Re: [Discuss-gnuradio] Signal distorted when using concurrently two USRP B210 devices

[George Vardakis]

Good evening,

I attach three captures to show you the problem, one with the reference signal i transmit, one with the received samples when using the same device for TX and RX and one with the received samples of the one device, when the second one transmits. I also attach the flowgraph i used for this capture. The sampling rate i use is 1MHz. The specific captures are done with the USRPs over USB-2 ports, but i have also tried over USB-3 and observed the same behavior.

Thank you for your time​

 same_tx_rx_device.dat

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 refference.dat

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 different_tx_rx_device.dat

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On Tue, Jun 13, 2017 at 12:04 AM, Marcus D. Leech <address@hidden> wrote:

On 06/12/2017 03:53 PM, George Vardakis wrote:

Hello all,

I have two USRP B210 devices which i use in my MIMO application. When i use the two of them concurrently in a flowgraph - or different flowgraphs - i notice that the signal received by the streams of one of the devices (the one whose serial number is last in lexicographical order) is distorted. Because i transmit a known training sequence, i know what to expect, and i observe that sometimes the real or imaginary part of the signal has flipped its sign (i see the signal mirrored compared to the known one), or other times it is completely distorted. When i use each device separately, everything works fine. The UHD driver i use is the v3.9.5 one.Any ideas about it?

Thank you!  

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COuld you perhaps share a very-simple flow-graph that shows the issue?

What sample-rate are you using?  Is this over USB-2 or USB-3?

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test.grc
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