel_async(dongle.dev); +} +#endif + +/* 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}, +}; + +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; + } +} + +void low_pass(struct demod_state *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(struct demod_state *s) +/* simple square window FIR */ +// add support for upsampling? +{ + int i=0, i2=0; + int fast = (int)s->rate_out; + int slow = s->rate_out2; + while (i < s->result_len) { + s->now_lpr += s->result[i]; + i++; + s->prev_lpr_index += slow; + if (s->prev_lpr_index < fast) { + continue; + } + s->result[i2] = (int16_t)(s->now_lpr / (fast/slow)); + s->prev_lpr_index -= fast; + s->now_lpr = 0; + i2 += 1; + } + s->result_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 / 3.14159 * (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 = 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)) / 3.14159 * (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; +} + +void fm_demod(struct demod_state *fm) +{ + int i, pcm; + int16_t *lp = fm->lowpassed; + pcm = polar_discriminant(lp[0], lp[1], + fm->pre_r, fm->pre_j); + fm->result[0] = (int16_t)pcm; + for (i = 2; i < (fm->lp_len-1); i += 2) { + switch (fm->custom_atan) { + case 0: + pcm = polar_discriminant(lp[i], lp[i+1], + lp[i-2], lp[i-1]); + break; + case 1: + pcm = polar_disc_fast(lp[i], lp[i+1], + lp[i-2], lp[i-1]); + break; + case 2: + pcm = polar_disc_lut(lp[i], lp[i+1], + lp[i-2], lp[i-1]); + break; + } + fm->result[i/2] = (int16_t)pcm; + } + fm->pre_r = lp[fm->lp_len - 2]; + fm->pre_j = lp[fm->lp_len - 1]; + fm->result_len = fm->lp_len/2; +} + +void am_demod(struct demod_state *fm) +// todo, fix this extreme laziness +{ + int i, pcm; + int16_t *lp = fm->lowpassed; + int16_t *r = fm->result; + 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]; + r[i/2] = (int16_t)sqrt(pcm) * fm->output_scale; + } + fm->result_len = fm->lp_len/2; + // lowpass? (3khz) highpass? (dc) +} + +void usb_demod(struct demod_state *fm) +{ + int i, pcm; + int16_t *lp = fm->lowpassed; + int16_t *r = fm->result; + for (i = 0; i < fm->lp_len; i += 2) { + pcm = lp[i] + lp[i+1]; + r[i/2] = (int16_t)pcm * fm->output_scale; + } + fm->result_len = fm->lp_len/2; +} + +void lsb_demod(struct demod_state *fm) +{ + int i, pcm; + int16_t *lp = fm->lowpassed; + int16_t *r = fm->result; + for (i = 0; i < fm->lp_len; i += 2) { + pcm = lp[i] - lp[i+1]; + r[i/2] = (int16_t)pcm * fm->output_scale; + } + fm->result_len = fm->lp_len/2; +} + +void raw_demod(struct demod_state *fm) +{ + int i; + for (i = 0; i < fm->lp_len; i++) { + fm->result[i] = (int16_t)fm->lowpassed[i]; + } + fm->result_len = fm->lp_len; +} + +void deemph_filter(struct demod_state *fm) +{ + static int avg; // cheating... + int i, d; + // de-emph IIR + // avg = avg * (1 - alpha) + sample * alpha; + for (i = 0; i < fm->result_len; i++) { + d = fm->result[i] - avg; + if (d > 0) { + avg += (d + fm->deemph_a/2) / fm->deemph_a; + } else { + avg += (d - fm->deemph_a/2) / fm->deemph_a; + } + fm->result[i] = (int16_t)avg; + } +} + +void dc_block_filter(struct demod_state *fm) +{ + int i, avg; + int64_t sum = 0; + for (i=0; i < fm->result_len; i++) { + sum += fm->result[i]; + } + avg = sum / fm->result_len; + avg = (avg + fm->dc_avg * 9) / 10; + for (i=0; i < fm->result_len; i++) { + fm->result[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); +} + +void arbitrary_upsample(int16_t *buf1, int16_t *buf2, int len1, int len2) +/* linear interpolation, len1 < len2 */ +{ + int i = 1; + int j = 0; + int tick = 0; + double frac; // use integers... + while (j < len2) { + frac = (double)tick / (double)len2; + buf2[j] = (int16_t)(buf1[i-1]*(1-frac) + buf1[i]*frac); + j++; + tick += len1; + if (tick > len2) { + tick -= len2; + i++; + } + if (i >= len1) { + i = len1 - 1; + tick = len2; + } + } +} + +void arbitrary_downsample(int16_t *buf1, int16_t *buf2, int len1, int len2) +/* fractional boxcar lowpass, len1 > len2 */ +{ + int i = 1; + int j = 0; + int tick = 0; + double remainder = 0; + double frac; // use integers... + buf2[0] = 0; + while (j < len2) { + frac = 1.0; + if ((tick + len2) > len1) { + frac = (double)(len1 - tick) / (double)len2;} + buf2[j] += (int16_t)((double)buf1[i] * frac + remainder); + remainder = (double)buf1[i] * (1.0-frac); + tick += len2; + i++; + if (tick > len1) { + j++; + buf2[j] = 0; + tick -= len1; + } + if (i >= len1) { + i = len1 - 1; + tick = len1; + } + } + for (j=0; j<len2; j++) { + buf2[j] = buf2[j] * len2 / len1;} +} + +void arbitrary_resample(int16_t *buf1, int16_t *buf2, int len1, int len2) +/* up to you to calculate lengths and make sure it does not go OOB + * okay for buffers to overlap, if you are downsampling */ +{ + if (len1 < len2) { + arbitrary_upsample(buf1, buf2, len1, len2); + } else { + arbitrary_downsample(buf1, buf2, len1, len2); + } +} + +void full_demod(struct demod_state *d) +{ + int i, ds_p; + int sr = 0; + ds_p = d->downsample_passes; + if (ds_p) { + for (i=0; i < ds_p; i++) { + fifth_order(d->lowpassed, (d->lp_len >> i), d->lp_i_hist[i]); + fifth_order(d->lowpassed+1, (d->lp_len >> i) - 1, d->lp_q_hist[i]); + } + d->lp_len = d->lp_len >> ds_p; + /* droop compensation */ + if (d->comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) { + generic_fir(d->lowpassed, d->lp_len, + cic_9_tables[ds_p], d->droop_i_hist); + generic_fir(d->lowpassed+1, d->lp_len-1, + cic_9_tables[ds_p], d->droop_q_hist); + } + } else { + low_pass(d); + } + /* power squelch */ + if (d->squelch_level) { + sr = rms(d->lowpassed, d->lp_len, 1); + if (sr < d->squelch_level) { + d->squelch_hits++; + for (i=0; i<d->lp_len; i++) { + d->lowpassed[i] = 0; + } + } else { + d->squelch_hits = 0;} + } + d->mode_demod(d); /* lowpassed -> result */ + if (d->mode_demod == &raw_demod) { + return; + } + /* todo, fm noise squelch */ + // use nicer filter here too? + if (d->post_downsample > 1) { + d->result_len = low_pass_simple(d->result, d->result_len, d->post_downsample);} + if (d->deemph) { + deemph_filter(d);} + if (d->dc_block) { + dc_block_filter(d);} + if (d->rate_out2 > 0) { + low_pass_real(d); + //arbitrary_resample(d->result, d->result, d->result_len, d->result_len * d->rate_out2 / d->rate_out); + } +} + +static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) +{ + int i; + struct dongle_state *s = ctx; + struct demod_state *d = s->demod_target; + + 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->offset_tuning) { + rotate_90(buf, len);} + for (i=0; i<(int)len; i++) { + s->buf16[i] = (int16_t)buf[i] - 127;} + pthread_rwlock_wrlock(&d->rw); + memcpy(d->lowpassed, s->buf16, 2*len); + d->lp_len = len; + pthread_rwlock_unlock(&d->rw); + safe_cond_signal(&d->ready, &d->ready_m); +} + +static void *dongle_thread_fn(void *arg) +{ + struct dongle_state *s = arg; + fprintf(stderr, "dongle_thread_fn running\n"); + rtlsdr_read_async(s->dev, rtlsdr_callback, s, 0, s->buf_len); + fprintf(stderr, "dongle_thread_fn exited!\n"); + return 0; +} + +static void *demod_thread_fn(void *arg) +{ + struct demod_state *d = arg; + struct output_state *o = d->output_target; + fprintf(stderr, "demod_thread_fn running\n"); + 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; + } + if (d->squelch_level && d->squelch_hits > d->conseq_squelch) { + d->squelch_hits = d->conseq_squelch + 1; /* hair trigger */ + safe_cond_signal(&controller.hop, &controller.hop_m); + continue; + } + pthread_rwlock_wrlock(&o->rw); + memcpy(o->result, d->result, 2*d->result_len); + o->result_len = d->result_len; + pthread_rwlock_unlock(&o->rw); + safe_cond_signal(&o->ready, &o->ready_m); + } + fprintf(stderr, "demod_thread_fn exited!