Re: GNURadio/USRP stream tag execution not as expected

[Jeff Long]

Just as a guess ... on the X310, all the tags arrived in the same work() call, so they were all applied at the same time, spaced by the amount of time it took to toggle the gain up and down over the ethernet interface. On the B210, there must have been one tag per buffer. It's also possible that the control interface on the X310 is out-of-band and the B210 is in-band.

On Wed, Mar 29, 2023 at 2:12 PM Nicolas Buhr <buhr.nicolas@gmx.de> wrote:

That‘s ok. I can add arbitrarily long guard intervals, where I need to change the gain. I actually can not leave the radio gain at the highest needed, because I need about 30dB gain difference and at -30dB the ADC resolution isn‘t sufficient anymore.

But if you could have a look at the pictures I posted on stackoverflow (Link below in my original post), it’s odd, that there is so much difference between the result with B210 and X310.

Am 29.03.2023 um 16:04 schrieb Jeff Long <willcode4@gmail.com>:



You will not get a radio to adjust its gain anywhere near that quickly. You could leave the radio gain at the highest you will need, and vary the amplitude of your signal.

On Tue, Mar 28, 2023 at 5:46 PM Nicolas Buhr <buhr.nicolas@gmx.de> wrote:

Hi everyone,

I already posted this to stackoverflow, but maybe somebody here can help me as well.

I’m working with a USRP B210/X310 and I’m trying to send a frame with containing some payload, with synchronization sequences before and after the payload. For interesting measurements bit error rate measurements, I want to get a low SNR for the payload. Since I need a much better SNR for more synchronization, I’m trying to send the synchronization sequence with a high gain, while sending the payload with a much lower gain.

Trying to implement this I encountered some unexpected behavior while using the tagged stream commands for the GNURadio block. So I went back and made the most simple setup, I could imagine.

The results and the actual problem can be seen in the screenshots in my stackoverflow post:

https://stackoverflow.com/questions/75869595/gnuradio-usrp-stream-tag-execution-not-as-expected

Any ideas, where to look for/how to remove the error?

Thanks in advance,

Nicolas Buhr