[wiki:Documentation Back] = Centralized Arbitrary Waveform Injection Subsystem (CAWIS) = This subsystem consists of arbitrary waveform generator (Agilent ESG) connected trough distribution network to four milti-band antennas located in the four corners of the grid. The distribution network enables control over the attenuation of the individual antenna feed. Using CAWIS users can inject, among other types of waveforms, AWGN signals into the main ORBIT grid and thus create different topologies. == CAWIS usage == As most of the Orbit services, CAWIS is a web-based service accessible from main grid console trough url: ''http://instrument1.orbit-lab.org:5012/interference''. Accessing this url without any other arguments will show it's help page: {{{ Interference injection control service Configures interference injection singal type to AWGN Resets interference injection subsystem to default state Set global interference injection parameters Turn on interference injection Show current status of the interference injection subsystem Turn off interference injection }}} == Example == To set AWGN on channel 36 at -30 dBm on all four antennas use the following sequence (either through a browser or '''wget''') * Step 1: Initialize the "interference" mode of the service {{{ wget http://instrument1.orbit-lab.org/initialize }}} * Step 2: Select AWGN bandwidth (channel bw for 802.11a/b/g is 20 Mhz) {{{ wget http://instrument1.orbit-lab.org/awgn?bandwidth=20 }}} * Step 3: Set power level to -30 dBm and channel number to 36 {{{ wget http://instrument1.orbit-lab.org/set?power=-30&channel=36 }}} * Step 4: Start RF injection {{{ wget http://instrument1.orbit-lab.org/start }}} At the end of the experiment, * Step 5: Stop RF injection {{{ wget http://instrument1.orbit-lab.org/stop }}}