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Fixed calculation of elapsed UHD RX time stamp 

Now rates above 1000 RX frames per second works. The bug hit when there
were more than one frame received during one function call. This happens
if the frame rate is above the main loop rate of 1000 frames per second.
(default)
This commit is contained in:
Andreas Eversberg 2017-01-17 18:43:03 +01:00
parent ac0da3f76e
commit 23a42aeb2c
1 changed files with 33 additions and 27 deletions
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60
src/common/uhd.c
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@ -327,12 +327,12 @@ int uhd_receive(float *buff, int max)
return count;
}
if (max < (int)rx_samps_per_buff) {
PDEBUG(DUHD, DEBUG_ERROR, "SDR rx buffer too small, please fix!\n");
return 0;
}
while (max >= (int)rx_samps_per_buff) {
while (1) {
if (max < (int)rx_samps_per_buff) {
PDEBUG(DUHD, DEBUG_ERROR, "SDR rx buffer overflow!\n");
return 0;
}
/* read RX stream */
buffs_ptr[0] = buff;
count = 0;
error = uhd_rx_streamer_recv(rx_streamer, buffs_ptr, rx_samps_per_buff, &rx_metadata, 0.0, false, &count);
@ -340,30 +340,36 @@ int uhd_receive(float *buff, int max)
PDEBUG(DUHD, DEBUG_ERROR, "Failed to read from UHD device.\n");
break;
}
if (count == 0)
break;
uhd_rx_metadata_time_spec(rx_metadata, &rx_time_secs, &rx_time_fract_sec);
/* check sample rate matches time stamp increment */
if (last_secs || last_fract_sec) {
double got = ((double)rx_time_secs + rx_time_fract_sec) - ((double)last_secs + last_fract_sec);
double expect = (double)count / samplerate;
double diff = fabs(got - expect);
if (diff > 0.000000000001) {
if (check_rate) {
PDEBUG(DUHD, DEBUG_ERROR, "Received rate (%.0f) does not match defined rate (%.0f), use diffrent sample rate that UHD device can handle!\n", (double)count / got, samplerate);
return -EPERM;
if (count) {
/* get time stamp of received RX packet */
uhd_rx_metadata_time_spec(rx_metadata, &rx_time_secs, &rx_time_fract_sec);
/* commit received data to buffer */
got += count;
buff += count * 2;
max -= count;
} else {
/* got nothing this time */
if (!got)
break;
// printf("s = %d time = %.12f last = %.12f samples = %.12f\n", got, ((double)rx_time_secs + rx_time_fract_sec), ((double)last_secs + last_fract_sec), (double)got / samplerate);
/* we received previous data, so we check if the elapsed time matches the duration of the received data */
if (last_secs || last_fract_sec) {
double got_time = ((double)rx_time_secs + rx_time_fract_sec) - ((double)last_secs + last_fract_sec);
double expect_time = (double)got / samplerate;
double diff_time = fabs(got_time - expect_time);
if (diff_time > 0.000000000001) {
/* if there is an inital slip between time and data, the clock settings in the UHD device seem to be bad */
if (check_rate) {
PDEBUG(DUHD, DEBUG_ERROR, "Received rate (%.0f) does not match defined rate (%.0f), use diffrent sample rate that UHD device can handle!\n", (double)got / got_time, samplerate);
return -EPERM;
}
check_rate = 0;
rx_gap = diff_time * (double)samplerate + 0.5;
PDEBUG(DUHD, DEBUG_ERROR, "Lost rx frame(s): A gap of %.6f secods (%d samples), \n", diff_time, rx_gap);
}
rx_gap = diff * (double)samplerate + 0.5;
PDEBUG(DUHD, DEBUG_ERROR, "Lost rx frame(s): A gap of %.6f secods (%d samples), \n", diff, rx_gap);
}
check_rate = 0;
break;
}
// printf("s = %d time = %.12f samples = %.12f\n", count, ((double)rx_time_secs + rx_time_fract_sec) - ((double)last_s + last_f), (double)count / samplerate);
got += count;
buff += count * 2;
max -= count;
}
return got;