SV: [Discuss-gnuradio] Samples alignment of two USRP2s with seperate ethernet ports

[Patrik Eliardsson]

Hi,

 

Yes we have solved it but it is not perfect yet, probably due to jitter in clocks, the threshold level at the 1PPS input and the quality of the 1PPS and 10MHz signals. The topic have also been touched here:

http://lists.gnu.org/archive/html/discuss-gnuradio/2009-08/msg00173.html

 

-Patrik

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Från: address@hidden [mailto:address@hidden För hanwen
Skickat: den 8 september 2009 15:19
Till: address@hidden; Ulrika Uppman
Ämne: [Discuss-gnuradio] Samples alignment of two USRP2s with seperate ethernet ports

Hi GRers,

 

I'm quite new to USRP2. We are building a wideband MIMO receiver with two USRP2s. In order to archieve high bandwidth (20MHz) we have to use two independent ethernet ports to host computer.

The question is how to get the the raw samples from different ethernet ports aligned. We plan to use a common 10MHz ref clock and 1 PPS source synchronizing the two USRP2s. However, as the softwares for the two boards are not starting exactly in the same time, there should be a fixed delay between the two channels of samples. How to get over this?

I read from this thread

http://lists.gnu.org/archive/html/discuss-gnuradio/2009-06/msg00075.html

regarding maybe the same issue. Has it already been solved?

 

Thank you in advance.

 

Hanwen