DIGITAL TV - cable set-top box
Overview
Cable companies are under continuous pressure to reduce new customer acquisition costs and to increase revenue-per-subscriber. Now, with today’s technology, cable companies have a tremendous opportunity to enhance their subscribers’ entertainment experience, reduce turnover, attract new subscribers , add services to existing subscribers, and ultimately increase revenue.
Digital TV technology leapfrogs old analog technology and delivers stunning DVD-like picture quality. Digital technology also enables cable operators to deploy a host of revenue generating services such as VOD (Video-On-Demand), PVR (Personal Video Recording), and e-commerce.
With the addition of a broadband connection, the opportunities become endless. Basic boxes may start with services such as email and home shopping while advanced boxes will enable interactive TV, gaming, streaming audio and video, voice over IP (VoIP), and video telephony. Furthermore, all these applications will be delivered with high-quality 2D and 3D graphics that, not long ago, were reserved for the high-end gaming market.
One of the challenges faced by cable operators is to deliver these new services in a cost-effective manner. Unlike analog television, every digital television requires its own set-top box to decode and display the digital signals. Two TVs means two set-top boxes, which are often provided free of charge or with a minimal rental fee by the cable operator. This quickly turns into an expensive proposition for the cable operator, thus slowing the rollout of digital TV and services to consumers.
Throughout the cable industry, innovative operators and set-top box manufacturers are exploiting new technology that allows one set-top box to control two TVs in one home, thus reducing deployment costs.
Methodology
The coaxial cable feed enters the home and goes directly into the set-top box. Two or more tuners allow the box to select between the multiple video channels being broadcast over the cable network. One output of the set-top box is connected to the TV in the family room. Meanwhile, a second output is connected to a second TV in the bedroom. This second connection may be made via existing coaxial cable or perhaps even through a wireless network. The second TV can be used to simultaneously watch a second program, surf the Internet, or play an interactive 3D video game, with virtually no additional cost to the cable operator.
Example product requirement
Design a single set-top box capable of receiving multiple digital and analog channels and displaying them on two different TVs.
Solution
The Xilleon 220 from ATI is the perfect System-On-Chip to form the heart of this platform. The Xilleon 220 architecture combines all major digital video, audio, and I/O functions onto a single chip, including conditional access, video stream parsing and MPEG video decode, graphics, TV output, and I/O. The powerful MPEG video processor on the Xilleon 220H can decode up to two high-definition video streams, or multiple standard-definition streams while the Xilleon 220S is limited to decoding standard-definition streams. The Xilleon 220H and Xilleon 220S can also drive two TVs with independent video and graphics on each TV.
Dual in-band cable tuners and demodulators are used to receive two digital channels for picture-in-picture capability or for outputting two different TV programs to two TV sets.
An optional 200MB hard disk can be used for storage of over 100 hours of video entertainment for personal video recording or later viewing. Content stored on the hard disk can be encrypted, ensuring that the rights of the copyright holders are protected.
A high-speed cable modem can be installed and used for Internet browsing and for downloads of streaming media.
Cable Set Top Box block diagram
