add new tool: rtl_power

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

4 files changed, 886 insertions, 2 deletions

diff --git a/configure.ac b/configure.ac
index ce47d89..d59d820 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,6 +42,9 @@ AC_CHECK_LIB(m, atan2, [LIBS="$LIBS -lm"])
 dnl libmath (for rtl_adsb)
 AC_CHECK_LIB(m, sqrt, [LIBS="$LIBS -lm"])
 
+dnl libmath (for rtl_power)
+AC_CHECK_LIB(m, atan2, [LIBS="$LIBS -lm"])
+
 dnl librealtime (for rtl_test)
 AC_CHECK_LIB(rt, clock_gettime, [LIBS="$LIBS -lrt"])
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7cd62c8..7bca10b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -73,7 +73,8 @@ add_executable(rtl_test rtl_test.c)
 add_executable(rtl_fm rtl_fm.c)
 add_executable(rtl_eeprom rtl_eeprom.c)
 add_executable(rtl_adsb rtl_adsb.c)
-set(INSTALL_TARGETS rtlsdr_shared rtlsdr_static rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb)
+add_executable(rtl_power rtl_power.c)
+set(INSTALL_TARGETS rtlsdr_shared rtlsdr_static rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb rtl_power)
 
 target_link_libraries(rtl_sdr rtlsdr_shared
     ${LIBUSB_LIBRARIES}
@@ -99,9 +100,14 @@ target_link_libraries(rtl_adsb rtlsdr_shared
     ${LIBUSB_LIBRARIES}
     ${CMAKE_THREAD_LIBS_INIT}
 )
+target_link_libraries(rtl_power rtlsdr_shared
+    ${LIBUSB_LIBRARIES}
+    ${CMAKE_THREAD_LIBS_INIT}
+)
 if(UNIX)
 target_link_libraries(rtl_fm m)
 target_link_libraries(rtl_adsb m)
+target_link_libraries(rtl_power m)
 if(APPLE)
     target_link_libraries(rtl_test m)
 else()
@@ -116,12 +122,14 @@ target_link_libraries(rtl_test libgetopt_static)
 target_link_libraries(rtl_fm libgetopt_static)
 target_link_libraries(rtl_eeprom libgetopt_static)
 target_link_libraries(rtl_adsb libgetopt_static)
+target_link_libraries(rtl_power libgetopt_static)
 set_property(TARGET rtl_sdr APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 set_property(TARGET rtl_tcp APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 set_property(TARGET rtl_test APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 set_property(TARGET rtl_fm APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 set_property(TARGET rtl_eeprom APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 set_property(TARGET rtl_adsb APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
+set_property(TARGET rtl_power APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
 endif()
 ########################################################################
 # Install built library files & utilities
diff --git a/src/Makefile.am b/src/Makefile.am
index 386d36b..91cb010 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -10,7 +10,7 @@ lib_LTLIBRARIES = librtlsdr.la
 librtlsdr_la_SOURCES = librtlsdr.c tuner_e4k.c tuner_fc0012.c tuner_fc0013.c tuner_fc2580.c tuner_r820t.c
 librtlsdr_la_LDFLAGS = -version-info $(LIBVERSION)
 
-bin_PROGRAMS         = rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb
+bin_PROGRAMS         = rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb rtl_power
 
 rtl_sdr_SOURCES      = rtl_sdr.c
 rtl_sdr_LDADD        = librtlsdr.la
@@ -29,3 +29,6 @@ rtl_eeprom_LDADD        = librtlsdr.la $(LIBM)
 
 rtl_adsb_SOURCES      = rtl_adsb.c
 rtl_adsb_LDADD        = librtlsdr.la $(LIBM)
+
+rtl_power_SOURCES     = rtl_power.c
+rtl_power_LDADD       = librtlsdr.la $(LIBM)
diff --git a/src/rtl_power.c b/src/rtl_power.c
new file mode 100644
index 0000000..58da95a
--- /dev/null
+++ b/src/rtl_power.c
@@ -0,0 +1,870 @@
+/*
+ * 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
+ * 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/>.
+ */
+
+
+/*
+ * rtl_power: general purpose FFT integrator
+ * -f low_freq:high_freq:max_bin_size
+ * -i seconds
+ * outputs CSV
+ * time, low, high, step, db, db, db ...
+ * db optional?  raw output might be better for noise correction
+ * todo:
+ *	threading
+ *	randomized hopping
+ *	noise correction
+ *	continuous IIR
+ *	general astronomy usefulness
+ *	multiple dongles
+ *	multiple FFT workers
+ *	fft bins smaller than 61Hz
+ *	bandwidths smaller than 1MHz
+ *	check edge cropping for off-by-one and rounding errors
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+
+#ifndef _WIN32
+#include <unistd.h>
+#else
+#include <Windows.h>
+#include <fcntl.h>
+#include <io.h>
+#include "getopt/getopt.h"
+#define usleep(x) Sleep(x/1000)
+#define round(x) (x > 0.0 ? floor(x + 0.5): ceil(x - 0.5))
+#endif
+
+#include <pthread.h>
+#include <libusb.h>
+
+#include "rtl-sdr.h"
+
+#define DEFAULT_SAMPLE_RATE		24000
+#define DEFAULT_ASYNC_BUF_NUMBER	32
+#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			(1<<12)
+
+static volatile int do_exit = 0;
+static rtlsdr_dev_t *dev = NULL;
+FILE *file;
+
+int16_t* Sinewave;
+double* power_table;
+int N_WAVE, LOG2_N_WAVE;
+int next_power;
+int16_t *fft_buf;
+int *window_coefs;
+
+struct tuning_state
+/* one per tuning range */
+{
+	int freq;
+	int rate;
+	int bin_e;
+	long *avg;  /* length == 2^bin_e */
+	int samples;
+	long mega_samples;
+	//pthread_rwlock_t avg_lock;
+	//pthread_mutex_t avg_mutex;
+	/* having the iq buffer here is wasteful, but will avoid contention */
+	uint8_t *buf8;
+	int buf_len;
+	//pthread_rwlock_t buf_lock;
+	//pthread_mutex_t buf_mutex;
+};
+
+/* 3000 is enough for 3GHz b/w worst case */
+#define MAX_TUNES	3000
+struct tuning_state tunes[MAX_TUNES];
+int tune_count = 0;
+
+void usage(void)
+{
+	fprintf(stderr,
+		"rtl_power, a simple FFT logger for RTL2832 based DVB-T receivers\n\n"
+		"Use:\trtl_power -f freq_range [-options] [filename]\n"
+		"\t-f lower:upper:bin_size [Hz]\n"
+		"\t (bin size is a maximum, smaller more convenient bins\n"
+		"\t  will be used.  valid range 61-2M)\n"
+		"\t[-i integration_interval (default: 10 seconds)]\n"
+		"\t (buggy if a full sweep takes longer than the interval)\n"
+		"\t[-1 enables single-shot mode (default: off)]\n"
+		"\t[-e exit_timer (default: off/0)]\n"
+		//"\t[-s avg/iir smoothing (default: avg)]\n"
+		//"\t[-t threads (default: 1)]\n"
+		"\t[-d device_index (default: 0)]\n"
+		"\t[-g tuner_gain (default: automatic)]\n"
+		"\t[-p ppm_error (default: 0)]\n"
+		"\tfilename (a '-' dumps samples to stdout)\n"
+		"\t (omitting the filename also uses stdout)\n"
+		"\n"
+		"Experimental options:\n"
+		"\t[-w window (default: rectangle)]\n"
+		"\t (hamming, blackman, blackman-harris, hann-poisson, bartlett, youssef)\n"
+		// kaiser
+		"\t[-c crop_percent (default: 0%, recommended: 20%%-50%%)]\n"
