Research Of Coal Mine Digital Voice Broadcastingsystem Based On Ethernet And CAN Bus

Voice broadcasting system plays a vital role in the daily production, equipment installation, commissioning, maintenance and the disaster relief process of coal mine.The voice broadcasting system can timely guide the worker to leave the coal mine when the accident happens.Currently, coal mine voice broadcasting system with the limitations often can not carry out half duplex and duplex communication, such as the constant pressure broadcasting, dispatching telephone etc.. According to the shortages of coal mine voice broadcasting system, the subject is about the research and design of coal mine digital voice broadcasting system based on Ethernet and CAN bus.The system can not only initiate the whole network emergency broadcasting and guide scientific hedging at the time of the accident, but also can be used as a powerful tool for connection and enrich the cultural life of the worker in the daily production.According to the application characteristics of coal mine voice broadcasting system, the subject uses Ethernet, CAN bus and embedded technology to construct a set of digital voice broadcasting system. At first, the thesis introduces the current research situation of Ethernet and CAN bus for voice transmission and the key technology of voice transmission, and proves the feasibility using Ethernet and CAN bus to transfer audio. Then the whole scheme of the system, functional requirement and hardware of the audio server and broadcasting terminal(master station and substation) are described in detail. According to the characteristics of Ethernet and CAN bus protocol, the M/D/1 queuing mathematical model for voice transmission system is constructed.It is simulated by MATLAB and the simulation results are analyzed in depth. The work principle and the design process of the dynamic and static buffering control mechanism are discussed according to the real-time characteristics of audio transmission.And the thesis tries to put forward a kind of adaptive de jitter synchronization strategy based on tone quality control.Finally, the design process of the audio server and the software of the broadcasting terminal are discussed in detail based on VS2010 and μC/OS-II.The thesis makes full use of the hardware to carry out the experiments including streaming media playing, single directional, bidirectional, multiple and multiple bidirectional voice transmission. All of the experiments verify the correctness of the related control theory, the software and hardware.