Recording data from 2 USRP daughterboards simultaneously

Hi,

I am trying to record I/Q data from two daughterboards (currently a
TVRX and a RFX400) on one USRP simultaneously. I have no trouble
recording data from either of these daughterboards independently, but
when I try to record data simultaneously, I receive the following error:



#./usrp_rx_cfile.py -R A -d 10 -g 65 -f 491e6 data
usrp_open_interface:usb_claim_interface: failed interface 2
could not claim interface 2: Device or resource busy
usrp_basic_rx: can’t open rx interface
Traceback (most recent call last):
File “./usrp_rx_cfile.py”, line 105, in ?
my_graph().run()
File “./usrp_rx_cfile.py”, line 61, in init
self.u = usrp.source_c(decim_rate=options.decim)
File “/usr/local/lib/python2.4/site-packages/gnuradio/usrp.py”,
line 248, in init
fpga_filename, firmware_filename)
File “/usr/local/lib/python2.4/site-packages/gnuradio/usrp1.py”,
line 1232, in source_c
return _usrp1.source_c(*args)
RuntimeError: can’t open usrp1



This seems to be an inability to open the USB port on the second call
to usrp_rx_cfile.py. Is there a simple workaround to this problem?

Regards,
Brent


Brent M. Ledvina
Assistant Professor
Bradley Department of Electrical and Computer Engineering
Virginia Tech
Blacksburg, VA 24061
ph: 540.231.0656
Office Hours: T 1-3, W 11-12

On Tue, Aug 21, 2007 at 03:49:30PM -0400, Brent M. Ledvina wrote:

#./usrp_rx_cfile.py -R A -d 10 -g 65 -f 491e6 data
fpga_filename, firmware_filename)
to usrp_rx_cfile.py. Is there a simple workaround to this problem?

Regards,
Brent

Hi Brent,

You’ll need to write a small bit of code. The Rx side of a USRP can
only be opened once. Thus, you need a single program that reads input
from both daughterboardsd at the same time.

Take a look at gnuradio-examples/python/multi-antenna/multi_file.py.
It handles 4 simultaneous inputs. Your case will be similar, only
using 2. Also, when using 2 inputs, there’s no need to load special
fpga firmware. The standard file works fine. The channel filter
won’t be required either. We needed it for our application.

Eric

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs