The Design And Implementation Of Digital Language Learning System

The digital language learning system is a set of professional teaching equipment and software together. It has many characters and advantages, such as digital signal transmission and storage, sharing resource on network, friendly human-machine interface and so on. Currently, the digital language learning system has become the main development tendency of the language teaching equipment or system. This thesis details the analysis and research on the main-structrue design, communication ptorocol, hardware design an software development of the digital language learning system.The first chapter analyzes the technologies and development trend of the digital language learning devices. The second chapter introduces the development technologies used in the system in detail and especially design the audio communication protocol. The third chapter proposes and designs the overall structure of the digital language learning system. The fourth chapter details and analyzes the research and implementation of the system. The fifth chapter demonstrates the instance of the developed system and analyzes its function modules.The system designed and developed in the thesis consists of five parts:student terminal subsystem, main switch, minor switch, computer adapter card and host PC system. The student terminal subsyste is one of the key components. The digital student subsystem can be divided into three functional units:transmission interface, human-machine interface and speech processing units. The Speech processing is the core unit and it mainly achieves speech collection, audio compression and decompression, and audio files playing. Human-machine interfacce unit has keyboard and LED displayer, providing easy operational interface for students. The transmission interface unit completes data transmission between minor switch and the student terminal subsystem. The MyProtocol is design and implemented in it. The host computer works as the network server and is responsible for the request sent by the student terminal subsystem. The adapter card, main switch and minor switch constitute the data channel between host computer and student terminal subsystem. According to the characteristics of speech signal and its transmission, the thesis also optimizes the overall systemdesign. Especially in the switch set, the principle of speed and area inter-change is employed. Thus it reduces the resources of the system and also ensures the continuous data flow. The digital language learning system has been produced in large scale and widely applied in foreign language teaching.