[USRP-users] TX and RX phase compensation on B210

Eleftherios(Lef) Kampianakis e.kampianakis.ee at ieee.org
Wed Oct 22 16:50:22 EDT 2014


Hello everyone,

I have a project that requires knowledge of the phase difference that is
introduced between TX and RX.


I started with a simple GRC block diagram (im1) with two file sinks
attached to a UHD_source and UHD sink respectively. I connected tx/rx1 and
rx1 with coax cable and  I used  MATLAB  to send and get samples. However,
every received vector of samples had different phase compared to the rx
vector.

Subsequently, I developed a simple GRC block diagram (im2) that just sends
and receives a constant carrier and plotted the time domain transmitted and
received signals using scope. The signals exhibit a constant phase
difference but when I restart the scrip this phase difference changes.

Finally I developed a python script that has a vector sink and source,
generated a carrier in python and plotted the samples I send vs the samples
I received. The phase, again wasnt the same in every execution.

Do you have any suggestions on how can I implement a script that either
phase is constant everytime I execute it or I can have knowledge of it
everytime? I have already started looking at UHD code examples but I dont
want to dig that deep without eliminating all other easier tools.


Thank you
-- 
Eleftherios(Lef) Kampianakis
Electronics and Computer Engineer
PHD Candidate and Researcher at Sensing Computing Communications Group
(SGCC)
Department of Electrical Engineering
University of Washington
3927 Adams Lane, NE, Mercer Court D805B, 98105
website: http://staff.washington.edu/ekampian
mail:e.kampianakis.ee at ieee.org
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