[USRP-users] Long time adquisitions with an x310

Anabel Almodovar anabel.almodovar at gmail.com
Mon Nov 11 06:22:09 EST 2019


Hello,

I am working with two ettus x310 cards whose daughter boards are TwinRx. I
am trying to acquire and save to disk 20sg at 100MHz, however this gives me
overflow. The receive buffer size is the max.
My code sends 32 bursts divided into 3 cases.

*uhd::stream_cmd_t
stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_MORE); *

* stream_cmd.num_samps = ceil(acq_num_samps/32);; *

* stream_cmd.stream_now = false;*

*stream_cmd.time_spec = usrp->get_time_last_pps(0)+1.1;*
*uhd::stream_cmd_t
stream_cmd1(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_MORE); *

* stream_cmd1.num_samps = ceil(acq_num_samps/32);*

* stream_cmd1.stream_now = true; *

* uhd::stream_cmd_t
stream_cmd2(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE); *

* stream_cmd2.num_samps = ceil(acq_num_samps/32);*

* stream_cmd2.stream_now = true; *

* usrp->issue_stream_cmd(stream_cmd); *

* for (size_t c=0; c<30 ; c++)*


* usrp->issue_stream_cmd(stream_cmd1); *

*usrp->issue_stream_cmd(stream_cmd2); *

I have also tried 25MHz acquisitions of more than 85 sg, limit imposed by
the decimated block, obtaining as error an excess in the number of samples
per burst.

*[WARNING] [X300 RADIO] Requesting invalid sampling rate from device: 200
MHz. Actual rate is: 100 MHz.*

*[INFO] [MULTI_USRP] 1) catch time transition at pps edge*

*[INFO] [MULTI_USRP] 2) set times next pps (synchronously)*

*[ERROR] [RFNOC RADIO] Requesting too many samples in a single burst!
Requested 312687500, maximum is 268435455.*

*[INFO] [RFNOC RADIO] Note that a decimation block will increase the number
of samples per burst by the decimation factor. Your application may have
requested fewer samples.*

To solve this problem, I have increased the number of bursts to have a
smaller number of samples per burst. however, I get both the broken_chain
or timeout error.

I don't know how to solve this problem and try to make longer adquisitions
without getting any kind of error (overflow, broken_chain. timeout). Could
someone offer me any help?

Thank you in advanced.

Regards,
Anabel
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