use rtl-sdr instead of USRP

Signed-off-by: Steve Markgraf <steve@steve-m.de>

AUTHORS

@@ -1,3 +1,3 @@
 Joshua Lackey <jl@thre.at>
 Alexander Chemeris <alexander.chemeris@gmail.com>
-
+Steve Markgraf <steve@steve-m.de>

README

@@ -5,3 +5,6 @@ offset.
 See http://thre.at/kalibrate 
 
 Copyright (c) 2010, Joshua Lackey (jl@thre.at)
+
+modified for use with rtl-sdr devices,
+Copyright (c) 2012, Steve Markgraf (steve@steve-m.de)

configure.ac

@@ -26,9 +26,9 @@ PKG_CHECK_MODULES(FFTW3, fftw3 >= 3.0)
 AC_SUBST(FFTW3_LIBS)
 AC_SUBST(FFTW3_CFLAGS)
 
-PKG_CHECK_MODULES(USRP, usrp >= 3.3)
+PKG_CHECK_MODULES(LIBRTLSDR, librtlsdr)
-AC_SUBST(USRP_LIBS)
+AC_SUBST(LIBRTLSDR_LIBS)
-AC_SUBST(USRP_CFLAGS)
+AC_SUBST(LIBRTLSDR_CFLAGS)
 
 # OSX doesn't support System V shared memory
 AC_CANONICAL_HOST

src/Makefile.am

@@ -19,5 +19,5 @@ kal_SOURCES = \
    util.h\
    version.h
 
-kal_CXXFLAGS = $(FFTW3_CFLAGS) $(USRP_CFLAGS)
+kal_CXXFLAGS = $(FFTW3_CFLAGS) $(LIBRTLSDR_CFLAGS)
-kal_LDADD = $(FFTW3_LIBS) $(USRP_LIBS)
+kal_LDADD = $(FFTW3_LIBS) $(LIBRTLSDR_LIBS)

src/kal.cc

@@ -67,7 +67,8 @@ int g_debug = 0;
 
 void usage(char *prog) {
 
-	printf("kalibrate v%s, Copyright (c) 2010, Joshua Lackey\n", kal_version_string);
+	printf("kalibrate v%s-rtl, Copyright (c) 2010, Joshua Lackey\n", kal_version_string);
+	printf("modified for use with rtl-sdr devices, Copyright (c) 2012, Steve Markgraf");
 	printf("\nUsage:\n");
 	printf("\tGSM Base Station Scan:\n");
 	printf("\t\t%s <-s band indicator> [options]\n", basename(prog));
@@ -80,10 +81,9 @@ void usage(char *prog) {
 	printf("\t-f\tfrequency of nearby GSM base station\n");
 	printf("\t-c\tchannel of nearby GSM base station\n");
 	printf("\t-b\tband indicator (GSM850, GSM900, EGSM, DCS, PCS)\n");
-	printf("\t-R\tside A (0) or B (1), defaults to B\n");
+	printf("\t-g\tgain in dB\n");
-	printf("\t-A\tantenna TX/RX (0) or RX2 (1), defaults to RX2\n");
+	printf("\t-d\trtl-sdr device index\n");
-	printf("\t-g\tgain as %% of range, defaults to 45%%\n");
+	printf("\t-e\tinitial frequency error in ppm\n");
-	printf("\t-F\tFPGA master clock frequency, defaults to 52MHz\n");
 	printf("\t-v\tverbose\n");
 	printf("\t-D\tenable debug messages\n");
 	printf("\t-h\thelp\n");
@@ -95,13 +95,14 @@ int main(int argc, char **argv) {
 
 	char *endptr;
 	int c, antenna = 1, bi = BI_NOT_DEFINED, chan = -1, bts_scan = 0;
-	unsigned int subdev = 1, decimation = 192;
+	int ppm_error = 0;
+	unsigned int subdev = 0, decimation = 192;
 	long int fpga_master_clock_freq = 52000000;
-	float gain = 0.45;
+	float gain = 0;
 	double freq = -1.0, fd;
 	usrp_source *u;
 
