The Research And Design Of The Embedded Mine-used Broadcast Talkback System

Mine-used broadcasting system considered as the one of the importantcommunication systems plays a very important role in coal mine production. But dueto the complex environmental impact of coal mine underground, the available minebroadcasting systems exist many problems in practical application. Based on theanalysis of the features of the public broadcasting system and the demerits researchfor the existing mine talkback system, the design based on embedded system for mineintercom system was put forward.On the analysis of functional requirements and design goal, combined with thedesign principles and requirements for the intrinsic safe circuit, the design selectsARM processor S3C2440A, Window CE system as the software platform and theRS485bus which is low cost, long-distance transmission as the speechcommunication method construct the Embedded mine broadcasting and intercomsystem.Meanwhile, in comparison with various existing speech compressionalgorithm, we choose the G.729coding and decoding algorithm with coding rate8kbit/s. After further research on the coding algorithm, the LSP vector quantizationalgorithm and adaptive codebook search algorithm that occupy vocoder large amountsof time and resources are optimized.The simulation results indicate that thecalculation of optimized G.729codec algorithm reduces more than that of the originalalgorithm, while the voice quality remains basically unchanged.The hardware design for the control substations includes mainly: UDA1341TSaudio processing module, LCD display module and audio amplifying module.According to the hardware platform, the operating system of WinCE with thedesigned audio driver is transplanted to the system.The monitor program for mastercontrol station, the terminal application program, as well as the speech processingprograms consisting of the audio collection, speech coding and speech playback forall the stations was compiled.Mine-use broadcasting intercom system was built up.The serial communication,speech acquisition and speech coding algorithm was tested.The test results show that when the system works normally, after optimized coding and decoding algorithm theaudio output sounds well. In this paper the system with small volume and better voicequality realizes reliable transmission, which provides a convenient and realcommunication between the underground employees and the control center.