DPLC通信中的双数字调解器及其DSP实现

【作者】 李朝海；

【导师】 李晓峰；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2001， 硕士

【摘要】 电力线载波（Power Line Carrier，PLC）就是复用高压输电线路传输载波信号的通信方式，是电力系统特有的一种通信技术。PLC经过长期的发展，已被电力行业广泛应用。但传统的电力线载波都是模拟式的单话音通道结构，在现代通信沿着宽带化、智能化等综合业务方向发展的前提下，PLC面临着频率资源利用、抗干扰特性、数字综合业务接入、智能网络管理和调度等技术方面的挑战。数字电力线载波（Data Power Line Carrier，DPLC）正是由此应运而生的，它克服了PLC存在的某些缺点，改善了PLC的许多特性而倍受重视，并迅速成为国内外电力线载波通信发展的主流方向。 DPLC是利用多种先进技术，将信息转换成数字信号，在电力线上传送的通信设备。DPLC并不直接把数字信号送往电力线，而是先对载波进行调制，形成模拟信号，再向电力线发送。其中基带处理与调制解调部分为DPLC全数字化的核心，本次设计的双调制解调器正是这一核心部分的实现。本文首先从最基本的数据通信系统模型出发，讨论了数据通信的相关理论；然后着重分析了系统的调制解调方案、滤波器的设计以及码元同步技术，基于基带数据信号的零交点中包含有定时信息这样一个原理，我们此次提出了利用过零点信息进行码元同步的方法；最后讨论了基于V.42的差错控制规程以及系统DSP实现时的技术要点。整机采用大规模集成电路，并利用DSP技术来实现DPSK、QPSK数字调制，同时提供平衡四线600Ω变压器耦合接口用于连接载波设备；利用升余弦函数滤波器整理发送信号频谱，满足了载波信道的要求。更多还原

【Abstract】 PLC is the communication means of transmitting carrier wave signal with multiplexing high voltage power lines, which is special communication technology in electric power systems. PLC has been used widely in electric power industry in long-term development. Traditional PLC is single tone channels structure. At the precondition that the modern communications are developing along with ISDN of wide band and intelligence, PLC is facing challenge of frequency resource utilization, anti-intervening characteristic, connection to LSDN, intelligent management of networks and electric power distribution. DPLC just emerge as times require. Because DPLC overcomes some disadvantages of PLC and improves many characteristics of PLC, it is importance and become rapidly the mainstream of PLC communication in world. DPLC is communication system, which converts information into data signals and transmits in power lines by using many advanced technologies. DPLC doesn抰 send data signals to power lines directly, but modulates the carrier wave to analog signals and then transmits it in power lines Modulation, demodulation and baseband signals processing are the core of DPLC, the dual modem we designed just realize the core of DPLC. First, we discusse the relevant theory of data communication from the basal model of data communication systems in this paper, and then stress on the scheme of the modulation and demodulation, the design of filter and the technology of code synchronization in system. Based on the theory that the data of base band embody timing information in zero point of intersection, we put forward the method of code synchronization by using information of the cross-zero point. We discusse the protocol of controlling errors based on ITU-T V.42 and the essential of DSP realization. The dual modem use LSI and realize the modulation of DPSK and QPSK by using DSP technology, and offer the coupling transformer interface of counterpoise four lines, which connects the carrier equipment, and fit in channel by using the root raised cosine-shaping filter.更多还原