Introduction In China, digital TV programs in many provinces and cities have begun pilot, because the client is using the basic analog TV, can not receive digital signals, so need a receiver to act as a bridge between the two, which is the set-top boxes (SetTopBox, referred to as STB). It is an expansion of TV features a new household appliances. It can broadcast digital television signals, satellite, terrestrial digital TV signals, cable television or the Internet digital signal digital signal converted to analog TV can receive a signal, so that existing analog TV users to share digital revolution brought scientific and technological achievements. The article introduces the author developed based on DVB-C cable digital TV set-top boxes.
DVB-C hardware design of digital set-top box
LSI2005 main chip introduced DVB-C digital set-top box using LSILogic company SC2005 as the main chip. SC2005 using the latest 1.27mmPBGA package will LSIL641x8 transmission L64105MPEG-2 decoder and audio and video decoder integrated in a chip, the high integration, built-in industry standard TinyRISC108MHzMIPSCPU, 5-layer graphics engine, DMA controllers, and unified The OSG memory and A / V memory; integrated a number of standard encoders, can be independently programmed video DAC, audio DAC.
SC2005 from the channel decoder to receive the TS stream before being delivered to the internal L641x8 module by L641x8 demultiplex the data to form audio and video PES packet data, via A / V interface output to L64105MPEG-2 decoder to decode. L64105 decode the PES packet, the output of digital video and digital audio signals of all groups. A set of digital video and a digital audio signal directly output. Another group of digital video signal to the video encoders, is converted Shing Chuen TV signal (CVBS) or S terminal signal (Y / C), through an external low-pass filtering, can be sent directly to television sets. Another channel digital audio signal to the audio DAC, the analog signal into a stereo via an external low-pass filtered output.
SC2005 offers a variety of peripheral interfaces, including two UART interfaces, two smart card interfaces, I2C interfaces, IEEEl284 interface, infrared interface, Teletext interface, general-purpose I / O control, and modem interface. Through these interfaces, SC2005, and a variety of peripherals can be connected to its more powerful. In addition, SC2005 and a hard disk interface, programs can be downloaded to the hard drive, look after.
DVB-C set-top box hardware design Order to achieve the functions of cable digital STB, from technology to meet the following requirements:
(1) to receive CATV network in the frequency range 110MHz ~ 855MHz RF signal, and converted to IF signals.
(2) solution to achieve QAM modulation, the modulation signal restoration for the digital baseband signal.
(3) complete the channel decoding processing, forward error correction function to achieve.
(4) complete the TS transport stream demultiplexing, MPEG-2 decoding, and can achieve television signal decoding and audio DAC functions to meet the requirements of the analog output audio and video signals. I am an expert from China Crafts Suppliers, usually analyzes all kind of industries situation, such as hino dump truck , mini dump truck.
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