N210 xcvr2450

dubstep · July 29, 2011, 6:41pm

Hi,

I am trying to send data from a N210+XCVR2450 to another N210+XCVR2450.
Both equipment have antennas connected at J2 antenna input and they are
connected to the same computer using 2 gigabit ethernet ports. I have
assigned different ip addresses and executing “uhd_find_devices” gives
the
following result

– UHD Device 0

Device Address:
type: usrp2
addr: 192.168.20.2
name:
serial: E2R12XEUP

– UHD Device 1

Device Address:
type: usrp2
addr: 192.168.10.2
name:
serial: E3R12X7UP

Executing uhd_usrp_probe --args=addr=192.168.10.2 gives

linux; GNU C++ version 4.5.2; Boost_104200; UHD_003.002.000-0e6441c

– Opening a USRP2/N-Series device…
– Current recv frame size: 1472 bytes
– Current send frame size: 1472 bytes

Executing uhd_usrp_probe --args=addr=192.168.20.2 gives

linux; GNU C++ version 4.5.2; Boost_104200; UHD_003.002.000-0e6441c

– Opening a USRP2/N-Series device…
– Current recv frame size: 1472 bytes
– Current send frame size: 1472 bytes

Both devices have UHD-images-003.002.000 fw and fpga built. I have tried
usrp_n210_r4_fpga.bin and usrp_n210_r2_fpga.bin FPGA images. They both
give
similar performances. Couple of days ago I have compiled UHD and
gnuradio
after I get the latest version from git repository.

Since I don,t have a spectrum analyzer, I can not check the output of
TX.
Both devices are tuned to the same frequency I am expecting to get some
signal at the RX. Till now I have received only noise.

There is a 2.4GHz WLAN in the building and I tried to capture WLAN
signals
using uhd_fft.py but this also failed.

I have attached gnuradio-companion file that I used and screen captures.

Is there anything I am missing? Any suggestions?

Regards,

Burak Kelleci

Burak_Kelleci · July 29, 2011, 6:59pm

On Fri, 2011-07-29 at 19:40 +0300, Burak Kelleci wrote:

Device Address:
type: usrp2
addr: 192.168.10.2
name:
serial: E3R12X7UP

Executing uhd_usrp_probe --args=addr=192.168.10.2 gives

Both devices have UHD-images-003.002.000 fw and fpga built. I have tried
usrp_n210_r4_fpga.bin and usrp_n210_r2_fpga.bin FPGA images. They both give
similar performances. Couple of days ago I have compiled UHD and gnuradio
after I get the latest version from git repository.

First, don’t upload r4 images to your N210. Use the version that
corresponds to the sticker on the back of your N210, which is R2 since
we haven’t actually shipped any rev 4 units yet. Using rev 4 FPGA images
on your rev 2 N210 will result in transmitting and receiving nothing but
zero samples.

Other than that, your flowgraph looks OK and you should see something on
your receiver spectrum.

–n

Burak_Kelleci · July 29, 2011, 7:09pm

On 29/07/2011 12:40 PM, Burak Kelleci wrote:

Hi,

I am trying to send data from a N210+XCVR2450 to another N210+XCVR2450.
Both equipment have antennas connected at J2 antenna input and they are
connected to the same computer using 2 gigabit ethernet ports. I have
assigned different ip addresses and executing “uhd_find_devices” gives the
following result

Try this experiment.

Wire your antenna for J1 (the default) on one of the N210 units (after
installing the correct firmware, as noted by Nick).

Use uhd_fft.py --f 5.5G -g 40 -s 5.0e6

And see if you can ‘see’ the unit that is transmitting at 5.5G. You
should see two spikes–at +100Khz and -100Khz.

Also check other frequencies that you should be able to see, like your
local WiFi 2.4GHz signals.

Burak_Kelleci · August 3, 2011, 9:21pm

On Wed, 2011-08-03 at 22:09 +0300, Burak Kelleci wrote:

Hi,

I have replaced XCVR2450 with LFTX and checked the output using an oscilloscope.
I have applied an AM signal with 100KHz carrier frequency and 10KHz message signal
frequency. I selected the amplitudes so that total signal amplitude is always less
than 1. Sampling frequency is selected as 1MHz. For 003.002.000 release the output
is not as expected. However, for 003.002.001 release the output matches to the
expected waveform. However, XCVR2450 did not work with 003.002.001 release. I
attached the error. I also tried to recompile and reinstall UHD and gnuradio.
Unfortunately the result is the same.
Any suggestions?

OK, I know the problem now. There was a timing bug in the 3.2.0 FPGA
image release that affected some N210 users. The issue has been resolved
in 3.2.1.

Like Josh says, the error you are seeing indicates that there are
multiple copies of the UHD host library on your machine, or you haven’t
built the corresponding 3.2.1 host code yet.

–n

Burak_Kelleci · August 3, 2011, 9:10pm

Hi,

I have replaced XCVR2450 with LFTX and checked the output using an
oscilloscope. I have applied an AM signal with 100KHz carrier frequency
and 10KHz message signal frequency. I selected the amplitudes so that
total signal amplitude is always less than 1. Sampling frequency is
selected as 1MHz. For 003.002.000 release the output is not as expected.
However, for 003.002.001 release the output matches to the expected
waveform. However, XCVR2450 did not work with 003.002.001 release. I
attached the error. I also tried to recompile and reinstall UHD and
gnuradio. Unfortunately the result is the same.
Any suggestions?

Burak Kelleci

Burak_Kelleci · August 4, 2011, 2:22pm

On 08/03/2011 12:09 PM, Burak Kelleci wrote:

recompile and reinstall UHD and gnuradio. Unfortunately the result is
the same. Any suggestions?

I am being punished for not incrementing the compat number. So I have to
answer another one of these emails. You are using pre-release code from
the master a few weeks ago and who knows what FPGA and firmware images.

Please install UHD from either the latest master branch, or a release
tag, or from a pre-built release package. The FPGA and firmware images
must match with the host code:
http://code.ettus.com/redmine/ettus/projects/uhd/wiki#Binary-downloads

-josh