The Research And Implementation Of The Digital TV Set Top Box And Its Man-machine Conversation

It is impossible to eliminate analog TV immediately in the transitional course of the TV broadcasting development from analog mode to digital mode. Digital TV Set Top Box is the best solution in the transitional course.STx5105 platform is the Digital TV Set Top Box solution provided by STMicroelectronics Inc. (ST). OS20 real time operation system is used in the software system. The RTOS is multithreading and multitask, which enhances the ability of real time processing and provides the platform for abundant user functions. The core of STx5105 is STV0297 and STx5105: STV0297 receives the digital TV signal, QAM demodulates later, samples the TV signal from cable at intermediate frequency and then converts to MPEG-II transport streams. STx5105 has a ST20 32-bit CPU core inside it, and can receive the MPEG-II transport streams from STV0297 through external interface. What's more, STx5105 has many functions, such as audio and video decoding, picture zoom, ADC and so on. In addition, STx5105 can be used to provide the fire-new wonderful user menu because of its own Blitter display engine and Picture Compositor (mixing four planes).This dissertation introduces system design (software and hardware) of Digital TV Set Top Box based-on the STx5105 platform, OS20 embedded operation system, the layer and module of the system software, the relationship and communication methods among modules, and the software flow of power on and normal working. Especially, this paper introduces the criterion of the function of Set-Top Box, the frame of GUI, and communication between GUI and the other parts, the arithmetic of smart spell input method and realizing it into program, playing music with logo and so on and also introduces the debug methods of the system.Digital TV Set Top Box enhances the picture quality, increases the user function, easy to realize intelligent and popularization. During the time when analog TV is transforming to digital TV, Digital TV Set Top Box will attract more development in TV industry.