== Working with GNU and Nutaq ==

=== Description ===
This example will demonstrate how to use GRC (GNU Radio Companion) with Nutaq's Zepto SDR.

=== Set up ===
To get started, make a reservation on the grid and then load the ''ubuntu-14-04-64bit-sdr.ndz'' on two nodes - one node with a Zepto SDR and the other node a USRP. For this example we'll use node20-13 and node20-20 which have a Zepto SDR and USRP, respectively.
{{{
user@console.grid:~$ omf load -i ubuntu-14-04-64bit-sdr.ndz -t [[20,13],[20,20]]
}}}

Turn on both nodes and verify that the interface to each SDR is configured correctly. Verify connection to Zepto SDR:
{{{
ifconfig eth2 192.168.0.1 netmask 255.255.255.0 mtu 9000 up
ping 192.168.0.101
}}}

Verify connection to USRP:
{{{
ifconfig eth2 192.168.10.1 netmask 255.255.255.0 mtu 9000 up
ping 192.168.10.2
}}}

=== Run the GRC scripts ===

Download the receiver ''zepto_rx.grc'' into node20-13 and open it with GNU Radio Companion.
{{{
root@node20-13:~# cd /opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples# wget http://www.orbit-lab.org/raw-attachment/wiki/Tutorials/k0SDR/Tutorial10/zepto_rx.grc
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples# cd ..
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq#sh launch_gnuradio_companion.sh &
}}}

A window should pop up similar to the following:
  || [[Image(zepto_rx.png, width=500px)]] ||


Next download the transmitting side ''usrp_tx.grc'' and open with GNU Radio Companion.
{{{
root@node20-20:~# wget http://www.orbit-lab.org/raw-attachment/wiki/Tutorials/k0SDR/Tutorial10/usrp_tx.grc
root@node20-20:~# gnuradio-companion
}}}

A window should pop up similar to the following:
  || [[Image(usrp_tx.png, width=500px)]] ||


On both GRC windows click on the execute (side ways triangular) button to start both scripts. On the receiver side and spectrum window should open showing a carrier frequency. The details of the center frequency, power, gain, etc are in the GRC files - tweak a some of the parameters and validate by observing the spectrum.