Merge pull request #353 from mossmann/ifft

IFFT

host/hackrf-tools/src/hackrf_sweep.c

@@ -108,6 +108,7 @@ int gettimeofday(struct timeval *tv, void* ignored) {
 uint32_t num_samples = SAMPLES_PER_BLOCK;
 int num_ranges = 0;
 uint16_t frequencies[MAX_SWEEP_RANGES*2];
+int step_count;
 
 static float TimevalDiff(const struct timeval *a, const struct timeval *b) {
    return (a->tv_sec - b->tv_sec) + 1e-6f * (a->tv_usec - b->tv_usec);
@@ -163,6 +164,7 @@ volatile bool do_exit = false;
 
 FILE* fd = NULL;
 volatile uint32_t byte_count = 0;
+volatile uint64_t sweep_count = 0;
 
 struct timeval time_start;
 struct timeval t_start;
@@ -175,6 +177,7 @@ bool antenna = false;
 uint32_t antenna_enable;
 
 bool binary_output = false;
+bool ifft_output = false;
 bool one_shot = false;
 volatile bool sweep_started = false;
 
@@ -183,6 +186,10 @@ double fft_bin_width;
 fftwf_complex *fftwIn = NULL;
 fftwf_complex *fftwOut = NULL;
 fftwf_plan fftwPlan = NULL;
+fftwf_complex *ifftwIn = NULL;
+fftwf_complex *ifftwOut = NULL;
+fftwf_plan ifftwPlan = NULL;
+uint32_t ifft_idx = 0;
 float* pwr;
 float* window;
 
@@ -200,7 +207,7 @@ int rx_callback(hackrf_transfer* transfer) {
 	uint64_t frequency; /* in Hz */
 	uint64_t band_edge;
 	uint32_t record_length;
-	int i, j;
+	int i, j, ifft_bins;
 	struct tm *fft_time;
 	char time_str[50];
 	struct timeval usb_transfer_time;
@@ -212,6 +219,7 @@ int rx_callback(hackrf_transfer* transfer) {
 	gettimeofday(&usb_transfer_time, NULL);
 	byte_count += transfer->valid_length;
 	buf = (int8_t*) transfer->buffer;
+	ifft_bins = fftSize * step_count;
 	for(j=0; j<BLOCKS_PER_TRANSFER; j++) {
 		ubuf = (uint8_t*) buf;
 		if(ubuf[0] == 0x7F && ubuf[1] == 0x7F) {
@@ -223,8 +231,20 @@ int rx_callback(hackrf_transfer* transfer) {
 			continue;
 		}
 		if (frequency == (uint64_t)(FREQ_ONE_MHZ*frequencies[0])) {
-			if(one_shot && sweep_started) {
+			if(sweep_started) {
-				do_exit = true;
+				if(ifft_output) {
+					fftwf_execute(ifftwPlan);
+					for(i=0; i < ifft_bins; i++) {
+						ifftwOut[i][0] *= 1.0f / ifft_bins;
+						ifftwOut[i][1] *= 1.0f / ifft_bins;
+						fwrite(&ifftwOut[i][0], sizeof(float), 1, fd);
+						fwrite(&ifftwOut[i][1], sizeof(float), 1, fd);
+					}
+				}
+				sweep_count++;
+				if(one_shot) {
+					do_exit = true;
+				}
 			}
 			sweep_started = true;
 			time_stamp = usb_transfer_time;
@@ -262,19 +282,33 @@ int rx_callback(hackrf_transfer* transfer) {
 			record_length = 2 * sizeof(band_edge)
 					+ (fftSize/4) * sizeof(float);
 
-			fwrite(&record_length, sizeof(record_length), 1, stdout);
+			fwrite(&record_length, sizeof(record_length), 1, fd);
 			band_edge = frequency;
-			fwrite(&band_edge, sizeof(band_edge), 1, stdout);
+			fwrite(&band_edge, sizeof(band_edge), 1, fd);
 			band_edge = frequency + DEFAULT_SAMPLE_RATE_HZ / 4;
-			fwrite(&band_edge, sizeof(band_edge), 1, stdout);
+			fwrite(&band_edge, sizeof(band_edge), 1, fd);
-			fwrite(&pwr[1+(fftSize*5)/8], sizeof(float), fftSize/4, stdout);
+			fwrite(&pwr[1+(fftSize*5)/8], sizeof(float), fftSize/4, fd);
 
