Research On Method Of Low-Voltage Power Line Communication Based On Frequency Hopping Technology

Using the existing low voltage power line to transmit data has broad application perspective and economic benefits. Point to the heavy noise, strong attenuation, which threat the safety of date transmitting on the low voltage power line, this paper present conjunct the power line communication system with frequency hopping technology, to raise the system's anti-interface ability.Firstly, the background and purpose of this subject is introduced, and the present state of PLC and FH system is discussed in this paper. A PLC system based on FH technology is presented here.Secondly, on the basis of practicable measurement, low voltage power line channel character is analyzed, power line channel model is established, and the low voltage power line channel character between 10 kHz and 1 MHz is simulated.Thirdly, the principle of FH system and its key technology is studied. According to the character of power line, a PLC-FH system and its model is designed. Frequency hopping communication on the low power line channel need some changes on FH itself. Using direct correlator instead of heterodyne detection, the sample rate is reduced and the filter design is simplify in this paper. Combing the FSK modulation and the frequency synthesizer, letting frequency modulate directly done by the data, the software and hardware designing is simplified.By means of theoretical derivation and simulation, a conclusion is arrived: the PLC-FH system has good anti-interface ability, the system wouldn't corrupt with some frequency point been polluted.At last, this paper present a system realize solution based on DSP and FPGA, some function is also been designed.