毕业设计通信专业相关文献翻译.doc

原文：SYSTEM DESIGN FOR A MINI-TYPE REMOTE MAINTAINING TERMINAL DEVICE BASED ON A TELEPHONE NETWORKABSTRACTThe remote maintaining and diagnosis technology is very important for the distributed and distant on-the-spot equipments and devices for monitoring，predicting，and diagnosing failure．This paper presents a new kind of mini-type remote maintaining terminal devices based on a telephone network．The system design and implementation is described in detail in the paper．The device is composed of a integrated circuit，telephone dial unit，modulation unit，central processing unit，button input unit and display unit．The mini-type remote maintaining terminal device communicates and exchanges information with the distributed and distant on-the-spot equipments and devices for monitoring, predicting, and diagnosing failure．The data is transmitted through the public switched telephone network (PSTN)．It can communicate with remote equipments, gather the various parameter data of the devices such as power, power factor, and frequency from the remote industrial equipments．It can also be used to control the remote devices．In the paper, the hardware and circuit design is described in detail．The device is practically very important for monitoring，predicting，and diagnosing failure with a low total cost．Keywords：remote data exchange device, PSTN, circuit design, DCE1．INTRODUCTIONInformation communication with remote computers or equipment is of great importance in numerous industrial applications and public data services．Many kinds of communication and data-transmitting systems have used data communication equipment (DCE)to exchange information．The special-purpose data communication equipment(DCE)has a important practical role in those systems, because they are cheaper and more convenient than the systems built up by the computer network to form a distributed environment．The DCE call often satisfy the required special-purpose communication system in many special fields．A number of experiments and researches have been done regarding the remote data exchange devices in recent years．Many investigators have explored the special devices that exchange data through public switched telephone network．Reddy reported a device that could transmit data over telephone networks．He proposed the basic principles of data transmission over the Public Switched Telephone Network (PSTN)．Hong Sun investigated a kind of HUST-B remote terminal devices, which consisted of computers and measurement devices．It could communicate with remote equipment；gather the parameter data of power, power factor, and frequency from the remote industrial equipment．It could also be used to control the remote devices．Shuping Mao designed a real-time remote data gathering device based on a Neuron chip and network technologies．Zhiwei Jia reported a device that utilized PC ISA slots．It realized data exchange between a power system and the remote terminalmachines．Hui Huang suggested a system structure of an Internet based radiotherapy diagnose system with some kind of remote devices．Although many researchers have investigated the remote data exchange system with the special-purpose remote terminal devices，little work has been published on the system and circuit design of the data exchange devices that can transmit the data based on public switched telephone network．In this paper, we investigated a mini-type remote data exchange device that can be used to exchange the data with the remote host computer through PSTN．The system principle and the circuit design of the device have been studied in detail．The results of this study may help the design of the PSTN based data exchange devices and the system construction of the general used special purposed communicationnetwork．2．THE PRINCIPLE OF MINI-TYPE REMOTE DATA EXCHANGE DEVICEMini-type remote data exchange devices are considered in a non-industrial field．The public has a great demand to exchange data and information with a remote computer and database in daily life．Such device should satisfy following requirements：1) The data is transmitted through PSTN．2) The expenses age relative low．3)It requires relatively a small size and easy to carry with．4)It can be easily operated and managed without certain training．The mini-type remote data exchange device is used to exchange data with remote host computer’s database when data users are dispersed in different geographical positions．Users can set up a connection remote host computer with a mini-type remote data exchange device．The device can be used at places such as home or a hotel or at any place where PSTN exists，to connect the host computers for exchanging through a telephone line．It would improve working efficiency and reduce expenses．Because digital signals are unsuitable to be transmitted in the paired-line of a public switched telephone network, communication between a user and server must be done by using a modem device to modulate the digit。