== Simple Radio Example with USRP X310 on ORBIT Sandbox 2 ==

=== Description ===
This tutorial shows a simple radio example - transmit a sine wave using an USRP X310 on ORBIT SB2, receive it on another X310 and view it.

=== Set Up ===
Make a reservation on the [https://www.orbit-lab.org/schedule/ Orbit Scheduler] for using SB2.
==== Prepare the nodes ====
* Load baseline-uhd-3_13.ndz on nodes 1-1 and 1-2. 
{{{
prasanthi@console.sb2:~$ omf load -i baseline-uhd-3_13.ndz -t node1-1,node1-2
}}}
* Once imaging is done, turn the nodes on and log in
{{{
prasanthi@console.sb2:~$ omf tell -a on -t node1-1,node1-2
prasanthi@console.sb2:~$ ssh root@node1-1
}}}

==== Prepare network setup for USRP access ====



=== Run the experiment ===
* Run rfnoc_spec_sense_display on the receive node. The command below starts the application to receive spectrum sensing samples from 4 USRP X310s at 100MSPS.
{{{
root@node1-19:~/uhd/host/build/examples# ./rfnoc_spec_sense_display --args="addr0=10.10.23.11,addr1=10.10.23.12,addr2=10.10.23.13,addr3=10.10.23.14,skip_ddc,skip_duc" --freq 5e9 --gain 15 --ddc-args="input_rate=200000000.0,output_rate=100000000.0" --num-usrp 4 --spec-sense-args="avg_size=256"
}}}
* Run rfnoc_spreader on the transmit node. The command below starts the application to send a 50MHz wide PN signal on node23-17.
{{{
root@node1-20:~/uhd/host/build/examples# ./rfnoc_spreader --args="addr=10.10.23.17,skip_ddc,skip_duc" --freq 5e9 --gain 15 --duc-args="input_rate=50000000.0,output_rate=200000000.0"
}}}
* Download spec_sense_display.html and open it in your browser. Once you click the Start button, you should see power spectrum display as shown below.

    || [[Image(spec_sense_display.jpg)]]||