+		"\t (discards data at the edges, 100%% discards everything)\n"
+		"\t (has no effect in rms bin mode)\n"
+		"\n"
+		"CSV FFT output columns:\n"
+		"\tdate, time, Hz low, Hz high, Hz step, samples, dbm, dbm, ...\n\n"
+		"Examples:\n"
+		"\trtl_power -f 88M:108M:125k fm_stations.csv\n"
+		"\t (creates 160 bins across the FM band,\n"
+		"\t  individual stations should be visible)\n"
+		"\trtl_power -f 100M:1G:1M -i 5m -1 survey.csv\n"
+		"\t (a five minute low res scan of nearly everything)\n"
+		"\trtl_power -f ... -i 15m -1 log.csv\n"
+		"\t (integrate for 15 minutes and exit afterwards)\n"
+		"\trtl_power -f ... -e 1h | gzip > log.csv.gz\n"
+		"\t (collect data for one hour and compress it on the fly)\n"
+		"Convert CSV to a waterfall graphic with\n"
+		"\thttp://kmkeen.com/tmp/heatmap.py.txt\n"
+		"");
+	exit(1);
+}
+
+#ifdef _WIN32
+BOOL WINAPI
+sighandler(int signum)
+{
+	if (CTRL_C_EVENT == signum) {
+		fprintf(stderr, "Signal caught, exiting!\n");
+		do_exit = 1;
+		return TRUE;
+	}
+	return FALSE;
+}
+#else
+static void sighandler(int signum)
+{
+	fprintf(stderr, "Signal caught, exiting!\n");
+	do_exit = 1;
+}
+#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)
+
+/* FFT based on fix_fft.c by Roberts, Slaney and Bouras
+   http://www.jjj.de/fft/fftpage.html
+   16 bit ints for everything
+   -32768..+32768 maps to -1.0..+1.0
+*/
+
+void sine_table(int size)
+{
+	int i;
+	double d;
+	LOG2_N_WAVE = size;
+	N_WAVE = 1 << LOG2_N_WAVE;
+	Sinewave = malloc(sizeof(int16_t) * N_WAVE*3/4);
+	power_table = malloc(sizeof(double) * N_WAVE);
+	for (i=0; i<N_WAVE*3/4; i++)
+	{
+		d = (double)i * 2.0 * M_PI / N_WAVE;
+		Sinewave[i] = (int)round(32767*sin(d));
+		//printf("%i\n", Sinewave[i]);
+	}
+}
+
+inline int16_t FIX_MPY(int16_t a, int16_t b)
+/* fixed point multiply and scale */
+{
+	int c = ((int)a * (int)b) >> 14;
+	b = c & 0x01;
+	return (c >> 1) + b;
+}
+
+int fix_fft(int16_t iq[], int16_t m)
+/* interleaved iq[], 0 <= n < 2**m, changes in place */
+{
+	int mr, nn, i, j, l, k, istep, n, shift;
+	int16_t qr, qi, tr, ti, wr, wi;
+	n = 1 << m;
+	if (n > N_WAVE)
+		{return -1;}
+	mr = 0;
+	nn = n - 1;
+	/* decimation in time - re-order data */
+	for (m=1; m<=nn; ++m) {
+		l = n;
+		do
+			{l >>= 1;}
+		while (mr+l > nn);
+		mr = (mr & (l-1)) + l;
+		if (mr <= m)
+			{continue;}
+		// real = 2*m, imag = 2*m+1
+		tr = iq[2*m];
+		iq[2*m] = iq[2*mr];
+		iq[2*mr] = tr;
+		ti = iq[2*m+1];
+		iq[2*m+1] = iq[2*mr+1];
+		iq[2*mr+1] = ti;
+	}
+	l = 1;
+	k = LOG2_N_WAVE-1;
+	while (l < n) {
+		shift = 1;
+		istep = l << 1;
+		for (m=0; m<l; ++m) {
+			j = m << k;
+			wr =  Sinewave[j+N_WAVE/4];
+			wi = -Sinewave[j];
+			if (shift) {
+				wr >>= 1; wi >>= 1;}
+			for (i=m; i<n; i+=istep) {
+				j = i + l;
+				tr = FIX_MPY(wr,iq[2*j]) - FIX_MPY(wi,iq[2*j+1]);
+				ti = FIX_MPY(wr,iq[2*j+1]) + FIX_MPY(wi,iq[2*j]);
+				qr = iq[2*i];
+				qi = iq[2*i+1];