-	while((c = getopt(argc, argv, "f:c:s:b:R:A:g:F:vDh?")) != EOF) {
+	while((c = getopt(argc, argv, "f:c:s:b:R:A:g:e:d:vDh?")) != EOF) {
 		switch(c) {
 			case 'f':
 				freq = strtod(optarg, 0);
@@ -163,11 +164,7 @@ int main(int argc, char **argv) {
 				break;
 
 			case 'g':
-				gain = strtod(optarg, 0);
+				gain = strtof(optarg, 0) * 10;
-				if((gain > 1.0) && (gain <= 100.0))
-					gain /= 100.0;
-				if((gain < 0.0) || (1.0 < gain))
-					usage(argv[0]);
 				break;
 
 			case 'F':
@@ -181,6 +178,14 @@ int main(int argc, char **argv) {
 				}
 				break;
 
+			case 'e':
+				ppm_error = strtol(optarg, 0, 0);
+				break;
+
+			case 'd':
+				subdev = strtol(optarg, 0, 0);
+				break;
+
 			case 'v':
 				g_verbosity++;
 				break;
@@ -221,6 +226,7 @@ int main(int argc, char **argv) {
 		chan = freq_to_arfcn(freq, &bi);
 	}
 
+#if 0
 	// sanity check clock
 	if(fpga_master_clock_freq < 48000000) {
 		fprintf(stderr, "error: FPGA master clock too slow: %li\n", fpga_master_clock_freq);
@@ -230,7 +236,7 @@ int main(int argc, char **argv) {
 	// calculate decimation -- get as close to GSM rate as we can
 	fd = (double)fpga_master_clock_freq / GSM_RATE;
 	decimation = (unsigned int)fd;
-
+#endif
 	if(g_debug) {
 #ifdef D_HOST_OSX
 		printf("debug: Mac OS X version\n");
@@ -251,10 +257,19 @@ int main(int argc, char **argv) {
 		fprintf(stderr, "error: usrp_source::open\n");
 		return -1;
 	}
-	u->set_antenna(antenna);
+//	u->set_antenna(antenna);
-	if(!u->set_gain(gain)) {
+	if (gain != 0) {
-		fprintf(stderr, "error: usrp_source::set_gain\n");
+		if(!u->set_gain(gain)) {
-		return -1;
+			fprintf(stderr, "error: usrp_source::set_gain\n");
+			return -1;
+		}
+	}
+
+	if (ppm_error != 0) {
+		if(u->set_freq_correction(ppm_error) < 0) {
+			fprintf(stderr, "error: usrp_source::set_freq_correction\n");
+			return -1;
+		}
 	}
 
 	if(!bts_scan) {

src/offset.cc

@@ -46,6 +46,7 @@ int offset_detect(usrp_source *u) {
 	unsigned int s_len, b_len, consumed, count;
 	float offset = 0.0, min = 0.0, max = 0.0, avg_offset = 0.0,
 	   stddev = 0.0, sps, offsets[AVG_COUNT];
+	double total_ppm;
 	complex *cbuf;
 	fcch_detector *l;
 	circular_buffer *cb;
@@ -118,5 +119,8 @@ int offset_detect(usrp_source *u) {
 	printf("overruns: %u\n", overruns);
 	printf("not found: %u\n", notfound);
 
