Re: [Discuss-gnuradio] two RX paths

[Nemanja Savic]

So everything worked fine except I got the following warning:

UHD Warning:
    Mixing real and quadrature rx subdevices is not supported.
    The Q input to the real source(s) will be non-zero.

Which is probably due to my wish to use WBX with IQ and only one channel from LFTX. Is there any way to overcome this problem, and is there any explanation why this happens, cause when I use only LFTX, and particularly one channel (let say I), the Q is automatically produced within FPGA and I finally get complex baseband. Havung this in mind, why would UHD complain about real and wuadrature subdevices.

Cheers,

Nemanja

On Wed, Dec 4, 2013 at 12:20 PM, Nemanja Savic <address@hidden> wrote:

Everything is OK, I have just put "B:A A:0" in the subdevice field.

On Wed, Dec 4, 2013 at 10:47 AM, Nemanja Savic <address@hidden> wrote:

I did following: I made simple flow graph and used USRP source first with two channels and LFTX mboard. But the follwong error occurs:

  File "/home/savi_ne/work/gnuradio/GRC/top_block.py", line 105, in __init__
    self.uhd_usrp_source_0_0_1.set_center_freq(433900000, 1)
  File "/usr/local/lib64/python2.6/site-packages/gnuradio/uhd/uhd_swig.py", line 1872, in set_center_freq
    return _uhd_swig.uhd_usrp_source_sptr_set_center_freq(self, *args)
RuntimeError: vector::_M_range_check

When I tried with setting two mboards, with LFTX A channel subdevice in the first channel (B:A option_ and WBX on the second channel I get following error:

  File "./top_block.py", line 101, in __init__
    self.uhd_usrp_source_0_0_1.set_subdev_spec("A:0", 1)
  File "/usr/local/lib64/python2.6/site-packages/gnuradio/uhd/uhd_swig.py", line 1831, in set_subdev_spec
    return _uhd_swig.uhd_usrp_source_sptr_set_subdev_spec(self, *args, **kwargs)
RuntimeError: vector::_M_range_check

And as far as I have seen GRC doesn't put anything in the field device_addr for changing FPGA image.

On Tue, Dec 3, 2013 at 6:03 PM, Marcus D. Leech <address@hidden> wrote:

On 12/03/2013 12:00 PM, Nemanja Savic wrote:

Thank you Marcus again,

I changed device address, in both places, but the same problem appears. I see that it loads now 4rx image, but the problem remains.

        self.uhd_usrp_source_1 = uhd.usrp_source(
            device_addr="fpga=usrp1_fpga_4rx.rbf",
            stream_args=uhd.stream_args(
                cpu_format="fc32",
                channels=range(1),
            ),
        )

You should probably start with a GRC flow-graph with a single UHD USRP source, with two channels being what you want, and look at the generated
  Python code.

--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

--
Nemanja Savić

--
Nemanja Savić

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Nemanja Savić