+				if (shift) {
+					qr >>= 1; qi >>= 1;}
+				iq[2*j] = qr - tr;
+				iq[2*j+1] = qi - ti;
+				iq[2*i] = qr + tr;
+				iq[2*i+1] = qi + ti;
+			}
+		}
+		--k;
+		l = istep;
+	}
+	return 0;
+}
+
+double rectangle(int i, int length)
+{
+	return 1.0;
+}
+
+double hamming(int i, int length)
+{
+	double a, b, w, N1;
+	a = 25.0/46.0;
+	b = 21.0/46.0;
+	N1 = (double)(length-1);
+	w = a - b*cos(2*i*M_PI/N1);
+	return w;
+}
+
+double blackman(int i, int length)
+{
+	double a0, a1, a2, w, N1;
+	a0 = 7938.0/18608.0;
+	a1 = 9240.0/18608.0;
+	a2 = 1430.0/18608.0;
+	N1 = (double)(length-1);
+	w = a0 - a1*cos(2*i*M_PI/N1) + a2*cos(4*i*M_PI/N1);
+	return w;
+}
+
+double blackman_harris(int i, int length)
+{
+	double a0, a1, a2, a3, w, N1;
+	a0 = 0.35875;
+	a1 = 0.48829;
+	a2 = 0.14128;
+	a3 = 0.01168;
+	N1 = (double)(length-1);
+	w = a0 - a1*cos(2*i*M_PI/N1) + a2*cos(4*i*M_PI/N1) - a3*cos(6*i*M_PI/N1);
+	return w;
+}
+
+double hann_poisson(int i, int length)
+{
+	double a, N1, w;
+	a = 2.0;
+	N1 = (double)(length-1);
+	w = 0.5 * (1 - cos(2*M_PI*i/N1)) * \
+	    pow(M_E, (-a*(double)abs((int)(N1-1-2*i)))/N1);
+	return w;
+}
+
+double youssef(int i, int length)
+/* really a blackman-harris-poisson window, but that is a mouthful */
+{
+	double a, a0, a1, a2, a3, w, N1;
+	a0 = 0.35875;
+	a1 = 0.48829;
+	a2 = 0.14128;
+	a3 = 0.01168;
+	N1 = (double)(length-1);
+	w = a0 - a1*cos(2*i*M_PI/N1) + a2*cos(4*i*M_PI/N1) - a3*cos(6*i*M_PI/N1);
+	a = 0.0025;
+	w *= pow(M_E, (-a*(double)abs((int)(N1-1-2*i)))/N1);
+	return w;
+}
+
+double kaiser(int i, int length)
+// todo, become more smart
+{
+	return 1.0;
+}
+
+double bartlett(int i, int length)
+{
+	double N1, L, w;
+	L = (double)length;
+	N1 = L - 1;
+	w = (i - N1/2) / (L/2);
+	if (w < 0) {
+		w = -w;}
+	w = 1 - w;
+	return w;
+}
+
+void rms_power(struct tuning_state *ts)
+/* for bins between 1MHz and 2MHz */
+{
+	int i, s;
+	uint8_t *buf = ts->buf8;
+	int buf_len = ts->buf_len;
+	long p, t;
+	int ln, lp;
+	double dc, err;
+
+	p = t = 0L;
+	for (i=0; i<buf_len; i++) {
+		s = (int)buf[i] - 127;
+		t += (long)s;
+		p += (long)(s * s);
+	}
+	/* correct for dc offset in squares */
+	dc = (double)t / (double)buf_len;
+	err = t * 2 * dc - dc * dc * buf_len;
+	p -= (long)round(err);
+
+	ts->avg[0] += p;
+	ts->samples += 1;
+	/* complex pairs, half length */
+	ts->mega_samples += (long)(buf_len/2);
+}
+
+double atofs(char *f)
+/* standard suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(f);
+	last = f[len-1];
+	f[len-1] = '\0';
+	switch (last) {
+		case 'g':
+		case 'G':
+			suff *= 1e3;
+		case 'm':
+		case 'M':
+			suff *= 1e3;
+		case 'k':
+		case 'K':
+			suff *= 1e3;
+			suff *= atof(f);
+			f[len-1] = last;
+			return suff;
+	}
+	f[len-1] = last;
+	return atof(f);
+}
+
+double atoft(char *f)
+/* time suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(f);
+	last = f[len-1];
+	f[len-1] = '\0';
+	switch (last) {
+		case 'h':
+		case 'H':
+			suff *= 60;
+		case 'm':
+		case 'M':
+			suff *= 60;
+		case 's':
+		case 'S':
+			suff *= atof(f);
+			f[len-1] = last;
+			return suff;
+	}
+	f[len-1] = last;
+	return atof(f);
+}
+
+double atofp(char *f)
+/* percent suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(f);
+	last = f[len-1];
+	f[len-1] = '\0';
+	switch (last) {
+		case '%':
+			suff *= 0.01;
+			suff *= atof(f);
+			f[len-1] = last;
+			return suff;
+	}
+	f[len-1] = last;
+	return atof(f);
+}
+
+int nearest_gain(int target_gain)
+{
+	int i, err1, err2, count, close_gain;
+	int* gains;
+	count = rtlsdr_get_tuner_gains(dev, NULL);
+	if (count <= 0) {
+		return 0;
+	}
+	gains = malloc(sizeof(int) * count);
+	count = rtlsdr_get_tuner_gains(dev, gains);
+	close_gain = gains[0];
+	for (i=0; i<count; i++) {
+		err1 = abs(target_gain - close_gain);
+		err2 = abs(target_gain - gains[i]);
+		if (err2 < err1) {
+			close_gain = gains[i];
+		}
+	}
+	free(gains);
+	return close_gain;
+}
+
+void frequency_range(char *arg, double crop)
+/* flesh out the tunes[] for scanning */
+// do we want the fewest ranges (easy) or the fewest bins (harder)?
+{
+	char *start, *stop, *step;
+	int i, j, upper, lower, max_size, bw_seen, bw_used, bin_size, bin_e, buf_len;
+	struct tuning_state *ts;
+	/* hacky string parsing */
+	start = arg;
+	stop = strchr(start, ':') + 1;
+	stop[-1] = '\0';
+	step = strchr(stop, ':') + 1;
+	step[-1] = '\0';
+	lower = (int)atofs(start);
+	upper = (int)atofs(stop);
+	max_size = (int)atofs(step);
+	stop[-1] = ':';
+	step[-1] = ':';
+	/* evenly sized ranges, as close to 2MHz as possible */
+	for (i=1; i<1500; i++) {
+		bw_seen = (upper - lower) / i;
+		bw_used = (int)((double)(bw_seen) / (1.0 - crop));
+		if (bw_used > 2000000) {
+			continue;}
+		tune_count = i;
+		break;
+	}
+	/* number of bins is power-of-two, bin size is under limit */
+	for (i=1; i<=21; i++) {
+		bin_e = i;
+		bin_size = bw_used / (1<<i);
+		if (bin_size <= max_size) {
+			break;}
+	}
+	/* unless giant bins */
+	if (max_size >= 1000000) {
+		bw_seen = max_size;
+		bw_used = max_size;
+		tune_count = (upper - lower) / bw_seen;
+		bin_e = 0;
+	}
+	if (tune_count > MAX_TUNES) {
+		fprintf(stderr, "Error: bandwidth too wide.\n");
+		exit(1);
+	}
+	buf_len = DEFAULT_BUF_LENGTH;
+	if ((2<<bin_e) > buf_len) {
+		buf_len = (2<<bin_e);
+	}
+	/* build the array */
+	for (i=0; i<tune_count; i++) {
+		ts = &tunes[i];
+		ts->freq = lower + i*bw_seen + bw_seen/2;
+		ts->rate = bw_used;
+		ts->bin_e = bin_e;
+		ts->samples = 0;
+		ts->mega_samples = 0L;
+		ts->avg = (long*)malloc((1<<bin_e) * sizeof(long));
+		if (!ts->avg) {
+			fprintf(stderr, "Error: malloc.\n");
+			exit(1);
+		}
+		for (j=0; j<(1<<bin_e); j++) {
+			ts->avg[j] = 0L;
+		}
+		ts->buf8 = (uint8_t*)malloc(buf_len * sizeof(uint8_t));
+		if (!ts->buf8) {
