| Train emergency intercom system which is an integral part of the train passenger information system, provides audio communication for the driver and passengers in emergency situations. With requirements of service quality increasing, and the train emergency communications equipment based on the MVB can not meet the requirements for communication, so the train emergency intercom unit needs further improvement.This thesis designs a train emergency intercom unit based on TI's TMS320DM368. It uses Ethernet to communicate and provide Ethernet Bypass function. And it can deal with audio and video information through audio block and vedio block. This thesis also has emergency intercom button indication module which can provide reliable service for passengers and drivers. This plan can be verified through Block diagram of the design, component selection, schematic and PCB design and functional tests.This thesis firstly introduces the Train Communication Network and this design's background and significance. By the analysis of the requirements of train emergency intercom unit, the key chip is selected, and the design plan based on DM368+FPGA, TLV320AIC23 audio codec chip, KSZ8863 Ethernet chip, TVP5150 video decoder chip is also selected. Subsequently, this thesis details the circuit design of DM368+FPGA module, audio module, video module, Ethernet module, power module, emergency intercom button indication module and other major functional modules. After that, according to the requirements of the electromagnetic compatibility and signal integrity in PCB design, this thesis provides the design of the PCB stack selection, placement, routing, signal topology of DDR2 and other aspects, this thesis also gives a brief introduction for postprocessing of PCB design. Next, this thesis introduces the test work of hardware and function for train emergency intercom unit, and analyses the corresponding test results. Finally, the conclusion is discussed and the future work are discussed. |
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