摘要：城市轨道交通的行车密度大、间隔短、速度快，轨道电路移频信号对保障行车安全发挥了重要的作用。随着我国列车速度的不断提高，为了确保铁路运输的安全畅通，铁路系统对列车自动控制的要求越来越高，轨道电路的使用负荷也不断增大。如何精确、快速的检测轨道电路移频信号成为一个重要课题。
本文从轨道电路移频信号入手，以电气化区段轨道电路中较为常用的25Hz交流计数信号和ZPW-2000A无绝缘移频轨道电路信号为例，对这两种信号进行分析研究。对这两种信号进行时域和频域上的分析，并分析干扰信号的噪声来源，利用小波分析方法对25Hz交流计数信号和ZPW-2000A无绝缘移频轨道信号进行降噪处理和检测。20344
根据小波变换理论分别对 25Hz交流计数信号的理想信号和含噪信号分别进行检测。分别使用了小波降噪和小波包降噪两种不同的方法对移频轨道信号的降噪部分，给出仿真结果。
关键字： 轨道电路；小波变换 ；降噪
Track circuit frequency shift signal detection and processing
Abstract：Traffic density of city rail traffic, interval is short, fast, play an important role in frequency shift track circuit to ensure traffic safety. With the continuous improvement of train speed, in order to ensure the safety of railway traffic, more requirements for automatic control of train rail system is high, the use of load increasing of track circuit. How accurate, rapid detection of track circuit frequency shift signal has become an important subject.
This article from the track circuit of frequency shift signal, non insulated track circuit of frequency shift signal as an example in the electrified section track circuit is commonly used in the 25Hz ac counting signal and ZPW-2000A, to analyze the two signal. Analysis of time domain and frequency domain of the two signal, and the analysis of noise sources of interference signal, no insulation denoising and detection of frequency shift track signal on 25Hz ac counting signal using ZPW-2000A and wavelet analysis method.
Detection was based on the theory of wavelet transform are ideal signal to 25Hz ac counting signal and noise signal. Use of wavelet and wavelet packet denoising of two different methods for noise reduction of the frequency shift track signal, simulation results are given.
Key words: Track circuit;wavelet transform; noise reduction
目 录
1 绪论 1
1.1 课题的研究背景 1
1.2 轨道电路的介绍 1
1.3 轨道移频信号检测技术的现状 2
2 轨道电路移频信号检测方法 4
2.1 轨道电路移频信号的介绍 4
2.2 轨道电路移频信号的特点 4
2.3 轨道移频信号的相关检测方法 5
2.2.1 限幅鉴频法 5
2.2.2 过零周期检测法 6
2.2.3 测宽法 7
2.4 轨道移频信号干扰分析 7
3 小波变换和小波包理论 8
3.1 小波变换理论 8
3.1.1 小波变换 9
3.1.2 二进制小波变换 9
3.1.3 离散小波变换 10
3.2 小波变换用于通信信号消噪的原理和过程 10
3.3 小波包分析 11
4 小波变换对轨道信号降噪处理中的应用 13
4.1 小波降噪理论 13
4.2 小波包消噪的原理 13
4.3 阈值消噪原理 15
4.3.1 用阈值消噪 15
4.3.2 阈值的设置 16
5 小波变换对轨道信号降噪处理中的仿真 17 轨道电路移频信号检测与处理+仿真程序:http://www.751com.cn/tongxin/lunwen_12088.html