Research And Implementation Of Modem Of Power Line Communications Based On ARM

Power Line Communication(PLC)is a technology which sends data over power line networks.According to the voltage of power lines,it can be divided into high-voltage PLC,medium-voltage PLC and low-voltage PLC.Currently low-voltage distribution network is the physical network with highest entry rate which has a broad application prospect because of good expansibility and wide coverage.However the complex topology and the noise interference increases the error bit rate of the PLC.So,it is very significant to develop reliable,efficient,fast and low cost PLC.Meanwhile,the spectrum resource is more and more scarce.The Ultra Narrow Band(UNB)efficient communication can achieve higher baud rate with narrower band.The noise can be filtered by using a band pass filter.Therefore,the application of the UNB modulation in PLC will be of great commercial value.The major result of this thesis is to research and implement a PLC modem based on ARM with UNB technology and guarantee reliable communication and reduce overall system cost as much as possible.First of all,this thesis analyses and models the channel characteristics and the channel nosie of PLC.Secondly,it covers efficient modulation and the impacting filter.The impacting filter is a special filter which can convert the changes of phase into the changes of amplitude.Finally,three demodulation schemes have been proposed and the advantages and disadvantages of all schemes have been analysed.Meanwhile,An algebraic explanation for Maximum Decision supports schemes.All processes about researching and implementing system are given in the thesis.