\n"); + return 0; +} + +static void *output_thread_fn(void *arg) +{ + struct output_state *s = arg; + fprintf(stderr, "output_thread_fn running\n"); + while (!do_exit) { + // use timedwait and pad out under runs + safe_cond_wait(&s->ready, &s->ready_m); + pthread_rwlock_rdlock(&s->rw); + if(s->output_fn) { + s->output_fn(s->result, s->result_len, s->output_fn_data); + } + pthread_rwlock_unlock(&s->rw); + } + fprintf(stderr, "output_thread_fn exited!\n"); + 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 = (1000000 / 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->offset_tuning) { + 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; +} + + +void frequency_range(struct controller_state *s, char *arg) +{ + char *start, *stop, *step; + int i; + start = arg; + stop = strchr(start, ':') + 1; + stop[-1] = '\0'; + step = strchr(stop, ':') + 1; + step[-1] = '\0'; + for(i=(int)atofs(start); i<=(int)atofs(stop); i+=(int)atofs(step)) + { + s->freqs[s->freq_len] = (uint32_t)i; + s->freq_len++; + if (s->freq_len >= FREQUENCIES_LIMIT) { + break;} + } + stop[-1] = ':'; + step[-1] = ':'; +} + +void dongle_init(struct dongle_state *s) +{ + s->rate = DEFAULT_SAMPLE_RATE; + s->gain = AUTO_GAIN; // tenths of a dB + s->mute = 0; + s->direct_sampling = 0; + s->offset_tuning = 0; + s->demod_target = &demod; +} + +void demod_init(struct demod_state *s) +{ + s->rate_in = DEFAULT_SAMPLE_RATE; + s->rate_out = DEFAULT_SAMPLE_RATE; + s->squelch_level = 0; + s->conseq_squelch = 10; + s->terminate_on_squelch = 0; + s->squelch_hits = 11; + s->downsample_passes = 0; + s->comp_fir_size = 0; + s->prev_index = 0; + s->post_downsample = 1; // once this works, default = 4 + s->custom_atan = 0; + s->deemph = 0; + s->rate_out2 = -1; // flag for disabled + s->mode_demod = &fm_demod; + s->pre_j = s->pre_r = s->now_r = s->now_j = 0; + s->prev_lpr_index = 0; + s->deemph_a = 0; + s->now_lpr = 0; + s->dc_block = 0; + s->dc_avg = 0; + pthread_rwlock_init(&s->rw, NULL); + pthread_cond_init(&s->ready, NULL); + pthread_mutex_init(&s->ready_m, NULL); + s->output_target = &output; +} + +void demod_cleanup(struct demod_state *s) +{ + pthread_rwlock_destroy(&s->rw); + pthread_cond_destroy(&s->ready); + pthread_mutex_destroy(&s->ready_m); +} + +void output_init(struct output_state *s) +{ + s->rate = DEFAULT_SAMPLE_RATE; + s->output_fn = NULL; + s->output_fn_data = NULL; + pthread_rwlock_init(&s->rw, NULL); + pthread_cond_init(&s->ready, NULL); + pthread_mutex_init(&s->ready_m, NULL); +} + +void output_cleanup(struct output_state *s) +{ + pthread_rwlock_destroy(&s->rw); + pthread_cond_destroy(&s->ready); + pthread_mutex_destroy(&s->ready_m); +} + +void controller_init(struct controller_state *s) +{ + s->freqs[0] = 100000000; + s->freq_len = 0; + s->edge = 0; + s->wb_mode = 0; + pthread_cond_init(&s->hop, NULL); + pthread_mutex_init(&s->hop_m, NULL); +} + +void controller_cleanup(struct controller_state *s) +{ + pthread_cond_destroy(&s->hop); + pthread_mutex_destroy(&s->hop_m); +} + +void sanity_checks(void) +{ + if (controller.freq_len == 0) { + fprintf(stderr, "Please specify a frequency.\n"); + exit(1); + } + + if (controller.freq_len >= FREQUENCIES_LIMIT) { + fprintf(stderr, "Too many channels, maximum %i.\n", FREQUENCIES_LIMIT); + exit(1); + } + + if (controller.freq_len > 1 && demod.squelch_level == 0) { + fprintf(stderr, "Please specify a squelch level. Required for scanning multiple frequencies.