Re: packet_loopback_hier OTA problem

500 kS/s is *really* low for the USRP B2xx. Can you try with 1MS/s? (The CPU load is very
fine)

Also, regarding your RX gain: have you verified with e.g. a time sink directly attached to
the USRP Source that the amplitudes are as you expect them to be? Something with a
magnitude value ranging up to 0.1 would be optimal, I guess.

Best regards,

Marcus

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On 07.07.21 20:51, jack houston wrote:
> htop: https://imgur.com/a/jgzo3Gk <https://imgur.com/a/jgzo3Gk>
> flowgraph: https://imgur.com/a/2XN4Z35 <https://imgur.com/a/2XN4Z35>
> I included a picture of the topology just incase I've missed anything glaring with it,
> although I did not change much at all to the example. I should note that this is the
> first time I have seen any activity on the correlation graph, as well as the HPD parser
> error, which I believe occurs when something is wrong with a packet. The CPU load looks
> fine so is this a bug I'm dealing with? I had prior issues with this example on 3.8 and
> 3.9, and even have done a complete fresh linux install since then.
>
> On Wed, Jul 7, 2021 at 12:22 PM jack houston <jack.hoston@gmail.com
> <mailto:jack.hoston@gmail.com>> wrote:
>
> When running the packet loopback example, from version 3.10, it works as expected
> without SDR involvement. However when using an SDR sink and source I have no luck
> with it working. I have tried using different configurations of sdrs, frequencies
> and gain values all known to be working on other topologies. As an example, I can
> use my Ettus B205 on a OFDM packet topology using BPSK and can correctly send and
> receive packets bar some padding issues. Using the same UHD with similiar bit rate
> and gain values on the packet_loopback_hier example yields nothing.
> The only error I that I've received is a ursp sink underflow error which should be
> irrelevant. Included is a link of a screenshot of the example file running. I was
> told by a colleague that the example has been broken for a while, but if it works
> under simulation I don't believe thats the case. From what I can tell something is
> not correctly working on the RX side of the topology, either at the PCS or the HPD.
> If someone has any knowledge about the example file and what could be causing it to
> not work in my case, I would be delighted to hear about it.
>
> File running: https://imgur.com/a/orVuSZ5 <https://imgur.com/a/orVuSZ5>
>