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SetSet -- Top BoxTop Box(STB)(STB)

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What is STB?What is STB?y It is an electronic device that is connected to a

communication channel, such as cable television

line and produces output on a conventionaltelevision screen.

y Set-top boxes are commonly used to receive anddecode digital television broadcasts and to

interface with the Internet through the userstelevision instead of a PC.

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y A

set-top box or set-top unit is a device thatconnects to a television and an externalsource of signal, turning the signal intocontent which is then displayed on thetelevision screen or other display device.

y A

set-top box is the device that connects atelevision to a cable signal or satellite signalreceived from a service provider.

y A typical digital STB contains one or moremicroprocessors for running the operating

system, it also includes RAM

,M

PEG decoderchip, and more chips for audio decoding andprocessing.

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y Set-top box technology has evolved with the in creasing demand by consumers for television andrelated services such as e-mail and video on

demand.

y The First Generation set-top box had a simplefunction. It received an encoded analog television

transmission from the service provider, decodedthe signal, and sent the decoded signal to thetelevision.

HistoryHistory

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y The next generation set-top box allowed two-way

digital transmission between the service providerand the consumer.

y A digital incoming signal from the serviceprovider contained the television signal, and theoutgoing signal from the customer carried

requests for service, such as pay-per view accessto programming.

y The latest in set-top box technology enablesservice provider to offer fully interactive servicesthat include video on demand, interactive

advertising, TV-centric applications, email,videoconference, and Internet access.

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Hardware ArchitectureHardware Architecture

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SetSet Top Box HardwareTop Box Hardware

ArchitectureArchitecturey Requirements based on functionality.

Should have MPEG-2 sub-system to decodeMPEG-2 video and audio.

Should enable user to download customapplications and execute them on the STBwhich requires a general purpose

microprocessor in the STB with an architecturethat supports control of the different devices.

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STB SoftwareSTB Software

Driver Adaptation Layer

Middleware

Device Drivers (Manufacturer)

CAS

Application Layer

Loader

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STB Software ArchitectureSTB Software ArchitectureFor personalized interactive services, a set top boxshould be addressable in the video dial-tonenetwork, thus providing P2P communication

between a video and information provider and auser. It should also have the ability to downloadclient applications and execute them locally.

The control software on the set top box ties

together all the hardware components into afunctioning unit.

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y STB software has two parts. System software which provides the DAVID application

programming interface. Application software that provides cable TV functionality

or some other personalized multimedia service.

y DAVID system software includes. Operating system(os-9) kernel. Device drivers. File manager.

y Operating system(os-9) kernel is responsible forthe following:

x Scheduling different tasks for the microprocessor.x M

anaging inter-process communication betweendifferent tasks and processes in the STB.x Memory management for the multi-tasking operating

system.x Maintaining the real time clock for the system.

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yDevice driversThe various hardware components of STB have

programmable registers that can be used to control thebehavior of the components. Each one of these devices has adevice driver task associated with it that allows the mainmicroprocessor to manage the device. The device drivers alsoperform interrupt servicing for the components and hide the

details about device addresses and actual register values.

yFile manager File manager available for each device driver and

provides a file like interface for the device.

file like interface provides a uniform layer of abstractionand is generic to all the capabilities of STB.

RTNFM, SPF, MPFM, AUXMAN.

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y There are three categories of set-top boxes:broadcast TV, enhanced TV and AdvanceServices.

y A broadcast TV is also known as Thin-boxes,broadcast TV set-top box provides traditionalbroadcast television and has no return channel.Signals are received in MPEG-formatted dataStream.

y These might come with interface ports, somememory and some processing power.

Types of Set top boxTypes of Set top box

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y An enhanced TV set-top box is similar to abroadcast TV set-top except the enhanced TVset-top box has a return channel from thecustomer to the service provider.

y These may be capable of Video on Demand, e-

commerce, Internet browsing, e-mailcommunications, chat and more.

y An advanced services set-top box is alsoknown as advanced digital set-top box.

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y An advanced services set-top box is

basically a dedicated personal computerthat has sufficient computing power toprovide rapid processing for interactive,multimedia services.

y These have good processors, memory,software applications and optional hard-drives. They're often used with high-speed(broadband) connections. Features could

include high-speed Internet access,Interactive TV, digital video recording &gaming.

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ConclusionConclusionFor the hardware there will be strong trend towardsvery flexible decoders in the form of signal processors

and fast CPUs possibly even combined with evencombined in one large digital processing CPU. Thearrangements for sending information fromterminal(STB) into the network can be improvedboth in latency and in throughput. The graphic

subsystem is likely to grow towards 3D applications.

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Conclusion (contd.)Conclusion (contd.)STB software hides the machine and networkspecific features of a set top box under a layer

of abstraction and provides a user friendlyinterface to access cable television and videoinformation services. The software componentsare likely to increase with more integrationand more programmable components. This

will increase the flexibility of STB.

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interoperability of software.

Navigator. Downloaded applications.

Operating system upgrade.

Other resident applications: config,

display

ApplicationsApplications

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ReferencesReferenceshttp://en.wikipedia.org/wiki/Set-top_box

http://www.hathway.com/dctv/setbox.htm

http://focus.ti.com/docs/solution/folders/print/262.html

http://www.becil.net/pdf%20docs/digital_%20set_%20top_%20box.pdf

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