Fueled by the growth of new technologies, consumer expectations for automotive entertainment are growing rapidly. Entertainment electronics from the home have found their way into the vehicle, merging with car-specific functions such as navigation, hands-free phone control, and telematics. The new term "infotainment" describes the complete ecosystem of electronic devices for information and entertainment inside the automobile. Audio and video devices, as well as navigation systems and telematics, are merging into single, fully-integrated systems, which naturally creates new challenges for system designers.
Much of the responsibility for the quality of the infotainment system rests with the in-car radio. Along with the reception of real-time audio and video programming, the playback of stored content also adds to the complexity of an in-dash receiver. Bulky CD drives (which require quite a bit of space) have long been considered a standard feature in cars. However, accommodations for flash memory in the form of SD-cards and memory sticks is also becoming quite common, supporting the trend in infotainment to integrate external devices. In addition, customers now expect high-end car entertainment systems to provide interfaces and support for phones, audio/video players and external memory of any kind. The industry-standard USB interface is making great market headway, while a growing number of infotainment systems also integrate Bluetooth and wireless local area network (WLAN) connections.
Apart from physical connections, the radio head unit also has to offer audio decoding capabilities, drivers, and a suitable user interface for media playback/integration. All of these functions result in complicated car infotainment systems and subsystems that require significant software and hardware effort.
Despite all of these new features, automotive entertainment still centers on the traditional AM/FM receiver. Thanks to technological breakthroughs such as new integrated circuits, filters, amplifiers, and antenna designs, sound quality has improved with each new generation of receiver. Broadcasting technology itself has also been upgraded through the Radio Data System (RDS) extension, which offers specialized features for mobile receivers.
In comparison to analog radio, terrestrial digital broadcasting systems, such as digital audio broadcasting (DAB), HD-Radio, Digital Radio Mondiale (DRM), and satellite radio, offer a suite of attractive advantages, although they are still striving to achieve mainstream customer awareness and high-volume market success. Each of these digital standards requires very specific hardware to receive and decode the audio data.
Design, quality challenges
Traditionally, including more radio functions has required additional hardware. As a result, available space within the automotive radio-head unit has effectively disappeared. The compact nature of the electronics has also caused power consumption and heat dissipation problems. For complex radios, active cooling is mandatory to stay within a safe operating temperature range. Exceeding that limit may result in performance degradation or playback dropouts, as well as increased stress on the entire system.
Because of the expected long lifetime of a car and the rather extreme automotive operating conditions, OEMs are demanding a very high level of quality and reliability for the automotive infotainment system. As a result, the components, especially the integrated circuits, have to demonstrate that they can withstand the changing temperatures, vibrations, and humidity that they will face over the lifetime of a car. For the automotive industry, it is mandatory to qualify a part according to the common AEC-Q100 standard, which was developed by major automotive car manufacturers. Parts that were originally developed for consumer applications often fail to fulfill these requirements, and are typically eliminated early in the selection process.
The close proximity of electronic systems within the radio-head unit can cause interference and electromagnetic compatibility (EMC) issues, which can result in serious performance problems. This is especially true for sensitive analog building blocks such as the receiver front end and signal lines. Designers must work carefully, using shielding and rigorous testing, to verify that the effects of EMC and interference can be controlled.
Cost is also a major design factor, and the need to minimize cost is passed throughout the entire supply chain. OEMs not only need to consider the price of the components when doing economic calculations, but also the development time for the design-in and debugging of the system. It is critical to avoid errors that come up in late project stages, so OEMs typically rely on proven vendors with a history of reliable parts that have already been used in the automotive industry.