-			fwrite(&record_length, sizeof(record_length), 1, stdout);
+			fwrite(&record_length, sizeof(record_length), 1, fd);
 			band_edge = frequency + DEFAULT_SAMPLE_RATE_HZ / 2;
-			fwrite(&band_edge, sizeof(band_edge), 1, stdout);
+			fwrite(&band_edge, sizeof(band_edge), 1, fd);
 			band_edge = frequency + (DEFAULT_SAMPLE_RATE_HZ * 3) / 4;
-			fwrite(&band_edge, sizeof(band_edge), 1, stdout);
+			fwrite(&band_edge, sizeof(band_edge), 1, fd);
-			fwrite(&pwr[1+fftSize/8], sizeof(float), fftSize/4, stdout);
+			fwrite(&pwr[1+fftSize/8], sizeof(float), fftSize/4, fd);
+		} else if(ifft_output) {
+			ifft_idx = round((frequency - (uint64_t)(FREQ_ONE_MHZ*frequencies[0]))
+					/ fft_bin_width);
+			ifft_idx = (ifft_idx + ifft_bins/2) % ifft_bins;
+			for(i = 0; (fftSize / 4) > i; i++) {
+				ifftwIn[ifft_idx + i][0] = fftwOut[i + 1 + (fftSize*5)/8][0];
+				ifftwIn[ifft_idx + i][1] = fftwOut[i + 1 + (fftSize*5)/8][1];
+			}
+			ifft_idx += fftSize / 2;
+			ifft_idx %= ifft_bins;
+			for(i = 0; (fftSize / 4) > i; i++) {
+				ifftwIn[ifft_idx + i][0] = fftwOut[i + 1 + (fftSize/8)][0];
+				ifftwIn[ifft_idx + i][1] = fftwOut[i + 1 + (fftSize/8)][1];
+			}
 		} else {
 			fft_time = localtime(&time_stamp.tv_sec);
 			strftime(time_str, 50, "%Y-%m-%d, %H:%M:%S", fft_time);
@@ -285,8 +319,8 @@ int rx_callback(hackrf_transfer* transfer) {
 					(uint64_t)(frequency+DEFAULT_SAMPLE_RATE_HZ/4),
 					fft_bin_width,
 					fftSize);
-			for(i=1+(fftSize*5)/8; (1+(fftSize*7)/8) > i; i++) {
+			for(i = 0; (fftSize / 4) > i; i++) {
-				fprintf(fd, ", %.2f", pwr[i]);
+				fprintf(fd, ", %.2f", pwr[i + 1 + (fftSize*5)/8]);
 			}
 			fprintf(fd, "\n");
 			fprintf(fd, "%s.%06ld, %" PRIu64 ", %" PRIu64 ", %.2f, %u",
@@ -296,8 +330,8 @@ int rx_callback(hackrf_transfer* transfer) {
 					(uint64_t)(frequency+((DEFAULT_SAMPLE_RATE_HZ*3)/4)),
 					fft_bin_width,
 					fftSize);
-			for(i=1+fftSize/8; (1+(fftSize*3)/8) > i; i++) {
+			for(i = 0; (fftSize / 4) > i; i++) {
-				fprintf(fd, ", %.2f", pwr[i]);
+				fprintf(fd, ", %.2f", pwr[i + 1 + (fftSize/8)]);
 			}
 			fprintf(fd, "\n");
 		}
@@ -318,7 +352,8 @@ static void usage() {
 	fprintf(stderr, "\t[-w bin_width] # FFT bin width (frequency resolution) in Hz\n");
 	fprintf(stderr, "\t[-1] # one shot mode\n");
 	fprintf(stderr, "\t[-B] # binary output\n");
-	fprintf(stderr, "\t-r filename # output file");
+	fprintf(stderr, "\t[-I] # binary inverse FFT output\n");
+	fprintf(stderr, "\t-r filename # output file\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "Output fields:\n");
 	fprintf(stderr, "\tdate, time, hz_low, hz_high, hz_bin_width, num_samples, dB, dB, . . .\n");
@@ -348,16 +383,16 @@ int main(int argc, char** argv) {
 	const char* path = NULL;
 	const char* serial_number = NULL;
 	int exit_code = EXIT_SUCCESS;
-	struct timeval t_end;
+	struct timeval time_now;
 	float time_diff;
+	float sweep_rate;
 	unsigned int lna_gain=16, vga_gain=20;
-	int step_count;
 	uint32_t freq_min = 0;
 	uint32_t freq_max = 6000;
 	uint32_t requested_fft_bin_width;
 
 
-	while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:w:1Br:h?")) != EOF ) {
+	while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:w:1BIr:h?")) != EOF ) {
 		result = HACKRF_SUCCESS;
 		switch( opt ) 
 		{
@@ -427,6 +462,10 @@ int main(int argc, char** argv) {
 			binary_output = true;
 			break;
 
+		case 'I':
+			ifft_output = true;
+			break;
+
 		case 'r':
 			path = optarg;
 			break;
@@ -487,6 +526,16 @@ int main(int argc, char** argv) {
 		num_ranges++;
 	}
 