+			fprintf(stderr, "Error: malloc.\n");
+			exit(1);
+		}
+		ts->buf_len = buf_len;
+	}
+	/* report */
+	fprintf(stderr, "Number of frequency hops: %i\n", tune_count);
+	fprintf(stderr, "Dongle bandwidth: %iHz\n", bw_used);
+	fprintf(stderr, "Total FFT bins: %i\n", tune_count * (1<<bin_e));
+	fprintf(stderr, "Logged FFT bins: %i\n", \
+	  (int)((double)(tune_count * (1<<bin_e)) * (1.0-crop)));
+	fprintf(stderr, "FFT bin size: %iHz\n", bin_size);
+	fprintf(stderr, "Buffer size: %0.2fms\n", 1000 * 0.5 * (float)buf_len / (float)bw_used);
+}
+
+void retune(rtlsdr_dev_t *d, int freq)
+{
+	uint8_t dump[BUFFER_DUMP];
+	int n_read;
+	rtlsdr_set_center_freq(d, (uint32_t)freq);
+	/* wait for settling and flush buffer */
+	usleep(5000);
+	rtlsdr_read_sync(d, &dump, BUFFER_DUMP, &n_read);
+	if (n_read != BUFFER_DUMP) {
+		fprintf(stderr, "Error: bad retune.\n");}
+}
+
+void scanner(void)
+{
+	int i, j, f, n_read, offset, bin_e, bin_len, buf_len;
+	struct tuning_state *ts;
+	bin_e = tunes[0].bin_e;
+	bin_len = 1 << bin_e;
+	buf_len = tunes[0].buf_len;
+	for (i=0; i<tune_count; i++) {
+		if (do_exit) {
+			break;}
+		ts = &tunes[i];
+		f = (int)rtlsdr_get_center_freq(dev);
+		if (f != ts->freq) {
+			retune(dev, ts->freq);}
+		rtlsdr_read_sync(dev, ts->buf8, buf_len, &n_read);
+		if (n_read != buf_len) {
+			fprintf(stderr, "Error: dropped samples.\n");}
+		/* rms */
+		if (bin_len == 1) {
+			rms_power(ts);
+			continue;
+		}
+		/* fft */
+		for (j=0; j<buf_len; j++) {
+			fft_buf[j] = (int16_t)ts->buf8[j] - 127;
+		}
+		for (offset=0; offset<buf_len; offset+=(2*bin_len)) {
+			// todo, let rect skip this
+			for (j=0; j<bin_len; j++) {
+				fft_buf[offset+j*2]   *= window_coefs[j];
+				fft_buf[offset+j*2+1] *= window_coefs[j];
+			}
+			fix_fft(fft_buf+offset, bin_e);
+			for (j=0; j<bin_len; j++) {
+				ts->avg[j] += (long) abs(fft_buf[offset+j*2]);
+			}
+			ts->samples += 1;
+		}
+	}
+}
+
+void csv_dbm(struct tuning_state *ts, double crop)
+{
+	int i, len, i1, i2, bw2;
+	long tmp;
+	double dbm;
+	len = 1 << ts->bin_e;
+	/* fix FFT stuff quirks */
+	if (ts->bin_e > 0) {
+		/* nuke DC component (not effective for all windows) */
+		ts->avg[0] = ts->avg[1];
+		/* FFT is translated by 180 degrees */
+		for (i=0; i<len/2; i++) {
+			tmp = ts->avg[i];
+			ts->avg[i] = ts->avg[i+len/2];
+			ts->avg[i+len/2] = tmp;
+		}
+	}
+	/* Hz low, Hz high, Hz step, samples, dbm, dbm, ... */
+	bw2 = (int)((double)ts->rate * (1.0-crop) * 0.5);
+	fprintf(file, "%i, %i, %.2f, %i, ", ts->freq - bw2, ts->freq + bw2,
+		(double)ts->rate / (double)len, ts->samples);
+	// something seems off with the dbm math
+	i1 = 0 + (int)((double)len * crop * 0.5);
+	i2 = (len-1) - (int)((double)len * crop * 0.5);
+	for (i=i1; i<i2; i++) {
+		dbm  = (double)ts->avg[i];
+		dbm /= (double)ts->rate;
+		dbm /= (double)ts->samples;
+		dbm  = 10 * log10(dbm);
+		fprintf(file, "%.2f, ", dbm);
