Red Earth was engaged to create a test system to test antenna tuning units that are designed to work in conjunction with VHF/UHF tuneable antennas for military aircraft. The ATUs are antenna tuning devices that sit between a frequency tuneable antenna and a frequency agile radio transceiver. The radio sends tuning data in a digital serial protocol format to the UUT (unit under test), which then tunes the attached antenna.
The purpose of the system is to command the UUT with many different protocols and to monitor the UUT response. The system allows non-standard test stimuli for negative testing with the ability to generate jitter, for instance. This is controlled by a software test executive executing on a PC controlling the hardware in the TE.
The test system consists of a PC communicating with the system via Ethernet or USB. Tests are executed on the PC to test the UUT that is connected to the test system. The UUT is housed in a dark room fixture, a vision system is used to read the status of the LEDs that are mounted on the UUT with the ability to measure the frequency of the LED status.
The technical challenges were in the design of PCB (printed circuit board) that had a microcontroller communicating with FPGA (Field Programmable Gate Arrays) integrated circuits that implemented all the protocols. These items and all the cards in the rack can be remotely upgraded from the main PC via ethernet or USB.
