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View all threadsProblem when working with USRP 200b mini in TX mode
I recently started working with the USRP 200b mini in TX mode. I set up the input data(). When setting the tx_rate below 56, everything works fine, there is no data loss, the traffic is good (it is taken from the file), but as soon as I set the tx_rate to 56, I have an underflow(U). I started to study why this happens. The USRP is connected to a USB 3.1 port, with a connecting cable (also with a good transfer rate). In the documentation, tx_rate is supported at 56, if you set more, it resets to 56. I don't quite understand what I'm doing wrong, maybe I forgot to specify something or need to enable (disable) it somewhere, I hope for your advice. UHD 4.8.0.0, Boost ++ 1.87.0 drivers , OC Windows 10.
On 05/03/2025 08:17, able5541@oxobrowser.com wrote:
I recently started working with the USRP 200b mini in TX mode. I set
up the input data(). When setting the tx_rate below 56, everything
works fine, there is no data loss, the traffic is good (it is taken
from the file), but as soon as I set the tx_rate to 56, I have an
underflow(U). I started to study why this happens. The USRP is
connected to a USB 3.1 port, with a connecting cable (also with a good
transfer rate). In the documentation, tx_rate is supported at 56, if
you set more, it resets to 56. I don't quite understand what I'm doing
wrong, maybe I forgot to specify something or need to enable (disable)
it somewhere, I hope for your advice. UHD 4.8.0.0, Boost ++ 1.87.0
drivers , OC Windows 10.
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Presumably, you mean 56 megasamples/sec?
The 'U' indications that your computer isn't keeping up with the radios
demand for samples. The radio supports a maximum
sample-rate of 56 megasamples/sec.
Where are you pulling the samples from? A local file? Are you
constructing the samples in real-time?
You might get better results with setting a device argument of
"num_send_frames=256", which can sometimes help.
If you use "benchmark_rate", it will tell you if your computer, when
doing absolutely NOTHING with the samples, can
keep up with the specified sample rate.
Your computer has to work harder and harder the higher the sample rate.
The amount of "work" your computer has
to do is proportional to the product of the "inherent per-sample
computational complexity" X sample-rate.
Hello,
Presumably, you mean 56 megasamples/sec? - Yes, by setting it to usrp->set_tx_rate(56e6); When setting the clock frequency, usrp->set_master_clock_rate(56e6);
The 'U' indications that your computer isn't keeping up with the radios demand for samples. The radio supports a maximum sample-rate of 56 megasamples/sec. -
I've read about this, but I don't actually have a good, powerful computer, because the computer doesn't freeze or glitch when working. The only thing I assumed was that it was a USB port, it might not work correctly, but I inserted the USRP into the 3.1 and 3.0 ports, there was no difference, right into the motherboard (back).
Where are you pulling the samples from? A local file? Are you constructing the samples in real-time? - I get the samples from a local file.
If you use "benchmark_rate", it will tell you if your computer, when doing absolutely NOTHING with the samples, can keep up with the specified sample rate.
Your computer has to work harder and harder the higher the sample rate. The amount of "work" your computer has to do is proportional to the product of the "inherent per-sample
computational complexity" X sample-rate. - I'll try to do a benchmark_rate, and I'll post the results.
Sorry, I didn't quite understand how to insert your quotes in the response, so I copied them and answered with a "-".