+	}
+	dbm = (double)ts->avg[i2] / ((double)ts->rate * (double)ts->samples);
+	if (ts->bin_e == 0) {
+		dbm = ((double)ts->avg[0] / \
+		((double)ts->rate * (double)ts->samples));}
+	dbm  = 10 * log10(dbm);
+	fprintf(file, "%.2f\n", dbm);
+	for (i=0; i<len; i++) {
+		ts->avg[i] = 0L;
+	}
+	ts->samples = 0;
+	ts->mega_samples = 0L;
+}
+
+int main(int argc, char **argv)
+{
+#ifndef _WIN32
+	struct sigaction sigact;
+#endif
+	char *filename = NULL;
+	int i, length, n_read, r, opt, wb_mode = 0;
+	int gain = AUTO_GAIN; // tenths of a dB
+	uint8_t *buffer;
+	uint32_t dev_index = 0;
+	int device_count;
+	int ppm_error = 0;
+	int interval = 10;
+	int fft_threads = 1;
+	int smoothing = 0;
+	int single = 0;
+	double crop = 0.1;
+	char vendor[256], product[256], serial[256];
+	char *freq_optarg;
+	time_t next_tick;
+	time_t time_now;
+	time_t exit_time = 0;
+	char t_str[50];
+	struct tm *cal_time;
+	double (*window_fn)(int, int) = rectangle;
+
+	while ((opt = getopt(argc, argv, "f:i:s:t:d:g:p:e:w:c:1h")) != -1) {
+		switch (opt) {
+		case 'f': // lower:upper:bin_size
+			freq_optarg = strdup(optarg);
+			break;
+		case 'd':
+			dev_index = atoi(optarg);
+			break;
+		case 'g':
+			gain = (int)(atof(optarg) * 10);
+			break;
+		case 'c':
+			crop = atofp(optarg);
+			break;
+		case 'i':
+			interval = (int)round(atoft(optarg));
+			break;
+		case 'e':
+			exit_time = (time_t)((int)round(atoft(optarg)));
+			break;
+		case 's':
+			if (strcmp("avg",  optarg) == 0) {
+				smoothing = 0;}
+			if (strcmp("iir",  optarg) == 0) {
+				smoothing = 1;}
+			break;
+		case 'w':
+			if (strcmp("rectangle",  optarg) == 0) {
+				window_fn = rectangle;}
+			if (strcmp("hamming",  optarg) == 0) {
+				window_fn = hamming;}
+			if (strcmp("blackman",  optarg) == 0) {
+				window_fn = blackman;}
+			if (strcmp("blackman-harris",  optarg) == 0) {
+				window_fn = blackman_harris;}
+			if (strcmp("hann-poisson",  optarg) == 0) {
+				window_fn = hann_poisson;}
+			if (strcmp("youssef",  optarg) == 0) {
+				window_fn = youssef;}
+			if (strcmp("kaiser",  optarg) == 0) {
+				window_fn = kaiser;}
+			if (strcmp("bartlett",  optarg) == 0) {
+				window_fn = bartlett;}
+			break;
+		case 't':
+			fft_threads = atoi(optarg);
+			break;
+		case 'p':
+			ppm_error = atoi(optarg);
+			break;
+		case '1':
+			single = 1;
+			break;
+		case 'h':
+		default:
+			usage();
+			break;
+		}
+	}
+
+	frequency_range(freq_optarg, crop);
+
+	if (tune_count == 0) {
+		usage();}
+
+	if (argc <= optind) {
+		filename = "-";
+	} else {
+		filename = argv[optind];
+	}
+
+	if (interval < 1) {
+		interval = 1;}
+
+	fprintf(stderr, "Reporting every %i seconds\n", interval);
+
+	device_count = rtlsdr_get_device_count();
+	if (!device_count) {
+		fprintf(stderr, "No supported devices found.\n");
+		exit(1);
+	}
+
+	fprintf(stderr, "Found %d device(s):\n", device_count);
