Research And Development Of Power-line Communication System

With the development of communication technology, more attention has been paid on PLC (Power Line Communication). The range of power line is wide. It has been set in many kinds of buildings. Thus, it is fit for the data communication between multi-terminals in the specific area, not only makes the install process easier, but also saves the investment of the project. A narrow-band communication system based on FSK. is proposed in this paper, and a multi-computer communication system is developed based on this method which is fit for the numerical reading system and the temperature-collecting system.The power line is a bad environment to carry signal and not suitable for transmitting signal because of its characteristic which includes high load, serious disturb noise and attenuation in the channel. Thus, the disturb noise and attenuation characteristics of the power line had been discussed in-depth before designing this system. The theory characters of FSK had also been described in-depth.Based on the analysis of channel characteristic, this paper introduced the system structure and the operation mode in-depth, and proposed the holistic idea of design. This is the most important part in this paper, including the design of hardware circuit and the development of communication protocol. The design of hardware circuit had two main parts, one is the hardware circuit of receiver and the other is the hardware circuit of transmitter. The design of hardware circuit includes the interface of power line, signal amplifier, model and controller. Except of the design of hardware circuit, the communication protocol was also proposed and developed. At the same time, through many times of the experiment analysis, a data-processing method suitable for the system was designed, this is the characteristic part of this paper. A pretreatment of the transferred data with specific software is made to make sure that the hardware system's efficiency greatly improved during the course of modulation and demodulation, and achieves a consummate combination of the software and the hardware at last.At last, the design of the system hardware circuit and the exploitation of the communication protocol are completed, an integrated, applied system of power-line communication is designed, through large numbers of experiments the security and reliability of the system is validated.