The guts of the digital age
01 October 2007
As demand for integrated digital TV sets and digital recorders continues to rise, product manufacturers must achieve short time-to-market while delivering innovative, highly differentiated features
Digital Video Broadcasting (DVB) is transforming the way television services are consumed. Broadcasters deliver a constant stream of new offers to the market, particularly in the area of interactive services. Viewers demand the flexibility to access these services wherever and whenever they desire. User expectations of equipment performance are also increasing.
As these developments are set against the backdrop of dramatic changes to broadcast standards, the demands placed on equipment manufacturers are shifting constantly. To meet these demands, fast- track solutions are required to enable new products to be brought to market quickly and at competitive selling prices. Cost- effective, highly integrated semiconductor devices are key.
Standards and differentiation
To meet current time-to-market demands, manufacturers need turnkey solutions to many of the basic design challenges involved in building integrated digital television (IDTV) sets or digital television recorders (DTR). Functions complying with standards must be included that do not differentiate the product in the marketplace, such as MPEG2 decoder functions. COFDM demodulation meets broadcast standards set out by bodies such as the European Telecommunication Standards Institute (ETSI) or the Digital Television Group (DTG). Traditionally, engineers have used a number of off-the-shelf products, although they face the challenge of integrating components from one or more suppliers.
Greater integration of these functions will allow manufacturers to eliminate much of the engineering effort involved in building a digital TV hardware platform. This will help to shorten the development lifecycle and reduce the cost of the completed product. By also reducing the component count, a more highly integrated solution will improve reliability in the field and enable smaller, more stylish end products. The majority of digital audio/visual consumer products are required to support various functions and capabilities. Dual- stream decoding is necessary to support picture-in-picture capabilities. Dual-tuner capability is required by DTR equipment to enable simultaneous watch-and-record capability. Other requirements driven by consumers expectations include high-quality audio post-processing, including Dolby- ProLogic, Virtual-Dolby and SRS-True- Surround. High-quality video performance is also required in order to support multiple graphics and video planes, progressive scan conversion and pixel-accurate on-screen display (OSD) for panel resolutions up to 1080p for high-definition televisions (HDTV).
Integrate to innovate
A system-on-chip (SOC) approach combines the necessary graphics engine, signal demodulation circuitry, audio decoding and processing, and necessary controllers into a single device. Apart from improvements in pure video and audio performance, digital television must also have connectivity to a wide variety of devices and subsystems, including DTR hard disk drives and smart cards or conditional access modules (CAM) for subscriber authentication.
By also integrating interfaces supporting standards such as IDE, I2C and USB2.0, most integration activities can now be pre- solved at the silicon level, rather than television equipment designers confronting them in-house. For example, a DTV SOC combines a COFDM demodulator meeting the latest ETSI and DTG specifications, with numerous valuable functions for IDTV and DTR applications. The device implements audio decoding for MPEG, AC-3 and AAC formats, dual-audio decoding for scene description and multiple audio post- processing functions. The RISC core, media embedded processor functions and unified memory architecture combine to create a digital platform architecture that frees the host processor from compute-intensive DVB and multimedia processing tasks.
This highly integrated solution offers product developers the potential to focus time and resources on the user interface and styling, allowing manufacturers to deliver differentiated products at the speed demanded by modern markets.
Software integration
Manufacturers also need to implement a suitable DVB stack to meet the numerous international digital broadcast standards. Apart from the extensive software development and integration required to build and integrate the stack with the digital hardware subsystem, there is a whole host of diverse DVB standards. Furthermore, the standards are constantly changing, as more countries change to digital television. However, there is no effective harmonisation. Within the EU, for example, there is no uniform progression towards digital broadcasting across all member states. Time constraints do not allow equipment manufacturers to create unique products for each state or be familiar enough with the standards in order to do so.
The Donau LC DTV chip combines the high levels of hardware integration with a pre- integrated DVB stack capable of supporting the European DVB-T digital broadcast standard. Toshiba has worked with a specialist digital TV software supplier to port the DVB stack to the Donau LC hardware.
The stack is compliant with the required standards and is scaleable through plug-ins supporting functions such as interactive services. This allows manufacturers to introduce a range of products, including pre- verified plug-ins supporting MHEG-5 and multimedia home platform standards without having to verify compliance independently.
Internationally acceptable
A reference user interface (UI) plug-in is included, supporting functions such as multiple languages, favourites lists and country configurations. This allows manufacturers to develop a single UI for deployment in multiple territories. The plug-in provides a number of options to customise the UI, or can be used to develop more sophisticated or uniquely branded interfaces. It also allows building, testing and simulation from within a Windows development environment that can also be used to generate user manuals. With pay-TV services growing throughout the world, manufacturers need to make provision for digital TV security using recognised standards such as the DVB common interface standard. This is implemented via a plug-in to the integrated DVB software and allows manufacturers to implement multiple slots for CAMs from a wide variety of suppliers.
Equipment manufacturers need a complete solution in order to deliver price- competitive, high-performance products to valuable market segments in multiple international territories. Hardware integration, software development and porting combined with verified support for multiple digital broadcast standards enable this.
Customer satisfaction
The Donau LC hardware and DVB stack are integrated through various low-level device drivers, a glue layer and a platform abstraction layer. It is based on a Linux kernel, and uses a RISC core operating at up to 162MHz and 215MIPS. The DVB stack provides a robust low-level API designed to aid the porting process, which also allows it to be ported to a number of other processor and OS combinations. The device can be used within a DTR, requiring only the addition of a tuner and front-end memory subsystem components, output buffers and SCART matrix. On-chip interfaces also provide direct support for peripherals such as an IrDA receiver, indicator LEDs and external keyboard. High levels of integration at the silicon level, combined with pre-verified and pre-ported software components, are necessary to enable product manufacturers to deliver a constant stream of highly functional, individualised IDTV and DTR products to today’s consumers at ultra- competitive prices.
THOMAS KUSCHEL is senior manager, Microcomputer, Automotive & Consumer IC Marketing, Toshiba Electronics Europe
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