+	total_ppm = u->m_freq_corr - (avg_offset / u->m_center_freq) * 1000000;
+
+	printf("average absolute error: %.3f ppm\n", total_ppm);
 	return 0;
 }

src/usrp_source.cc

@@ -34,10 +34,6 @@
 #include <math.h>
 #include <complex>
 
-#include <usrp/usrp_standard.h>
-#include <usrp/usrp_subdev_spec.h>
-#include <usrp/usrp_dbid.h>
-
 #include "usrp_source.h"
 
 extern int g_verbosity;
@@ -49,8 +45,6 @@ usrp_source::usrp_source(float sample_rate, long int fpga_master_clock_freq) {
 	m_desired_sample_rate = sample_rate;
 	m_sample_rate = 0.0;
 	m_decimation = 0;
-	m_u_rx.reset();
-	m_db_rx.reset();
 	m_cb = new circular_buffer(CB_LEN, sizeof(complex), 0);
 
 	pthread_mutex_init(&m_u_mutex, 0);
@@ -61,8 +55,6 @@ usrp_source::usrp_source(unsigned int decimation, long int fpga_master_clock_fre
 
 	m_fpga_master_clock_freq = fpga_master_clock_freq;
 	m_sample_rate = 0.0;
-	m_u_rx.reset();
-	m_db_rx.reset();
 	m_cb = new circular_buffer(CB_LEN, sizeof(complex), 0);
 
 	pthread_mutex_init(&m_u_mutex, 0);
@@ -79,6 +71,7 @@ usrp_source::~usrp_source() {
 
 	stop();
 	delete m_cb;
+	rtlsdr_close(dev);
 	pthread_mutex_destroy(&m_u_mutex);
 }
 
@@ -86,10 +79,6 @@ usrp_source::~usrp_source() {
 void usrp_source::stop() {
 
 	pthread_mutex_lock(&m_u_mutex);
-	if(m_db_rx)
-		m_db_rx->set_enable(0);
-	if(m_u_rx)
-		m_u_rx->stop();
 	pthread_mutex_unlock(&m_u_mutex);
 }
 
@@ -97,10 +86,6 @@ void usrp_source::stop() {
 void usrp_source::start() {
 
 	pthread_mutex_lock(&m_u_mutex);
-	if(m_db_rx)
-		m_db_rx->set_enable(1);
-	if(m_u_rx)
-		m_u_rx->start();
 	pthread_mutex_unlock(&m_u_mutex);
 }
 
@@ -109,7 +94,7 @@ void usrp_source::calculate_decimation() {
 
 	float decimation_f;
 
-	decimation_f = (float)m_u_rx->fpga_master_clock_freq() / m_desired_sample_rate;
+//	decimation_f = (float)m_u_rx->fpga_master_clock_freq() / m_desired_sample_rate;
 	m_decimation = (unsigned int)round(decimation_f) & ~1;
 
 	if(m_decimation < 4)
@@ -128,31 +113,42 @@ float usrp_source::sample_rate() {
 
 int usrp_source::tune(double freq) {
 
-	int r;
+	int r = 0;
-	usrp_tune_result tr;
 
 	pthread_mutex_lock(&m_u_mutex);
-	r = m_u_rx->tune(0, m_db_rx, freq, &tr);
+	if (freq != m_center_freq) {
+		r = rtlsdr_set_center_freq(dev, (uint32_t)freq);
+//		fprintf(stderr, "Tuned to %i Hz.\n", (uint32_t)freq);
+		m_center_freq = freq;
+	}
+
 	pthread_mutex_unlock(&m_u_mutex);
 
-	return r;
+	return (r < 0) ? 0 : 1;
 }
 
+int usrp_source::set_freq_correction(int ppm) {
+	m_freq_corr = ppm;
+	return rtlsdr_set_freq_correction(dev, ppm);
+}
 
 bool usrp_source::set_antenna(int antenna) {
 
-	return m_db_rx->select_rx_antenna(antenna);
+	return 0;
 }
 
-
 bool usrp_source::set_gain(float gain) {
+	int r, g = gain * 10;
 
-	float min = m_db_rx->gain_min(), max = m_db_rx->gain_max();
+	/* Enable manual gain */
+	r = rtlsdr_set_tuner_gain_mode(dev, 1);
+	if (r < 0)
+		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
 
