Trends in telematics test

Technology convergence has become a reality for manufacturers of today's automotive telematics systems. Many automobiles already include navigation, CD, AM/FM, DVD, and cellular phone capabilities—with digital video recorders, biometric ignitions, and remote diagnostics on the horizon. Once each of these new features is implemented, however, the burden on functional test greatly increases since the amount of functional test required is proportional to the number of functions. A modular, software-based test approach that takes advantage of PC architecture is required to scale functional test capability to meet these challenges. I will analyze some of the key factors driving telematics design and then present some examples of test solutions for them (see Figure 1).

It's no secret why automobiles are seeing an increase in telematics—consumers want all the amenities (and safety) of their "home" life with them on the road. But how is this convergence of technology possible, and how have designers adapted to it? One major enabler for the modern telematics system is the vast improvement in semiconductor packaging technology. Bulky dual-inline chip packages (~175 mm²) have been replaced by components as small as die-size ball-grid arrays (~1.34 mm²), greatly reducing the necessary surface area for the same processing. This trend will only continue with new packaging technology, shrinking the overall space needed for each new feature or technology set while simultaneously increasing the number of test points in manufacturing.

Chip sizes have not only reduced, they have also increased in functionality. It is not uncommon to see a single chip that integrates all of the functions required to receive AM, FM, or digital radio. In cellular technology, single chip sets such as Silicon Laboratories' Aero set can provide two- or three-band GSM transceivers using only a few additional components.

Chip size once was a limiting factor for multiband communication. Now it is less of an issue, opening the door for other functionality such as video. With the additional board space that single-chip integration provides, it's much easier to add feature after feature in telematics systems.

The amount of software in electronic devices has similarly skyrocketed. The growth of the microprocessor to more than 10,000 times the number of instructions per second compared to 20 years ago has enabled software to handle many of the tasks that used to require a completely separate hardware implementation.

One strong example of this is software radio. Designing one hardware set that will work with any number of radio communication protocols has huge potential. The military has already recognized this in the Joint Tactical Radio System (JTRS), but it will certainly extend to commercial devices in the near future. In telematics, a car buyer's feature choice might soon come down to which software gets loaded onto the console as opposed to which console gets loaded into the car.

It is important to recognize time-to-market pressures as a tremendous influence on design and testing applications as well. Powerful electronic design automation (EDA) software has reduced the number of board revisions on a design down to zero in some cases. While that increase in speed has impacted design, it has yet to be realized in other phases of the development cycle. With smaller hardware components, reconfigurable hardware, and electronic design occurring faster than ever before, a PC-based, software-centric, modular platform is one way to keep pace.

Consider the software-based functionality mentioned earlier. If a car dealer is able to add 10 different functions to a telematics system at any point in the car's operating lifetime, it's up to the manufacturing functional test to prove that they will all work, in any order of implementation, with any other functions already loaded. Essentially, the number of tests is exponentially increasing while the time and cost of test are under pressure to decrease.

Figure 2. This setup of the Mindready Automotive Multimedia and Telematics ATE system can handle simple validation applications.

Mindready's system is based on National Instruments' TestStand test-management software, which provides Mindready's customers with an open architecture to customize their systems—whether implemented as part of an extended validation or verification procedure or as an end-of-line tester. When test code is written to validate a system and set specification margins, it can be used on the same hardware incorporated for functional test. Functionality such as autoscheduling and parallel testing in TestStand is one way to address software-defined personalities—the order and combination of these features can be easily iterated with the test architecture behind the software.

The TestStand applications run on an embedded PXI controller. PXI is an industry-standard, PC-based platform capable of taking a broad range of measurements. In this case, video, audio, digital, analog, and RF are tested at a wide range of power and frequency levels. As telematics systems evolve to include these mixed-signal measurements, PXI offers a modular instrumentation platform, complete with integrated timing and triggering, capable of adapting to the latest commercial-off-the-shelf technology (Figure 3).

Each of these components makes the system adaptable to as much functionality, exposed in hardware or software, as needed in the test environment.

Another example of addressing telematics test challenges comes from Altec Visteon of Chihuahua, Mexico. The company required a flexible, nonproprietary test solution for radio and instrument cluster testing. Much like the Mindready system, Altec Visteon chose the PXI platform for measurements and switching; it chose LabWindows/CVI along with TestStand for its programming and test-management software.

Tests for the radio include audio quality, tuning, frequencies, clocks, and other display information. Many of these were accomplished with an eight-channel PXI dynamic signal acquisition module, giving Visteon the option of testing standard stereo at two channels or more complex component sound systems with additional channels. Predefined software algorithms to test output distortion, frequency response, and signal-to-noise ratios are available in the system. Tests on the instrument cluster and radio display were accomplished with a PXI image-acquisition module.

The Visteon test equipment is also expandable for future test needs. As satellite radio, Bluetooth, and holographic displays are added, the software and PXI platform can adapt with new measurement capability and additional code modules. By using the PC for system control and using modular hardware for measurements, the system met Visteon's requirement for scalability and flexibility.

The challenges overcome by the automotive industry over the last decade indicate that future systems will require even greater testing capability. As the consumer electronics market continues to redefine the standards for multimedia, everything under the sun will soon need to be under the hood. Using a flexible, scalable, and software-based measurement and automation platform is one way to address increasing functionality and time-to-market pressures.