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		fprintf(stderr, "  %d:  %s, %s, SN: %s\n", i, vendor, product, serial);
+	}
+	fprintf(stderr, "\n");
+
+	fprintf(stderr, "Using device %d: %s\n",
+		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);
+	}
+#ifndef _WIN32
+	sigact.sa_handler = sighandler;
+	sigemptyset(&sigact.sa_mask);
+	sigact.sa_flags = 0;
+	sigaction(SIGINT, &sigact, NULL);
+	sigaction(SIGTERM, &sigact, NULL);
+	sigaction(SIGQUIT, &sigact, NULL);
+	sigaction(SIGPIPE, &sigact, NULL);
+#else
+	SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
+#endif
+
+	/* Set the tuner gain */
+	if (gain == AUTO_GAIN) {
+		r = rtlsdr_set_tuner_gain_mode(dev, 0);
+	} else {
+		r = rtlsdr_set_tuner_gain_mode(dev, 1);
+		gain = nearest_gain(gain);
+		r = rtlsdr_set_tuner_gain(dev, gain);
+	}
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
+	} else if (gain == AUTO_GAIN) {
+		fprintf(stderr, "Tuner gain set to automatic.\n");
+	} else {
+		fprintf(stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
+	}
+	r = rtlsdr_set_freq_correction(dev, ppm_error);
+
+	if (strcmp(filename, "-") == 0) { /* Write log to stdout */
+		file = stdout;
+#ifdef _WIN32
+		_setmode(_fileno(file), _O_BINARY);
+#endif
+	} else {
+		file = fopen(filename, "wb");
+		if (!file) {
+			fprintf(stderr, "Failed to open %s\n", filename);
+			exit(1);
+		}
+	}
+
+	/* 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");}
+
+	/* actually do stuff */
+	rtlsdr_set_sample_rate(dev, (uint32_t)tunes[0].rate);
+	sine_table(tunes[0].bin_e);
+	next_tick = time(NULL) + interval;
+	if (exit_time) {
+		exit_time = time(NULL) + exit_time;}
+	fft_buf = malloc(tunes[0].buf_len * sizeof(int16_t));
+	length = 1 << tunes[0].bin_e;
+	window_coefs = malloc(length * sizeof(int));
+	for (i=0; i<length; i++) {
+		window_coefs[i] = (int)(256*window_fn(i, length));
+	}
+	while (!do_exit) {
+		scanner();
+		time_now = time(NULL);
+		if (time_now <= next_tick) {
+			continue;}
+		// time, Hz low, Hz high, Hz step, samples, dbm, dbm, ...
+		cal_time = localtime(&time_now);
+		strftime(t_str, 50, "%Y-%m-%d, %H:%M:%S", cal_time);
+		for (i=0; i<tune_count; i++) {
+			fprintf(file, "%s, ", t_str);
+			csv_dbm(&tunes[i], crop);
+		}
+		fflush(file);
+		while (time(NULL) >= next_tick) {
+			next_tick += interval;}
+		if (single) {
+			do_exit = 1;}
+		if (exit_time && time(NULL) >= exit_time) {
+			do_exit = 1;}
+	}
+
+	/* clean up */
+
+	if (do_exit) {
+		fprintf(stderr, "\nUser cancel, exiting...\n");}
+	else {
+		fprintf(stderr, "\nLibrary error %d, exiting...\n", r);}
+
+	if (file != stdout) {
+		fclose(file);}
+
+	rtlsdr_close(dev);
+	free(fft_buf);
+	free(window_coefs);
+	//for (i=0; i<tune_count; i++) {
+	//	free(tunes[i].avg);
+	//	free(tunes[i].buf8);
+	//}
+	return r >= 0 ? r : -r;
+}
+
+// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab