【作者】 曹尉青；

【导师】 王文理；

【作者基本信息】 河北大学 ， 通信与信息系统， 2003， 硕士

【摘要】 近年来，在我国通信技术的发展势头十分迅猛。以电路交换和数字程控交换技术为基础的电话网更是在整个通信网中占据着重要的地位。本文结合课题首先介绍了程控交换机的发展状况，对模拟交换机和数字交换机进行了性能比较，并指出未来数字交换机的发展方向。然后详细介绍了实现交换机由模拟向数字转变的关键技术——脉冲编码调制(PCM)技术的原理。第三章具体介绍了本设计的硬件电路，对主要功能模块结合功能框图进行了分析，并对设计用到的专用芯片如语音处理AM79C03、交换网络MT8980D等进行了说明，给出了与单片机的接口电路。尤其对于收号器MT8870的使用、信号音的产生电路是本设计的难点，具有数字程控交换的特点，需要占用PCM时隙来完成其功能。第四章是整个电路的软件设计，用来完成用户之间的呼叫处理过程，实现用户之间的通话。本文给出了详尽的设计流程。 本文完成了数字交换机在局域网内功能的研究，并完成了硬件电路的设计与实现，达到了设计目的。更多还原

【Abstract】 In recent years the communicating technology has advanced rapidly in our country. The telephone network based on circuit-switching and digital program controlled exchanging technology plays an important role in the whole communicating networks. The text firstly introduces the status of the program controlled exchange, and compares simulative exchange with digital exchange in the performance, and points out the developing direction of the future digitalexchange. Then the text describes the principle of the pivotal technique-Pulse Code Modulation (PCM) in detail which realizes the conversion of the exchange from simulation to digital. The third chapter introduces the hardware and analyzes the primary function modules with the function diagrams, and illuminates the uses and the interface with the singlechip of the special chips such as audio processing circuit AM79C03, digital switch MT8980 and so on. The difficulties of the text are the use of the integrated DTMF receiver MT8870 and the signal generator circuit. Their realities need occupy the PCM timeslots. They are the characters of the digital program controlled exchange. The forth chapter is the software design which deals with the telephone call between the users and implements the transfer of their voices.The text provides the detailed program flow , and completes the research and the hardware design of the digital program controlled exchange in local area network.更多还原