The Research And Application Of New PLC Communication Module Based On Low Voltage

Power line Carrier Communication on low voltage makes use of the power network to transmit data and exchange information. It has remarkable advantages that need no new wire, to cover the scope broadly and connection convenience, applied in the development of Automatic meter reading (AMR) system.Carrier Communication module supposed in this thesis is the core chip in automatic meter reading system. Include of high-speed pipelined 8051-compatible microcontroller core, narrowband FM MC3361, peripheral circuit and interface module, it is independently developped by ourselves with full intellectual property.The main content and work in this thesis are as follow:(1) The main carrier chips in recent AMR system are discussed in detail. The transmission characteristic of the power line carrier communication channel is analyzed; the advantages and disadvantages of modulate technologies are compared. The basic principles, performances, characteristics and key technologies of 2FSK and OFDM are stressed, and these systems are simulated with SystemView software.(2) Based on narrow band frequency division modulated theory, the software frequency division method is supposed in the thesis with the integrated mixed-signal system-on-a-chip MCU C8051F300. With high speed performance (up to 25MIPS), this software is compiled to divide frequency, and produce the high frequency, low frequency, and MC3361 local oscillating signal in FSK modulation. Referred to the principle of the intermediate frequency transformer, dual-loop resonant circuit of input signal is constructed to select frequency. And the enhanced, demodulated, reshaped circuits of input signal are designed. The DSP algorithm is advanced, and the digital sampling software is complied to restore the received signal. In order to put down electromagnetic interference, some measures are applied to improve the stability in PCB layout-designs, such as the shorten wire, and the added decoupling filter in power supply.(3)The module is tested, after simulating the complied softwares online. Based on the testing principle of carrier communication module, testing framework is constructed. And testing software of carrier communication module is complied, and some technique indexes are obtained. Coordinated to the outer power supply and the electrical level converting circuit, the intellective functions of modulator and demodulator are realized. And they are applied in the produce region and local testing.