Re: [Discuss-gnuradio] Using two TwinRX in one x310

Hello Eugene,

I've messaged our list admin and will get your membership on the usrp-users list confirmed.

It is fully supported to use two TwinRXs in the same X310. Each DDC block in our default image has two signal paths, specifically to support the TwinRX.

The X310 fundamentally always samples a simultaneous I and Q complex pair of values. For the TwinRX we use a mux in the frontend to route the I samples and Q samples into separate signal paths. The connection type is how UHD informs itself and the FPGA how to set that mux. Other daughterboards use "IQ" or "QI" depending on how the ADC samples should logically be interpreted.

At this time it is not possible to use a UBX and TwinRX simultaneously in the same USRP. The TwinRX produces complex samples at 100 MS/s and the UBX at 200 MS/s. This mismatch requires some additional development to handle.

Regards,

Derek

On Tue, Jul 4, 2017 at 1:50 AM, Eugene Grayver <eugene.grayver@aero.org> wrote:

Hello,

 

This may be an usrp-users question, but I can't seem to get approved for that list.  Is it possible to use two TwinRX boards (4 channels) in a X310?  As far as I can tell you need 4 DDCs, but only two are available by default.

 

A followup: why is it that TwinRX connection type is reported as 'Connection Type: II' for channel 0 QQ for channel 1.

 

Finally, I have a twinrx and a UBX board in one X310.  Trying to run all 3 RX at the same time I get:

UHD Warning:

    [X300 Radio] Requesting invalid sampling rate from device: 100 MHz. Actual rate is: 200 MHz.

thread[thread-per-block[0]: <block gr uhd usrp source (1)>]: RuntimeError: Conflicting tick rates: One neighbouring block specifies 2e+08 MHz, another 1e+08 MHz.

 

 

 

Thanks

 

_______________________
Eugene Grayver, Ph.D.
Aerospace Corp., Sr. Eng. Spec.
Tel: 310.336.1274
________________________

 

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