Development Of Double Frequency Receiving Digital Television Terminal With Recording Function

The digital TV system is the system based on digital signal, in detail, it include signal emission, transmission and reception. Because of its good feather about The digital signal is popularly used in TV system. The digital TV signal include terrestrial signal, CATV signal and satellite signal. The frequency of terrestrial signal is from40to950MHz, the main feature of terrestrial include short transmission distance and easy technical design. The frequency of satellite signal is more than1GHz, the main feature of satellite signal include long transmission distance, easy affect by the weather. If terrestrial receiving and satellite receiving are included in one system, the system ability will increase, and more and more popular used. At the time, with the development of society, more and more requirement of PVR is needed, PVR is the function of recording the program into HDD or other storage device, the program can be playback, and the user can enjoy it. Because the digital signal is easy saved without distortion, so during digital signal stage, the record function is used more and more popular, in the digital TV system, because the signal is digital format, it can be save in the storage device Without distortion. For this reason, the PVR function is used more and more popular.In this thesis, the design of a TV system based on the microprocessor MN2WS0270is presented, and the key circuits in-depth are also studied. The main works are as follows:1. Making a research of terrestrial and satellite receiving TV system, and by using ARM hardware structure, a TV platform is built. Comparing with other chipset by function, cost, etc, Using the microprocessor MN2WS0270as the key chip, the MN2WS0270is a full function TV process chip, the function of it include demodulation, decoding, demultiplexing, supporting IQ/IF/TS input, supporting full-HD LVDS output.2. Hardware design of system is investigated and the design of key modules is studied deeply. The circuit diagrams and the principle analysis of power circuit, crystal circuit, reset circuit, memory circuit and other input/output interface circuits are given in this thesis. Basing on this, introduce the innovation point of circuit, such as DC-DC circuit and OC protect circuit. Then, the problems encountered in circuit design and some typical cases are also introduced. Finally, hardware system is built, and the product is showed by double frequency receiving and PVR. 3. The thesis introduces the signal processing flow of the Digital TV including RF signal processing, video/audio signal processing. And the structures of the function modules are described. The Linux software structure is used, and the AAC,MP3,WAV,AC3,etc audio type, the MPEG2,MPEG4,H.264,etc, video type is supported.The product with this solution comes true at the beginning of2013, because its good feature, the sales quantity is more than100k, it has a good economy benefit. At the same time, the dual-frequency function improve the ability of using, it get a good social benefit.