We are using a similar setup to transmit a 2x2 MIMO OFDM waveform on the
x300. Because we were not sure what to assume from a TX synchronization
point of view, we decided to put the IQ samples of both channels
interleaved in one file. We figured that reading them in sequence, IQ
sample by IQ sample, would definitely ensure that both channels are
synchronized.
But, now that I understand better how to synchronize both channels via
the UHD API, I could probably use two files, one for each channel. Any
comment?
Thanks
Ruben
*From:*Martin Braun [mailto:address@hidden
*Sent:* Monday, September 22, 2014 8:54 PM
*To:* Merz Ruben, INI-INO-ECO-MXT
*Subject:* Re: [Discuss-gnuradio] Issue with deinterleave block from a
file source to USRP sink with x300
Ruben,
I can replicate this, and am also puzzled. Will be checking if this is
an UHD issue, or a GNU Radio thing (which seems more likely given that
this only happens with the deinterleaver).
Why do you have your data in an interleaved file? This seems unnecessary.
M
On Fri, Sep 19, 2014 at 2:58 PM, <address@hidden
<mailto:address@hidden>> wrote:
Hello,
I have the following setup: a file source, a deinterleave block and
a USRP sink (see the attached .grc and related .png). This setup is
a test to distribute two different signals on two channels of the
USRP x300 (the file source loads a binary file with alternated
channels containing 64 bit long IQ samples - 32 real followed by 32
imaginary - channel 1/channel 2/channel 1/channel 2/etc...).
The hardware is a USRP x300 with two wideband SBX (SBX-120) boards.
Now, the above setup used to function without a hitch. But recently,
it completely freezes gnuradio. Basically, I start the flowgraph and
quickly get a large number of 'L' and no signal is transmitted. The
only thing I can do is then to kill gnuradio-companion and related
python processes.
The interesting thing is that if I replace the deinterleave block by
a "stream to streams" block, everything works fine. I am bit puzzled
as to what I am missing.
The operating system is Ubuntu 14.04 LTS (updated state), UHD is the
head of the maint branch, and gnuradio as well
(UHD_003.007.002-2-gdb35bf46 and Gnuradio:
9dcb5067c55a0630c9edca6b62a32b1f8e633930). Firmware is also the most
recent. I have attached the .grc, and the binary file I am using can
be obtained here:
http://www.net.t-labs.tu-berlin.de/~ruben/files/sine_test_10kHz_20kHz_cpx_float_2chan_interleaved_1MSs.bin.
Assuming there is not something wrong in my .grc setup, how do I
debug this issue?
Thanks for any suggestion or help,
Ruben
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