Prepared By: Disha Ruparelia ( ) Pooja Patel ( ) Krupa Rajdev ( ) Misari Thakkar ( ) Guided By: Rohit Sutariya ( ) Rinkal Shah

Digital Television Receiver

What does a DTV receiver do? Receives digital TV broadcasts from a cable, satellite or terrestrial network Decodes them Outputs them to a television or other display device This display device is usually a television May do other things E.g. execute applications included with the broadcast

Types of digital TV receiver Set-top box (STB) The most common type Varies in functionality and features from very basic to very advanced May be integrated with other types of device E.g. a DVD player or PVR system Integrated Digital TV (IDTV) Receiver is built into a TV set Can receive digital or analog broadcasts with no extra hardware

Block diagram of a typical receiver TunerFront-end Smart card / CA Module MPEG-2 decoder CPU Middleware SDRAM Flash memory Graphics processor Descrambler MPEG-2 demultiplexer

The Front End The part of the receiver that actually receives the analog signal and converts it into a stream of bits Two main components, the tuner and the front end These may be integrated into a single package Usually specific to cable, satellite or terrestrial networks Some may support both analog and digital signals

The Front End The tuner Receives a signal on the frequency specified by the rest of the STB Demodulates the signal Turns the analog signal into a digital bitstream The front-end Performs first level of error correction Removes the first level of packetization in the stream Outputs an MPEG-2 transport stream in digital format

The Demultiplexer Takes an MPEG-2 transport stream and locates those elements that the STB is interested in All elements of the current channel Audio and video streams Broadcast data streams Service information Some service information for the network as a whole

The Demultiplexer Passes these streams on to other parts of the system Service information and data streams to the CPU (if it is interested) Audio and video to the MPEG decoder Other data from the transport stream is thrown away But demultiplexer may include section filtering capability to filter other MPEG-2 sections as requested by applications

The MPEG Decoder Decodes audio and video streams and displays them on the screen May include support for graphical overlays Cursor, graphics Some receivers support up to five graphics planes Background, video, two graphics planes, cursor

The MPEG Decoder May include support for scaling, clipping and repositioning video But this may be limited Typically combined with the graphics processor Makes it easier to integrate different elements of the display

The CPU Handles all of the other tasks in the system Decoding and handling service information Decoding broadcast data streams User interaction Running built-in or downloaded applications Often integrated with the MPEG-2 decoder and other components

The CPU Typical CPUs STMicroelectronics 551x family NEC EMMA2 ATI Xilleon Broadcom BCM3560

Conditional access (CA) Anti-piracy system for pay-TV Decrypts some or all of the data Depending what was encrypted by the network operator Usually based around some kind of physical token Smart card or similar device Only that token will work with that receiver Each STB usually has one CA system integrated This is enough for most pay-TV systems The box is tied with the subscription, so only used on one network and one CA system

Conditional Access (CA) Some CA systems require special hardware support e.g. NDS Usually features built into the CPU Most systems will use a standard Smart Card slot Some receivers will use two, one for CA and one for banking card, etc.

Conditional Access (CA) CA systems may do more than just encryption Pair a smart card to a single receiver Smart card can not be moved to other receivers Provide a way of uniquely identifying the receiver Smart card serial number Prevent STBs moving to other household Second STB usually provided at lower price by network operator CA system may stop that box being given to neighbor, friend, other family member Every household must have their own subscription

Conditional Access (CA) Integrated CA systems are unsuitable for some markets May use a pluggable CA module instead Entire decryption solution on a PCMCIA card Smart card plugs in to PCMCIA card Used on retail systems to allow use with any network Common systems include:

Return channel Used to communicate with the network operator or other service operator Ordering pay-per-view services, home shopping, home banking May be used for general network access Web browsing, , chat

Return channel Many types in use PSTN modem (usually 56K) is still the most common Cable modem and ADSL modem are becoming more common Exotic technologies such as GSM, DVB RCS (return channel via satellite) etc. also in limited use Not every receiver will have a return channel Adds to the cost Not all subscription services will need or use one

Middleware Provides a common software platform for application development Usually in C or Java Every middleware platform has basically the same features Graphics & video manipulation, return channel access, access to service information, etc. But open middleware platforms are now being deployed MHP, OCAP, ACAP, JavaTV, ARIB-B23

Middleware Most middleware platforms today are proprietary OpenTV (OpenTV Core) NDS (NDS Core) Canal+ (MediaHighway) PowerTV (PowerTV) Microsoft (Microsoft TV) Nagravision-Kudelski (Tsunami) Liberate (Liberate)

Integration Cost is a major factor in STB manufacture Especially in vertical markets Everyone wants the product cheaper Lots of competition Typical cost is ~100 USD to the network operator for a standard STB Retail is more expensive Many components get integrated to save cost Tuner and front end Demultiplexer/MPEG decoder/CPU/graphics processor

Integration Most current STBs are one- or two-chip solutions Depends on features needed Pressure is always towards more integrated solutions

Conclusion All DTV receivers are fairly similar Most differences are in the software E.g. middleware, CA system Feature sets range from extremely basic to very advanced But most boxes currently sold will have roughly the same features Middleware to provide some interactive applications (e.g. program guide and downloaded apps) PSTN modem or cable modem for return channel

Conclusion The move towards horizontal markets is giving more opportunities for receiver manufacturers Markets are growing Wider range of feature sets can be sold As markets grow, more televisions will include this functionality Just like TVs now include cable as well as terrestrial reception

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