New cable management module of digital set-top boxes – Digital TV, Cable TV, set
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1 Introduction
<BR> Analog cable TV digital set-top boxes are used to receive digital TV programs, to provide broadcast and interactive multimedia applications terminals. Recently, with the digital media business and the rapid development of Internet networks, the new digital set-top box can use our enormous resources in the cable television network, complete video on demand, digital television receivers, IP phone and access Internet and other network integrated business functions. The digital set-top box to decrypt a single charge has been previously installed into Annals compression, modulation and demodulation, decryption, and interactive control as one charge of digital transmission and terminal equipment.
<BR> New digital set-top box to the number of family businesses to integrate with a device to meet the future needs of home users. But since their complexity, there are many new technical challenges, such as: how to effectively coordinate and manage digital TV, IP phone, Internet connection and other integrated services; present, many set-top boxes are one-way or return through telephone lines, and how video on demand and other new services and so on. Therefore, we need to select the higher frequency, data throughput, with broadband interactive features and cost-effective processing chip and the low quality software platform to complete the Management Module.
<BR> 2, program design and chip select
<BR> First conducted a needs analysis of digital set-top boxes, digital set-top box through to home users, while providing Internet access, digital TV and IP telephone services, and can carry a wealth of value-added services. Interface mode based on business needs and the new digital set-top hardware architecture modular design, including the external Ethernet interface module, the internal Ethernet interface module, analog subscriber line interface module, audio and video decoding module and the central management module. External Ethernet interface modules and Ethernet interface between the external network, internal Ethernet module provides indoor computer's Ethernet interface, analog subscriber line interface provides two analog telephone interface; audio and video decoding module provides decoding output of the way digital TV and related interactive features; management module is responsible for the business flow and interface protocol conversion. First, the external Ethernet interface to receive external routers or switches forward the data frame, the solution will be packaged, transferred to the network processor diversion by three kinds of operations; audio and video decoder to receive the main control chip processing module after the TS data stream diversion , for MPEG-2 decoding, the output to PAL / NTSC encoder, encode analog television signals; internal Ethernet interface to receive IP data packets, encapsulated into MAC data frame sent to the computer terminal; IP call processing module through the CODEC codec digital signal and analog chips to complete the conversion and rushed to analog voice phone.
<BR> In the design of this article, the central management module to complete the IP phones (voice), the family line (Integrated Data Service) and digital television (video business) 3 business gateway function. After analysis and comparison of selected Samsung products S3C4510B ARM7 family as its main processing chip. S3C4510B for embedded applications is a 16/32 bit embedded processor, the micro-controller for Ethernet hubs and routers, communication systems are designed with low cost and high performance characteristics, it is built the ARM-designed 16/32-bit ARM7TDMI processor can execute 32-bit ARM instructions, but also perform 16-bit THUMB instructions, and integrates several external components. S3C4510B system clock frequency to 50MHz, 8 kB of Cache / SRAM, 4MB of Flash for storage of boot code, embedded operating system and application software. The management module in the design, S3C4510B through the system bus is connected with an FPGA chip XC2S30. XC2S30 and dual-channel VoSLAC (Voiceover broadband Subscriber Line Audio? ProcessingCircuit) chip Le78D11 connected, Le78D11 and dual-channel VoSLAC chip Le77D11 connected two analog subscriber line extended out the RJ11 interface for connection of two analog telephone. S3C4510B two UART, one with audio and video decoding module cross-connect serial cable to provide a simulation of the SLIP link; another UART MAX232 extended through a DB9 interface for the control of the terminal management module interface, the interface debugging and fault detection system is useful. S3C4510B with JTAG interface for system debugging and FLASH programming online simulation and so on.
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