Re: [Discuss-gnuradio] S printouts and then either U printouts (and fails/stops transmitting) or seg fault with 4 USRPs

[Martin Braun]

On 06/22/2016 11:19 PM, Marcus Müller wrote:
> Hi Pavan,
> 
> sorry for not answering earlier.
> 
> So, my main concern here is the fact you're instantly seeing "S"s; these
> are /S/equence errors, and they usually only happen if the network
> hardware, or software firewall or something similar, reorder packets
> coming from the same USRP.
> 
> So, how are your four USRPs connected to your host?

And which USRPs are these?

M
> 
> 
> Best regards,
> 
> Marcus
> 
> 
> On 23.06.2016 04:36, Pavan Yedavalli wrote:
>> Hi,
>>
>> I am connecting 4 USRPs to the Octoclock and my host CPU, and created
>> two of my own blocks (one in python and one in C++), but neither of
>> them runs very long, as countless Ss are streamed out and then finally
>> Us, which signify underruns and so they stop transmitting. I was told
>> that implementing the block in Python would be slower, as expected,
>> which could be the reason why my computer is not able to transmit
>> samples to the USRPs quickly enough. However, when I tried to
>> implement in C++, which is supposed to be much faster, I'm seeing the
>> same problem.
>>
>> One key piece of information is that both the python and C++
>> implementations work about 75% of the time when 2 USRPs are connected,
>> but with 4, it fails quickly close to 100% of the time, so it is clear
>> that adding more antennas is causing issues, but I don't know what I
>> can do about it. My project requires multiple antennas, so this is a
>> major problem, unfortunately. Any help would be much appreciated.
>> Thank you so much.
>>
>> -- 
>> Pavan
>>
>>
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> 
> 
> 
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