mirror/rtl-sdr-blog
1
0
Fork 0
mirror of https://github.com/rtlsdrblog/rtl-sdr-blog.git synced 2024-12-25 10:28:28 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

rtl_fm: multithreaded and frequency scanning

Browse Source 
Signed-off-by: Steve Markgraf <steve@steve-m.de>
This commit is contained in:
Kyle Keen 2012-05-30 10:54:18 -04:00 committed by Steve Markgraf
parent defa7af74b
commit c3dde1db91
1 changed files with 51 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
src/rtl_fm.c
View File

@ -1,6 +1,8 @@
/*
* 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>
*
* 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
@ -20,14 +22,12 @@
/*
* written because people could not do real time
* FM demod on Atom hardware with GNU radio
* based on rtl_sdr.c
* based on rtl_sdr.c and rtl_tcp.c
* todo: realtime ARMv5
* remove float math (disqualifies complex.h)
* replace atan2 with a fast approximation
* in-place array operations
* wide band support
* refactor to look like rtl_tcp
* multiple frequency scanning
*/
#include <errno.h>
@ -43,6 +43,10 @@
#include <Windows.h>
#endif
#include <semaphore.h>
#include <pthread.h>
#include <libusb.h>
#include "rtl-sdr.h"
#define DEFAULT_SAMPLE_RATE 24000
@ -51,6 +55,8 @@
#define MINIMAL_BUF_LENGTH 512
#define MAXIMAL_BUF_LENGTH (256 * 16384)
static pthread_t demod_thread;
static sem_t data_ready;
static int do_exit = 0;
static rtlsdr_dev_t *dev = NULL;
@ -64,6 +70,8 @@ struct fm_state
int downsample; /* min 4, max 256 */
int output_scale;
int squelch_level;
uint8_t buf[DEFAULT_BUF_LENGTH];
uint32_t buf_len;
int signal[2048]; /* 16 bit signed i/q pairs */
int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
int signal_len;
@ -92,7 +100,7 @@ void usage(void)
"\t[-l squelch_level (default: 150)]\n"
"\t[-E freq sets lower edge (default: center)]\n"
"\tfilename (a '-' dumps samples to stdout)\n\n"
"Produces signed 16 bit ints, use sox to hear them.\n"
"Produces signed 16 bit ints, use Sox to hear them.\n"
"\trtl_fm ... | play -t raw -r 24k -e signed-integer -b 16 -c 1 -\n\n");
#endif
exit(1);
@ -258,14 +266,9 @@ static void optimal_settings(struct fm_state *fm, int freq, int hopping)
}
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
void full_demod(unsigned char *buf, uint32_t len, struct fm_state *fm2)
{
struct fm_state *fm2;
int sr, freq_next;
if (!ctx) {
return;
}
fm2 = (struct fm_struct*)(ctx); // warning?
rotate_90(buf, len);
low_pass(fm2, buf, len);
fm_demod(fm2);
@ -275,14 +278,41 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
if (fm2->freq_len > 1 && !sr) {
freq_next = (fm2->freq_now + 1) % fm2->freq_len;
optimal_settings(fm2, freq_next, 1);
rtlsdr_reset_buffer(dev);
//rtlsdr_read_async(dev, rtlsdr_callback, ctx,
// DEFAULT_ASYNC_BUF_NUMBER, DEFAULT_BUF_LENGTH);
//rtlsdr_wait_async(dev, rtlsdr_callback, (void *)0);
//rtlsdr_wait_async(dev, rtlsdr_callback, ctx);
// wait for settling and dump buffer
usleep(5000);
rtlsdr_read_sync(dev, NULL, 4096, NULL);
}
}
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
struct fm_state *fm2;
int dr_val;
if (do_exit) {
return;}
if (!ctx) {
return;}
fm2 = (struct fm_struct*)(ctx); // warning?
//full_demod(buf, len, fm2);
memcpy(fm2->buf, buf, len);
fm2->buf_len = len;
sem_getvalue(&data_ready, &dr_val);
if (!dr_val) {
sem_post(&data_ready);}
}
static void *demod_thread_fn(void *arg)
{
struct fm_state *fm2;
int r = 0;
fm2 = (struct fm_struct*)(arg); // warning?
while (!do_exit) {
sem_wait(&data_ready);
full_demod(fm2->buf, fm2->buf_len, fm2);
}
return 0;
}
int main(int argc, char **argv)
{
#ifndef _WIN32
@ -295,13 +325,13 @@ int main(int argc, char **argv)
int i, gain = -10; // tenths of a dB
uint8_t *buffer;
uint32_t dev_index = 0;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
int device_count;
char vendor[256], product[256], serial[256];
fm.freqs[0] = 100000000;
fm.sample_rate = DEFAULT_SAMPLE_RATE;
fm.squelch_level = 150;
fm.freq_len = 0;
sem_init(&data_ready, 0, 0);
#ifndef _WIN32
while ((opt = getopt(argc, argv, "d:f:g:s:b:l:E::")) != -1) {
switch (opt) {
@ -345,9 +375,9 @@ int main(int argc, char **argv)
fm.freq_len = 1;
filename = argv[5];
#endif
out_block_size = DEFAULT_BUF_LENGTH;
buffer = malloc(out_block_size * sizeof(uint8_t));
buffer = malloc(DEFAULT_BUF_LENGTH * sizeof(uint8_t));
//buffer = fm.buf;
device_count = rtlsdr_get_device_count();
if (!device_count) {
@ -406,9 +436,9 @@ int main(int argc, char **argv)
if (r < 0)
fprintf(stderr, "WARNING: Failed to reset buffers.\n");
fprintf(stderr, "Reading samples in async mode...\n");
r = rtlsdr_read_async(dev, rtlsdr_callback, (void *)(&fm),
DEFAULT_ASYNC_BUF_NUMBER, out_block_size);
pthread_create(&demod_thread, NULL, demod_thread_fn, (void *)(&fm));
rtlsdr_read_async(dev, rtlsdr_callback, (void *)(&fm),
DEFAULT_ASYNC_BUF_NUMBER, DEFAULT_BUF_LENGTH);
if (do_exit)
fprintf(stderr, "\nUser cancel, exiting...\n");