\n"); + exit(1); + } + +} + +int rtl_fm_init(uint32_t freq, + uint32_t sample_rate, + uint32_t resample_rate, + rtl_fm_output_fn_t output_fn, + void *output_fn_data) +{ + int r = 0; + + dongle_init(&dongle); + demod_init(&demod); + output_init(&output); + controller_init(&controller); + + /* + * Simulate the effects of command line arguments: + * + * -W wbfm -s <sample rate> -r <resample rate> + */ + + /* Set initial frequency */ + controller.freqs[0] = freq; + controller.freq_len++; + + /* Set mode to wbfm */ + controller.wb_mode = 1; + demod.mode_demod = &fm_demod; + demod.rate_in = 170000; + demod.rate_out = 170000; + demod.rate_out2 = 32000; + demod.custom_atan = 1; + //demod.post_downsample = 4; + demod.deemph = 1; + demod.squelch_level = 0; + + /* Set sample rate */ + demod.rate_in = sample_rate; + demod.rate_out = sample_rate; + + /* Set resample rate */ + output.rate = (int) resample_rate; + demod.rate_out2 = (int) resample_rate; + + /* Set output function pointer */ + if(output_fn) { + output.output_fn = output_fn; + output.output_fn_data = output_fn_data; + } + + /* quadruple sample_rate to limit to Δθ to ±π/2 */ + demod.rate_in *= demod.post_downsample; + + if (!output.rate) { + output.rate = demod.rate_out; + } + + sanity_checks(); + + if (controller.freq_len > 1) { + demod.terminate_on_squelch = 0; + } + + ACTUAL_BUF_LENGTH = lcm_post[demod.post_downsample] * DEFAULT_BUF_LENGTH; + + dongle.dev_index = verbose_device_search("0"); + if (dongle.dev_index < 0) { + return -1; + } + + r = rtlsdr_open(&dongle.dev, (uint32_t)dongle.dev_index); + if (r < 0) { + fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dongle.dev_index); + return r; + } + + if (demod.deemph) { + demod.deemph_a = (int)round(1.0/((1.0-exp(-1.0/(demod.rate_out * 75e-6))))); + } + + /* Set the tuner gain */ + if (dongle.gain == AUTO_GAIN) { + verbose_auto_gain(dongle.dev); + } else { + dongle.gain = nearest_gain(dongle.dev, dongle.gain); + verbose_gain_set(dongle.dev, dongle.gain); + } + + verbose_ppm_set(dongle.dev, dongle.ppm_error); + + //r = rtlsdr_set_testmode(dongle.dev, 1); + + return r; +} + +void rtl_fm_start(void) +{ + int i; + struct controller_state *s = &controller; + + /* + * A bunch of the following is pulled from the controller_thread_fn, + * which has been removed. + */ + + /* Reset endpoint before we start reading from it (mandatory) */ + verbose_reset_buffer(dongle.dev); + + 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); + if (dongle.direct_sampling) { + verbose_direct_sampling(dongle.dev, 1);} + if (dongle.offset_tuning) { + verbose_offset_tuning(dongle.dev);} + + /* 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); + usleep(100000); + + pthread_create(&output.thread, NULL, output_thread_fn, (void *)(&output)); + pthread_create(&demod.thread, NULL, demod_thread_fn, (void *)(&demod)); + pthread_create(&dongle.thread, NULL, dongle_thread_fn, (void *)(&dongle)); +} + +void rtl_fm_set_freq(uint32_t freq) +{ + int i; + struct controller_state *s = &controller; + struct demod_state *dm = &demod; + + s->freqs[0] = freq; + s->freq_len = 1; + + if (s->wb_mode) { + for (i=0; i < s->freq_len; i++) { + s->freqs[i] += 16000;} + } + + optimal_settings(s->freqs[0], demod.rate_in); + if (dongle.offset_tuning) { + verbose_offset_tuning(dongle.dev);} + rtlsdr_set_center_freq(dongle.dev, dongle.freq); + + // It does not look like refreshing the sample rate is desirable + // (e.g. the scanning code in the removed controller thread function + // did not do it), and behavior seemed a bit less robust with it + // present. However, I am leaving this here as a reminder to revisit + // via some more testing. + //rtlsdr_set_sample_rate(dongle.dev, dongle.rate); + + // This triggers a mute during the frequency change + dongle.mute = BUFFER_DUMP; +} + +void rtl_fm_stop(void) +{ + rtlsdr_cancel_async(dongle.dev); + pthread_join(dongle.thread, NULL); + safe_cond_signal(&demod.ready, &demod.ready_m); + pthread_join(demod.thread, NULL); + safe_cond_signal(&output.ready, &output.ready_m); + pthread_join(output.thread, NULL); +} + +void rtl_fm_cleanup(void) +{ + //dongle_cleanup(&dongle); + demod_cleanup(&demod); + output_cleanup(&output); + controller_cleanup(&controller); + + rtlsdr_close(dongle.dev); +} + +// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab |