GX3011-Based Hardware Design And Implementation On "HuHuTong" Set Top Box Of Digital Broadcast Satellite

The nation provide the service of Direct Broadcast Satellite (DBS) to live TV programs using ChinaSat nine launched independently by China while receiving signal utilizing the ground receiving equipment, aiming to make those people in remote areas watch TV and listen to the radio for free.The "HuHuTong" Set Top Box (STB) is the ground receiving facility of DBS system, used for transforming and processing signal after receiving it from DBS, which can output signal of audio and video to the display device for users.This thesis mainly studied the related standards、hardware principles and design points of the "HuHuTong" STB of DBS based on GX3011, and completed the design and implementation of its hardware circuit. The main workscan be summarized as follows:1) On the basis of the brief introduction of related standards of DBS, thisthesis studied the working principles of the "HuHuTong" STB with GX3011 as main decoding chip, and analyzed the requirements of the system device and selected important devices. The important devices include GPRS module, Flash module, DDR module, reset chip, audio chip, video chip, and so on. At last, the structure and function of hardware circuit of the "HuHuTong" STB were given.2) Based on above, this thesis proposed the design and schematic diagram of the circuit in detail and achieved the design of the entire hardware system after studying the variety modules of the "HuHuTong" STB’s hardware system such as power circuit, RF circuit, GPRS module, main processor, memory module, audio module, video module, and so on. There into, for power supply circuit, this thesis designed the power distribution program of the powerand selected the power chip and showed the specific parts of the circuit of the powercombined with the design requirements of the system’s power consumption after analyzing the power demands of the hardware system.3) The thesis completed the overall tests of the STB hardware system, including power supply voltage, basic functions, receiving sensitivity and SNR of RF signal, audio and video parameters, voltage sequence of smart card, display of remote control,push-button, and so on. Finally, the test results were showed and analyzed.4) Thisthesis showed the problems in the testing process of STB hardware system and described the fault phenomenon. The solutions were proposed after debugging and testing. These problems includedabnormal start, GPRS module, remote control receiver, abnormalvideo display, video interference, audio noise, LED work abnormalities etc.In addition, during the process of design and implementation of STB hardware system, the ultra-low power consumption under 8 Watts of the "HuHuTong" STB was realized using the power system which adopting the new DC/DC design of single power supply; In the design of RF circuit, "on board design" scheme was adopted in satellite part in order to reduce costs greatly while guaranteeing the system performance; GPRS module adopted the "on board" scheme to avoidthe unreliable factors in module docking for improving the reliability of the system.