System Design and Configuration
The test system we constructed has four major components – the PXI controller, a vector measurement system, the existing Anritsu network analyser and the software. The controller communicates with the Anritsu network analyser through its GPIB interface. This helps the operator measure scalar quantities, such as standing wave ratio and transmission loss, in addition to vector quantities, such as phase difference. We used NI LabVIEW, along with several NI toolkits, to develop the application.

With NI tools, we developed the new phase-matching, data-capture software. We then customised this software for this particular application. Additionally, we created advanced custom analysis functions to manipulate the incoming data set for comparison against test procedure requirements. We then used the data to produce the test report.

The system consists of two main sections – the PXI chassis, which contains the vector analyser and the GPIB interface to the scalar system.

We assembled the PXI technologies in the NI PXI-1045 chassis to create a vector analyser, which helps operators accurately measure the phase difference between two RF cables in the Gigahertz range. The operators connect the cables under test across the two switch cards to minimise any difference in switching path lengths between the two units. The test frequencies are in the Gigahertz range and any delay introduced by either of the switch cards can result in inaccurate measurements.

All of the system hardware is stored in an existing 3U rack–mountable, rugged container for increased protection.

cable connections without displaying redundant details. We achieved this by using picture rings to illustrate the setup, calibration and testing steps. These pictures show operators exactly what to connect and where.

We needed to tailor the system to BAE Systems’ specific layout design requirements and build it under tight security. Sections of the test procedure are considered sensitive, so we designed and implemented the software without knowing the full test criteria. For sensitive parts of the test, the operator

must enter those parameters before beginning each test. This means all information is kept in volatile memory and is lost if the system is shut down, thus meeting BAE Systems’ security requirements.

The test system also must determine when a system calibration is required. We attempted several test-sequence iterations to ensure we kept calibrations to a minimum because they have an adverse effect on test duration. With the resulting sequence, operators can batch test cables at the same frequencies, as long as there are no physical restrictions due to the design of the aircraft.

We controlled the vector analyser through the GPIB interface to conduct all calibration and test routines without operator interference. This was particularly difficult because the analyser was in constant use and could not be released for off-site work. We developed the control VIs off site and commissioned them on site when production program time allowed.

Producing Easy-to-Use Results
The combined system produces results for all tests conducted on each product and the operator can produce a printout anytime.

The system displays the results in graphical and tabular formats and produces a detailed cover sheet that shows the time, date, operator and product identifier for the test subject. The graphical format illustrates all values for the required 401 test points, with limit lines to show

the pass/fail criteria. The tabular format shows the maximum values achieved and includes a pass/fail box for clarity.

Using the LabVIEW Report Generation Toolkit for Microsoft Office, operators can record the results in Excel documents. With these results, aircraft inspectors can see quickly and easily the overall result and keep the graphical detail sheets for future reference.