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一、引言 1.数据通过时间扩散信道传输后的符号间干扰过去几年,对于能够有效地利用信道有效带宽的数据通信系统的研究、设计和发展作了很大的努力。设计日的是:以规定的误码率,达到最高的可能传输率。要达到高传输率的主要限制是信号通过带限信道传输时对信号的时间扩散。在数据传输中,时间扩散对发射信号的影响是造成相邻符号之间在时间上重叠,我们把它叫作“符号间干扰”。所有的实际信道都有某种形式的时间扩散,并引起符号间干扰。作为例子,我们以二种类型的时间扩散信道为例。第一种是电话信道,这种信道时间扩散的影响是使其频率响应特性不理想,一般用衰减和包络延迟与频率的关系来表示。理想的信道在其频带内衰减和包络延迟是一常数。因为电话信道的衰减和包络延时特性在其频带内不是常数,所以信号在这种
I. INTRODUCTION 1. Inter-symbol interference after data transmission over time-dispersive channels In the past few years, great efforts have been made to research, design and develop data communication systems that can effectively use the effective channel bandwidth. Design Day is: to the required bit error rate, to achieve the highest possible transfer rate. The main limitation to achieving high transmission rates is the time spread of the signal as it travels through the bandlimited channel. In data transmission, the effect of time dispersion on the transmitted signal is to cause the temporal overlap between adjacent symbols, which we call “intersymbol interference.” All of the actual channels have some form of time dispersion and cause intersymbol interference. As an example, let’s take two types of time spreading channels as an example. The first is the telephone channel. The effect of such channel time spreading is to make its frequency response characteristic not ideal. Generally, the relation between attenuation and envelope delay and frequency is expressed. The ideal channel is attenuated in its frequency band and the envelope delay is constant. Because the attenuation of the telephone channel and the envelope delay characteristics are not constant over its frequency band, the signal in this