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View all threadsSet the gain settings in C++ API for B210
Hello, I'm having some trouble with the UHD API. I'm trying to build a
simple receiver code by following the examples in the 'rx_samples_to_file'
and 'rx_timed_samples'. When I'm using the rx_samples_to_file example and
try to set the gain settings through the command line, (/rx_samples_to_file
--freq 98e6 --rate 5e6 --gain 20 --channels 0,1 --duration 10
usrp_samples.dat).
I get an error saying " RX channel 18446744073709551615 out of range for
configured RX frontends".
Basically I want to be able to use both received channels simultaneously
and set the gain for both, like you can in GNU Radio Companion. If I don't
set the gain then it runs as expected. I've tried adding more parameters
such as 'ant' and 'subdev' but it doesn't seem to work.
Thank you
On 07/09/2023 00:18, swapnil srivastava wrote:
Hello, I'm having some trouble with the UHD API. I'm trying to build a
simple receiver code by following the examples in the
'rx_samples_to_file' and 'rx_timed_samples'. When I'm using the
rx_samples_to_file example and try to set the gain settings through
the command line, (/rx_samples_to_file --freq 98e6 --rate 5e6 --gain
20 --channels 0,1 --duration 10 usrp_samples.dat).
I get an error saying " RX channel 18446744073709551615 out of range
for configured RX frontends".
Basically I want to be able to use both received channels
simultaneously and set the gain for both, like you can in GNU Radio
Companion. If I don't set the gain then it runs as expected. I've
tried adding more parameters such as 'ant' and 'subdev' but it doesn't
seem to work.
Thank you
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When I've seen this behavior in the past it has been because the UHD
example apps were linked against one version of the UHD
library, and then another version of that library was installed onto
the system underneath them--you have a library version
mis-match.
Possibly when you installed Gnu Radio from the packaged repositories
AFTER doing a manual build of UHD, or some other
incompatible UHD install.
Well would you say that's still the case if I can run the example if I just exclude certain parameters? For example if I just give a sample rate, freq, duration it runs fine. It's just that when I pass the gain parameter the error shows up. Furthermore, other examples such as rx_samples_to_udp also run fine, even when I add a gain parameter. The issue comes when I try to modify the udp example to include 2 channels, then it fails with the same error stated above.
On 07/09/2023 20:01, 1920swapnil@gmail.com wrote:
Well would you say that's still the case if I can run the example if I
just exclude certain parameters? For example if I just give a sample
rate, freq, duration it runs fine. It's just that when I pass the gain
parameter the error shows up. Furthermore, other examples such as
rx_samples_to_udp also run fine, even when I add a gain parameter. The
issue comes when I try to modify the udp example to include 2
channels, then it fails with the same error stated above.
Well, if the standard examples work, and yours doesn't, I would say that
you need to review your modifications to make sure they're
"sane".
It's unlikely that UHD has a bug that causes the "set_gain()" method to
not work in some cases, and two streams vs a single
stream isn't a particularly "weird" case.
When stuff like this happens--where you modify an example, the onus is
on you to do basic debugging, as you would
with any compiled language like C++ or C. Put in some debugging
print statements before and after the call, for example.
Make sure you're providing adequate-sized buffers, so that sample
data isn't over-writing other things in your modified
code. Remember, C++ has NO run-time bounds checking. Everything is
done at compile time, and if a bound cannot
be checked at compile time, there isn't a runtime there to tell you
exactly what you did wrong. That's true of pretty-much
ALL C/C++ programs.
Maybe I didn’t clarify properly, the standard example ‘rx_samples_to_file’ example works correctly if I don’t provide any gain argument, but fails when I do. I understand my own examples would require me to debug, but I would like to understand why the standard examples don’t work for my specific set of arguments, whether that’s because my arguments are incomplete/incorrect or if that’s because that’s the expected result for a b210.
On 07/09/2023 21:26, 1920swapnil@gmail.com wrote:
Maybe I didn’t clarify properly, the standard example
‘rx_samples_to_file’ example works correctly if I don’t provide any
gain argument, but fails when I do. I understand my own examples would
require me to debug, but I would like to understand why the standard
examples don’t work for my specific set of arguments, whether that’s
because my arguments are incomplete/incorrect or if that’s because
that’s the expected result for a b210.
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Then we're back to mis-matched libraries almost certainly.
What version of UHD libraries do you have installed--how did you
install them? Did you then install Gnu Radio, which may
have pulled in a different version of UHD.
I just tried that example on my Ubuntu 22.04 system, with UHD 4.1.0.5,
and it worked just fine.
I have the version 4.4.0.0 on ubuntu 22.04. I followed the ‘ Building and Installing the USRP Open-Source Toolchain (UHD and GNU Radio) on Linux’ guide, and yes I did install GNU Radio afterwards. I’ll try to uninstall GNU Radio to see if that fixes the issue.
On 07/09/2023 21:56, 1920swapnil@gmail.com wrote:
I have the version 4.4.0.0 on ubuntu 22.04. I followed the ‘ Building
and Installing the USRP Open-Source Toolchain (UHD and GNU Radio) on
Linux’ guide, and yes I did install GNU Radio afterwards. I’ll try to
uninstall GNU Radio to see if that fixes the issue.
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Given that the B210 hasn't had any updates in quite some time, there's
no reason to have the "very latest" UHD, and the
version that is packaged with Ubuntu should be just fine.
It's likely that you have a conflict between the "installed from the
distro repo" versions of UHD and Gnu Radio, and the
bits and pieces that you compiled and installed from source. The
"mixed system" syndrome.