-	if((gain < 0.0) || (1.0 < gain))
+	fprintf(stderr, "Setting gain: %.1f dB\n", gain/10);
-		return false;
+	r = rtlsdr_set_tuner_gain(dev, g);
 
-	return m_db_rx->set_gain(min + gain * (max - min));
+	return (r < 0) ? 0 : 1;
 }
 
 
@@ -160,75 +156,73 @@ bool usrp_source::set_gain(float gain) {
  * open() should be called before multiple threads access usrp_source.
  */
 int usrp_source::open(unsigned int subdev) {
+	int i, r, device_count, count;
+	uint32_t dev_index = subdev;
+	uint32_t samp_rate = 270833;
 
-	int do_set_decim = 0;
+	m_sample_rate = 270833.002142;
-	usrp_subdev_spec ss(subdev, 0);
 
-	if(!m_u_rx) {
+	device_count = rtlsdr_get_device_count();
-		if(!m_decimation) {
+	if (!device_count) {
-			do_set_decim = 1;
+		fprintf(stderr, "No supported devices found.\n");
-			m_decimation = 4;
+		exit(1);
-		}
-		if(!(m_u_rx = usrp_standard_rx::make(0, m_decimation,
-		   NCHAN, INITIAL_MUX, usrp_standard_rx::FPGA_MODE_NORMAL,
-		   FUSB_BLOCK_SIZE, FUSB_NBLOCKS, FPGA_FILENAME()))) {
-			fprintf(stderr, "error: usrp_standard_rx::make: "
-			   "failed!\n");
-			return -1;
-		}
-		m_u_rx->set_fpga_master_clock_freq(m_fpga_master_clock_freq);
-		m_u_rx->stop();
-
-		if(do_set_decim) {
-			calculate_decimation();
-		}
-
-		m_u_rx->set_decim_rate(m_decimation);
-		m_sample_rate = (double)m_u_rx->fpga_master_clock_freq() / m_decimation;
-
-		if(g_verbosity > 1) {
-			fprintf(stderr, "FPGA clock : %ld\n", m_u_rx->fpga_master_clock_freq());
-			fprintf(stderr, "Decimation : %u\n", m_decimation);
-			fprintf(stderr, "Sample rate: %f\n", m_sample_rate);
-		}
-	}
-	if(!m_u_rx->is_valid(ss)) {
-		fprintf(stderr, "error: invalid daughterboard\n");
-		return -1;
-	}
-	if(!(m_db_rx = m_u_rx->selected_subdev(ss))) {
-		fprintf(stderr, "error: no daughterboard\n");
-		return -1;
 	}
 
-	m_u_rx->set_mux(m_u_rx->determine_rx_mux_value(ss));
+	fprintf(stderr, "Found %d device(s):\n", device_count);
+	for (i = 0; i < device_count; i++)
+		fprintf(stderr, "  %d:  %s\n", i, rtlsdr_get_device_name(i));
+	fprintf(stderr, "\n");
 
-	set_gain(0.45);
+	fprintf(stderr, "Using device %d: %s\n",
-	m_db_rx->select_rx_antenna(1); // this is a nop for most db
+		dev_index,
+		rtlsdr_get_device_name(dev_index));
+
+	r = rtlsdr_open(&dev, dev_index);
+	if (r < 0) {
+		fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
+		exit(1);
+	}
+
+	/* Set the sample rate */
+	r = rtlsdr_set_sample_rate(dev, samp_rate);
+	if (r < 0)
+		fprintf(stderr, "WARNING: Failed to set sample rate.\n");
+
+	/* Reset endpoint before we start reading from it (mandatory) */
+	r = rtlsdr_reset_buffer(dev);
+	if (r < 0)
+		fprintf(stderr, "WARNING: Failed to reset buffers.\n");
+
+//	r = rtlsdr_set_offset_tuning(dev, 1);
+//	if (r < 0)
+//		fprintf(stderr, "WARNING: Failed to enable offset tuning\n");
 
