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improved accuracy of hackrf_sweep timestamps

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This commit is contained in:
Michael Ossmann
2017-02-16 23:22:07 -07:00
parent bc49bdc344
commit fd579445df
1 changed files with 12 additions and 3 deletions
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15
host/hackrf-tools/src/hackrf_sweep.c
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@ -98,13 +98,14 @@ int gettimeofday(struct timeval *tv, void* ignored) {
#define TUNE_STEP (DEFAULT_SAMPLE_RATE_HZ / FREQ_ONE_MHZ)
#define OFFSET 7500000
#define DEFAULT_SAMPLE_COUNT 0x2000
#define BLOCKS_PER_TRANSFER 16
#define THROWAWAY_BLOCKS 2
#if defined _WIN32
#define sleep(a) Sleep( (a*1000) )
#endif
uint32_t num_samples = SAMPLES_PER_BLOCK;
int num_ranges = 0;
uint16_t frequencies[MAX_SWEEP_RANGES*2];
@ -202,11 +203,13 @@ int rx_callback(hackrf_transfer* transfer) {
int i, j;
struct tm *fft_time;
char time_str[50];
struct timeval usb_transfer_time;
if(NULL == fd) {
return -1;
}
gettimeofday(&usb_transfer_time, NULL);
byte_count += transfer->valid_length;
buf = (int8_t*) transfer->buffer;
for(j=0; j<BLOCKS_PER_TRANSFER; j++) {
@ -224,7 +227,14 @@ int rx_callback(hackrf_transfer* transfer) {
do_exit = true;
}
sweep_started = true;
gettimeofday(&time_stamp, NULL);
time_stamp = usb_transfer_time;
time_stamp.tv_usec +=
(uint64_t)(num_samples + THROWAWAY_BLOCKS * SAMPLES_PER_BLOCK)
* j * FREQ_ONE_MHZ / DEFAULT_SAMPLE_RATE_HZ;
if(999999 < time_stamp.tv_usec) {
time_stamp.tv_usec = time_stamp.tv_usec % 1000000;
time_stamp.tv_sec += time_stamp.tv_usec / 1000000;
}
}
if(do_exit) {
return 0;
@ -341,7 +351,6 @@ int main(int argc, char** argv) {
struct timeval t_end;
float time_diff;
unsigned int lna_gain=16, vga_gain=20;
uint32_t num_samples = DEFAULT_SAMPLE_COUNT;
int step_count;
uint32_t freq_min = 0;
uint32_t freq_max = 6000;