Discussion and technical support related to USRP, UHD, RFNoC
View all threadsDear all,
I cross-compiled a small C++ application that records some IQ samples and runs stand-alone on the X410.
I want to use a sampling rate from 7.68e6 up to 15.36e6 samples per second. The IQ samples are written into the /run directory.
Unfortunately I often get overflows, so that the system is not running stable. The amount of overflows increases if I increase the sampling rate.
I also see overflows, when I run the example benchmark, e. g. like this:
/usr/lib/uhd/examples/benchmark_rate --rx_rate 15.36e6 --rx_delay 2 --priority high --rx_spb 64
I tried to play around with rx_spb from 64 to 4096, since I thought that the buffer size would make a difference. But they all showed the same behavior (sometimes overflows, sometimes not).
Within htop I cannot see any other CPU consuming services.
I was wondering if the processor is to weak to run stand-alone at these data rates. Since I also wanted to run additional decoding on low Modulation and Coding schemes on the processor this might be a problem for me.
Could you please give me some information if the x410 should be able to run the benchmark at such a sampling rate stand-alone?
For that specific case I unfortunately cannot find and results.
Many thanks again and best regards!
Jonas
Hi Jonas,
the onboard CPU (ARM64) is not for high loads, and like you suspect, is not
powerful enough to handle high loads by itself.
If you just want to capture samples at 15.36Msps, you can buffer them in
the onboard DRAM, of which you have 4 GiB in the XG_200 image, which is >
60s of streaming data if my math is correct. We have an example for how to
do that, it used to be called replay_capture.py, and was recently renamed
to rfnoc_rx_replay_samples_to_file.py (in host/examples/python).
--M
On Mon, Jul 21, 2025 at 8:37 AM von Beöczy, Jonas <
j.von-beoeczy@tu-braunschweig.de> wrote:
Dear all,
I cross-compiled a small C++ application that records some IQ samples
and runs stand-alone on the X410.
I want to use a sampling rate from 7.68e6 up to 15.36e6 samples per
second. The IQ samples are written into the /run directory.
Unfortunately I often get overflows, so that the system is not running
stable. The amount of overflows increases if I increase the sampling rate.
I also see overflows, when I run the example benchmark, e. g. like this:
/usr/lib/uhd/examples/benchmark_rate --rx_rate 15.36e6 --rx_delay 2
--priority high --rx_spb 64
I tried to play around with rx_spb from 64 to 4096, since I thought that
the buffer size would make a difference. But they all showed the same
behavior (sometimes overflows, sometimes not).
Within htop I cannot see any other CPU consuming services.
I was wondering if the processor is to weak to run stand-alone at these
data rates. Since I also wanted to run additional decoding on low
Modulation and Coding schemes on the processor this might be a problem for
me.
Could you please give me some information if the x410 should be able to
run the benchmark at such a sampling rate stand-alone?
For that specific case I unfortunately cannot find and results.
Many thanks again and best regards!
Jonas
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