+	if(binary_output && ifft_output) {
+		fprintf(stderr, "argument error: binary output (-B) and IFFT output (-I) are mutually exclusive.\n");
+		return EXIT_FAILURE;
+	}
+
+	if(ifft_output && (1 < num_ranges)) {
+		fprintf(stderr, "argument error: only one frequency range is supported in IFFT output (-I) mode.\n");
+		return EXIT_FAILURE;
+	}
+
 	if(4 > fftSize) {
 		fprintf(stderr,
 				"argument error: FFT bin width (-w) must be no more than one quarter the sample rate\n");
@@ -581,12 +630,6 @@ int main(int argc, char** argv) {
 
 	result = hackrf_set_vga_gain(device, vga_gain);
 	result |= hackrf_set_lna_gain(device, lna_gain);
-	result |= hackrf_start_rx(device, rx_callback, NULL);
-	if (result != HACKRF_SUCCESS) {
-		fprintf(stderr, "hackrf_start_rx() failed: %s (%d)\n", hackrf_error_name(result), result);
-		usage();
-		return EXIT_FAILURE;
-	}
 
 	/*
 	 * For each range, plan a whole number of tuning steps of a certain
@@ -601,6 +644,19 @@ int main(int argc, char** argv) {
 				frequencies[2*i], frequencies[2*i+1]);
 	}
 
+	if(ifft_output) {
+		ifftwIn = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize * step_count);
+		ifftwOut = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize * step_count);
+		ifftwPlan = fftwf_plan_dft_1d(fftSize * step_count, ifftwIn, ifftwOut, FFTW_BACKWARD, FFTW_MEASURE);
+	}
+
+	result |= hackrf_start_rx(device, rx_callback, NULL);
+	if (result != HACKRF_SUCCESS) {
+		fprintf(stderr, "hackrf_start_rx() failed: %s (%d)\n", hackrf_error_name(result), result);
+		usage();
+		return EXIT_FAILURE;
+	}
+
 	result = hackrf_init_sweep(device, frequencies, num_ranges, num_samples * 2,
 			TUNE_STEP * FREQ_ONE_MHZ, OFFSET, INTERLEAVED);
 	if( result != HACKRF_SUCCESS ) {
@@ -632,32 +688,25 @@ int main(int argc, char** argv) {
 	}
 
 	gettimeofday(&t_start, NULL);
-	gettimeofday(&time_start, NULL);
 
 	fprintf(stderr, "Stop with Ctrl-C\n");
 	while((hackrf_is_streaming(device) == HACKRF_TRUE) && (do_exit == false)) {
-		uint32_t byte_count_now;
+		float time_difference;
-		struct timeval time_now;
-		float time_difference, rate;
 		sleep(1);
 		
 		gettimeofday(&time_now, NULL);
 		
-		byte_count_now = byte_count;
+		time_difference = TimevalDiff(&time_now, &t_start);
-		byte_count = 0;
+		sweep_rate = (float)sweep_count / time_difference;
-		
+		fprintf(stderr, "%" PRIu64 " total sweeps completed, %.2f sweeps/second\n",
-		time_difference = TimevalDiff(&time_now, &time_start);
+				sweep_count, sweep_rate);
-		rate = (float)byte_count_now / time_difference;
-		fprintf(stderr, "%4.1f MiB / %5.3f sec = %4.1f MiB/second\n",
-				(byte_count_now / 1e6f), time_difference, (rate / 1e6f) );
 
-		time_start = time_now;
+		if (byte_count == 0) {
-
-		if (byte_count_now == 0) {
 			exit_code = EXIT_FAILURE;
-			fprintf(stderr, "\nCouldn't transfer any bytes for one second.\n");
+			fprintf(stderr, "\nCouldn't transfer any data for one second.\n");
 			break;
 		}
+		byte_count = 0;
 	}
 
 	result = hackrf_is_streaming(device);	
@@ -668,9 +717,10 @@ int main(int argc, char** argv) {
 			   hackrf_error_name(result), result);
 	}
 
-	gettimeofday(&t_end, NULL);
+	gettimeofday(&time_now, NULL);
-	time_diff = TimevalDiff(&t_end, &t_start);
+	time_diff = TimevalDiff(&time_now, &t_start);
-	fprintf(stderr, "Total time: %5.5f s\n", time_diff);
+	fprintf(stderr, "Total sweeps: %" PRIu64 " in %.5f seconds (%.2f sweeps/second)\n",
+			sweep_count, time_diff, sweep_rate);
 
 	if(device != NULL) {
 		result = hackrf_stop_rx(device);
@@ -702,6 +752,8 @@ int main(int argc, char** argv) {
 	fftwf_free(fftwOut);
 	fftwf_free(pwr);
 	fftwf_free(window);
+	fftwf_free(ifftwIn);
+	fftwf_free(ifftwOut);
 	fprintf(stderr, "exit\n");
 	return exit_code;
 }