 	return 0;
 }
 
+#define USB_PACKET_SIZE		(2 * 16384)
+#define FLUSH_SIZE		512
 
-#define USB_PACKET_SIZE 512
 
 int usrp_source::fill(unsigned int num_samples, unsigned int *overrun_i) {
 
 	bool overrun;
 	unsigned char ubuf[USB_PACKET_SIZE];
-	short *s = (short *)ubuf;
 	unsigned int i, j, space, overruns = 0;
 	complex *c;
+	int n_read;
 
 	while((m_cb->data_available() < num_samples) && (m_cb->space_available() > 0)) {
 
 		// read one usb packet from the usrp
 		pthread_mutex_lock(&m_u_mutex);
-		if(m_u_rx->read(ubuf, sizeof(ubuf), &overrun) != sizeof(ubuf)) {
+
+		if (rtlsdr_read_sync(dev, ubuf, sizeof(ubuf), &n_read) < 0) {
 			pthread_mutex_unlock(&m_u_mutex);
 			fprintf(stderr, "error: usrp_standard_rx::read\n");
 			return -1;
 		}
+
 		pthread_mutex_unlock(&m_u_mutex);
 		if(overrun)
 			overruns++;
@@ -237,12 +231,11 @@ int usrp_source::fill(unsigned int num_samples, unsigned int *overrun_i) {
 		c = (complex *)m_cb->poke(&space);
 
 		// set space to number of complex items to copy
-		if(space > (USB_PACKET_SIZE >> 2))
+		space = n_read / 2;
-			space = USB_PACKET_SIZE >> 2;
 
 		// write data
 		for(i = 0, j = 0; i < space; i += 1, j += 2)
-			c[i] = complex(s[j], s[j + 1]);
+			c[i] = complex((ubuf[j] - 127) * 256, (ubuf[j + 1] - 127) * 256);
 
 		// update cb
 		m_cb->wrote(i);
@@ -290,7 +283,7 @@ circular_buffer *usrp_source::get_buffer() {
 int usrp_source::flush(unsigned int flush_count) {
 
 	m_cb->flush();
-	fill(flush_count * USB_PACKET_SIZE, 0);
+	fill(flush_count * FLUSH_SIZE, 0);
 	m_cb->flush();
 
 	return 0;

src/usrp_source.h

@@ -25,7 +25,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <usrp/usrp_standard.h>
+#include <rtl-sdr.h>
 
 #include "usrp_complex.h"
 #include "circular_buffer.h"
@@ -41,6 +41,7 @@ public:
 	int read(complex *buf, unsigned int num_samples, unsigned int *samples_read);
 	int fill(unsigned int num_samples, unsigned int *overrun);
 	int tune(double freq);
+	int set_freq_correction(int ppm);
 	bool set_antenna(int antenna);
 	bool set_gain(float gain);
 	void start();
@@ -53,11 +54,13 @@ public:
 	static const unsigned int side_A = 0;
 	static const unsigned int side_B = 1;
 
+	double			m_center_freq;
+	int			m_freq_corr;
+
 private:
 	void calculate_decimation();
 
-	usrp_standard_rx_sptr	m_u_rx;
+	rtlsdr_dev_t		*dev;
-	db_base_sptr		m_db_rx;
 
 	float			m_sample_rate;
 	float			m_desired_sample_rate;
@@ -74,7 +77,7 @@ private:
 	pthread_mutex_t		m_u_mutex;
 
 	static const unsigned int	FLUSH_COUNT	= 10;
-	static const unsigned int	CB_LEN		= (1 << 20);
+	static const unsigned int	CB_LEN		= (16 * 16384);
 	static const int		NCHAN		= 1;
 	static const int		INITIAL_MUX	= -1;
 	static const int		FUSB_BLOCK_SIZE	= 1024;