The design of nuclear subsystem in Ti digital set

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Analyze the design of the nuclear subsystem in Ti digital set-top box

the digital set-top box (STB) is connected with the TV and external sources to convert the signal into the content that can be displayed on the TV screen. With the addition of hard disk drives (HDDs), the set-top box solution can also support PVR (personal video recorder) functions. This paper will detail the kernel subsystem design of STB

design considerations

digital set-top box (STB) is connected with TV and external sources to convert signals into content that can be displayed on the TV screen. With the addition of hard disk drives (HDDs), the set-top box solution can also support PVR (personal video recorder) functions. A common independent component called TiVo is an example of PVR. Like many home electronic terminal devices, remote control is an important component of a complete system. Many consumer products begin to use RF remote control with the help of RF4CE scheme that ti is leading. These devices depend on the low-power RF chips and microprocessors on the remote control and STB

generally, digital STB (PVR) can be divided into several main components; Digital media processor, audio decoding and processing, video decoding and processing, tuner, audio and video output, IrDA or LPW remote control, various interfaces and power supply. Ti's product line has introduced many integrated circuits that can achieve the expected performance levels. Making full use of high-performance audio-video codecs, graphics acceleration, communication and support for integrated applications in the home entertainment experience is critical

block diagram of the nuclear subsystem in Ti digital set-top box

the core subsystem includes:

digital media processor ti's digital media processor can handle complex processing functions such as decoding, transcoding/encoding (converting from one format to another) and the conversion of various media streams (adjusting the higher bit rate to the lower bit rate). In addition, it also meets system level functions such as decryption, encryption, packetization and media stream transmission. In addition to broadcast content, Ti based set-top boxes can seamlessly support content from home networks or directly from Internet. Ti's fully programmable devices achieve rapid compatibility with new codec technology (for all Internet sites or PCS), including future versions not foreseen at the time of product design. Ti's media processor series is software compatible, which means that the degree of soft automation is not high, and the investment can be reused in various products from SD box to HD box, and then to other products, thereby reducing development time and cost

RF demodulation - cofdm/qam/qpsk/atsc demodulation, forward error correction (FEC) and video demultiplexing

msp430 microprocessor in MCU STB is widely used. Through the control and application of multiple different working modes, it can be applied to all ranges from the management and remote control of the interface that also becomes the country with the largest consumption of logistics packaging resources to the management of STB component power consumption. MSP430 can extend the battery life of remote control. No matter which working mode is adopted, it can significantly reduce the power consumption of STB, while hardly increasing the complexity of the system

video interface - select the video source decoded/encoded by adc/dac and DSP. Both video front-end and output stage need high-performance operational amplifiers to amplify video signals. For this terminal device, it is very important to support a variety of ATSC DTV formats, ntsc/pal, composite video and s video. Once HDTV becomes the mainstream standard, products supporting 1080p Full HD resolution with 3D adaptive filtering will be everywhere

audio interface - allows audio to be digitized by audio converter and processed by DSP to provide high-quality audio to meet the requirements of mpeg/ac3. The audio is also converted back to the analog format, and then the tensile strength and plastic characteristics of the material can be measured through the tensile test. It can be played through the stereo output jack for stereo headphones. With functions such as high SNR (signal-to-noise ratio) and analog low-pass filtering, high-quality audio output is guaranteed

the user interface enables the user to control the video/audio i/o source and communicate with the system network at the same time. The user interface also includes a connection to the remote control through IrDA or low-power wireless devices residing on the component itself and the remote control component

broadband and wireless connection - allows interactive TV, games, streaming audio and video, voice over IP (VoIP) and video to be sent and received through ADSL, cable modem, modem and 802.11 interface in the rapid development of new material industry in East China

power conversion includes the AC to DC conversion of creating the main power supply for the component itself. Almost all function blocks in STB need a special power solution; For the core and i/o power supply of the main processor, DDR memory, and the power supply and video/analog signal chain of the tuner. However, in this era of energy conservation, the government has continuously promulgated new policies on standby power consumption and the efficiency of consumer products and strengthened the implementation of existing plans. Almost all current plans to regulate STB are voluntary, but the implementation of mandatory requirements is imminent

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