时间拉伸式光电模数转换器及其并行多通道特性研究

发布时间：2019-02-24 13:53

【摘要】：当今数字信号处理技术已有长足的进步,相比之下,模数转换技术的发展相对迟缓,逐渐难以与之匹配。传统的电子模数转换技术由于其采样时间抖动和比较器模糊等瓶颈,难以更进一步,人们把视野放在了新型的光电混合模数转换器上。时间拉伸式光电模数转换器旨在利用待处理模拟电信号在光域内的特殊性质对其进行预处理,以实现使用低速电子模数转换器对高速模拟信号进行模数转换的目的。具体地说,首先利用光脉冲在光纤传输中的色散展宽原理,将光脉冲展宽到一定宽度,使得能够将待处理模拟电信号强度调制于其上,再使用另一段光纤继续使其色散展宽,则调制于其上的模拟电信号随之一同被拉伸,随后将此光域信号转换到电域,便可得到待处理信号的“降频”输出,进而成倍增强了现有电子模数转换器的有效采样速率。本文的数学推导描述了时间拉伸模数转换技术具有的光脉冲包络去除、功率代价等困难,据此给出了上述问题的解决方案;并进行了数值仿真实验以模拟该类模数转换器的工作过程,首次根据数值仿真分析光纤非线性效应对系统的影响以及通过冗余信号实现在线自适应矫正等问题,分析结果将用于指导实际系统的设计与实现。为解决该系统中功率代价的问题,本文创新性地提出一种在使用单边带调制的基础上的相位矫正方法,以同时保持信号的输出功率以及相位特性,数值仿真结果验证了该方法的有效性。由于脉冲交叠的原因,单通道该类模数转换器仅能用于处理时间离散信号,而要处理时间连续信号,需引入并行多通道处理。因此从器件使用上看,并行多通道时间拉伸模数转换技术相当于使用多个低采样速率的电子模数转换器来构成一个高采样速率的模数转换系统。本文通过系统设计,在实验上实现了该类模数转换器的功能。首先,设计一个单通道的10倍时间拉伸系统,并得到无光脉冲包络的输出结果。进一步地,设计一个并行多通道的4倍时间拉伸系统,完成该系统的搭建,得到了无缝拼接的光载波,可对时间连续信号做处理;并相应得到和分析了各个通道的时间拉伸信号输出。
[Abstract]:Nowadays, digital signal processing technology has made great progress, in contrast, the development of analog-to-digital conversion technology is relatively slow, and it is gradually difficult to match it. Because of the bottleneck of sampling time jitter and comparator blur, the traditional electronic analog-to-digital conversion technology is difficult to go further, so people put the field of vision on the new optoelectronic hybrid A / D converter. The purpose of the time-stretched photoelectric A / D converter is to preprocess it by using the special properties of the analog signal to be processed in the optical domain, so as to realize the purpose of using the low speed electronic analog converter to convert the analog signal at high speed. Specifically, first of all, by using the principle of dispersion broadening of optical pulse in optical fiber transmission, the optical pulse is broadened to a certain width so that the intensity of the analog electrical signal to be processed can be modulated on it, and then another section of optical fiber is used to continue to widen its dispersion. Then the analog signal modulated on the signal is stretched together, and then the optical domain signal is converted to the electric domain, and the output of the signal to be processed can be obtained, which multiplies the effective sampling rate of the existing electronic analog-to-digital converter. The mathematical derivation of this paper describes the difficulties of optical pulse envelope removal and power cost in time stretching A / D conversion technology. Based on this, the solutions to the above problems are given. Numerical simulation experiments are carried out to simulate the working process of this kind of analog-to-digital converters. According to the numerical simulation, the influence of nonlinear effect of optical fiber on the system and the on-line adaptive correction by redundant signals are analyzed for the first time. The analysis results will be used to guide the design and implementation of the actual system. In order to solve the problem of power cost in this system, a phase correction method based on single sideband modulation (SSB) is proposed in this paper to maintain the output power and phase characteristics of the signal simultaneously. The effectiveness of the method is verified by numerical simulation. Because of the overlapping of pulses, the single-channel analog-to-digital converters can only be used to process discrete time signals, but parallel multi-channel processing is needed to process the time-continuous signals. Therefore, from the point of view of device usage, parallel multi-channel time-stretched analog-to-digital conversion technology is equivalent to using multiple electronic analog-to-digital converters with low sampling rate to construct a high sampling rate analog-to-digital conversion system. Through the system design, the function of this kind of A / D converter is realized experimentally. First, a 10 times time stretching system with a single channel is designed, and the output results of the envelope are obtained. Furthermore, a parallel multichannel 4 times time stretching system is designed, and the system is constructed, and a seamless optical carrier is obtained, which can process the time continuous signal. The time stretch signal output of each channel is obtained and analyzed accordingly.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN792

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