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allow selection of FFT bin width in hackrf_sweep

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This commit is contained in:
Michael Ossmann
2017-02-07 17:12:16 -07:00
parent 78b2bb98de
commit 0c45d65dc3
1 changed files with 36 additions and 11 deletions
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47
host/hackrf-tools/src/hackrf_sweep.c
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@ -99,8 +99,6 @@ int gettimeofday(struct timeval *tv, void* ignored) {
#define DEFAULT_SAMPLE_COUNT 0x4000
#define BLOCKS_PER_TRANSFER 16
#define FFT_BIN_WIDTH_HZ 312500
#define FFT_SIZE 64
#if defined _WIN32
#define sleep(a) Sleep( (a*1000) )
@ -175,7 +173,8 @@ uint32_t antenna_enable;
bool binary_output = false;
int fftSize;
int fftSize = 20;
uint32_t fft_bin_width;
fftwf_complex *fftwIn = NULL;
fftwf_complex *fftwOut = NULL;
fftwf_plan fftwPlan = NULL;
@ -250,9 +249,9 @@ int rx_callback(hackrf_transfer* transfer) {
time_str,
(uint64_t)(frequency),
(uint64_t)(frequency+DEFAULT_SAMPLE_RATE_HZ/4),
(float)FFT_BIN_WIDTH_HZ,
FFT_SIZE);
for(i=fftSize/8; (fftSize*3)/8 > i; i++) {
(float)fft_bin_width,
fftSize);
for(i=1+fftSize/8; (1+(fftSize*3)/8) > i; i++) {
printf(", %.2f", pwr[i]);
}
printf("\n");
@ -260,9 +259,9 @@ int rx_callback(hackrf_transfer* transfer) {
time_str,
(uint64_t)(frequency+(DEFAULT_SAMPLE_RATE_HZ/2)),
(uint64_t)(frequency+((DEFAULT_SAMPLE_RATE_HZ*3)/4)),
(float)FFT_BIN_WIDTH_HZ,
FFT_SIZE);
for(i=(fftSize*5)/8; (fftSize*7)/8 > i; i++) {
(float)fft_bin_width,
fftSize);
for(i=1+(fftSize*5)/8; (1+(fftSize*7)/8) > i; i++) {
printf(", %.2f", pwr[i]);
}
printf("\n");
@ -284,6 +283,7 @@ static void usage() {
fprintf(stderr, "\t[-l gain_db] # RX LNA (IF) gain, 0-40dB, 8dB steps\n");
fprintf(stderr, "\t[-g gain_db] # RX VGA (baseband) gain, 0-62dB, 2dB steps\n");
fprintf(stderr, "\t[-n num_samples] # Number of samples per frequency, 16384-4294967296\n");
fprintf(stderr, "\t[-w bin_width] # FFT bin width (frequency resolution) in Hz\n");
fprintf(stderr, "\t[-B] # binary output\n");
}
@ -320,7 +320,7 @@ int main(int argc, char** argv) {
uint32_t freq_max = 6000;
while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:Bh?")) != EOF ) {
while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:w:Bh?")) != EOF ) {
result = HACKRF_SUCCESS;
switch( opt )
{
@ -377,6 +377,11 @@ int main(int argc, char** argv) {
result = parse_u32(optarg, &num_samples);
break;
case 'w':
result = parse_u32(optarg, &fft_bin_width);
fftSize = DEFAULT_SAMPLE_RATE_HZ / fft_bin_width;
break;
case 'B':
binary_output = true;
break;
@ -437,7 +442,27 @@ int main(int argc, char** argv) {
num_ranges++;
}
fftSize = FFT_SIZE;
if(4 > fftSize) {
fprintf(stderr,
"argument error: FFT bin width (-w) must be no more than one quarter the sample rate\n");
return EXIT_FAILURE;
}
if(65536 < fftSize) {
fprintf(stderr,
"argument error: FFT bin width (-w) resulted in more than 65536 FFT bins\n");
return EXIT_FAILURE;
}
/* In interleaved mode, the FFT bin selection works best if the total
* number of FFT bins is equal to an odd multiple of four.
* (e.g. 4, 12, 20, 28, 36, . . .)
*/
while((fftSize + 4) % 8) {
fftSize++;
}
fft_bin_width = DEFAULT_SAMPLE_RATE_HZ / fftSize;
fftwIn = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
fftwOut = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
fftwPlan = fftwf_plan_dft_1d(fftSize, fftwIn, fftwOut, FFTW_FORWARD, FFTW_MEASURE);