自动控制文献翻译——摘要：

移频键控(频移键控)信号，它具有带宽窄，抗干扰能力强，传输距离长等优点，用于无绝缘移频轨道电路中来发送不同的控制信号。然而，由于移频键控是非线性调制，所以高精度参数估计是很难实现的。基于时频分布的频谱分析的补充，提出了高精度移频键控信号参数估计算法。 根据信号特征,使用欠采样和ZFFT来提高频谱分析的准确性,并且基频率分辨率达到0.02Hz的系统要求。维纳分布具有优良的时频聚集性即使同时有严重的交叉项干扰。通过核函数的设计，抑制了交叉项干扰抑制并且上/下频率分辨率满足Lee系统需求0.2Hz。上面所提到的方法的有效性都由MATLAB仿真证明，为高精度移频键控信号参数估计设备的发展做了坚实的铺垫。

1 引言

如今，没有轨道电路的控制，非电气化铁路或高速铁路也可以运行。为了保证电气化和高速铁路的运输安全，在近二十年它经历了一个飞速发展的过程，比起普通铁路，先进的技术和高性能设备中越来越需要轨道电路的高精确度估计。

在本文中，重点研究了对无绝缘移频轨道电路的高精度参数估计方法。移频键控信号，它具有带宽窄，抗干扰能力强，传输距离长等优点，用于无缝移频轨道电路中来发送不同的控制信号。由于不同的参数的频移键控信号表明不同的控制信息，为了准确的提取响应的信息、满足系统的要求，基频参数估计的分辨率和上/下边频需要分别达到0.02Hz和0.2Hz。针对这一问题，大量的估计方法过早地提了出来，可大致分为两类：时域滤波和计数方法，和基于傅里叶变换的频谱分析方法。与时域方法相比较，光谱的抗干扰分析的方法有了很大的提高。然而，由于它适用于在整个时间域的全局变换，谱分析法只能估算反射的平均特性参数，例如基频，但是对于上、下边频的估算它是无效的。在二分之一边频信息调制周期内已经通过设置窗函数，但是这个方法的估计精度大幅下降，甚至当一个额外的数据添加的。时频分布是针对这个问题的一种有效的解决方法，它同时提供了在时域和频域中的信号信息，因此克服了单独的时域或频域分析的缺点。基于FSK信号特性的研究，频谱分析和时频分布，提出了一种高精度的FSK信号估计算法。本文的组织如下：第2部分的分析FSK信号的特点；第3部分分别提出了具体的基频和上下边频的参数估计方法；第四部分对它的性能在进行评估；第5部分是结论。

2 信号分析

无绝缘移频轨道电路中信号的传输是一致的，二进制移频键控信号，上行方向的载波频率f0在2000Hz和2600Hz之间交替出现，而下行方向的载频为1700Hz和2300Hz。该载波频率f0的补偿频率 Δf是11Hz。调制基频f1从10.3Hz开始到29Hz，频差是1.1Hz。

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Abstract:

FSK (Frequency Shift keying) signal, which has advantages of narrow-bandwidth, strong anti-interference ability, long transmission distance and so on, is used in jointless Frequency-shift track circuit to send different kinds of control signals. However, as FSK is non-linearly modulated, parameter estimation with high accuracy is hard to realize. Based on the spectrum analysis complement with time-frequency distribution, a high-accuracy FSK signal parameter estimation algorithm is put forward in this paper. According to the signal characteristics, under-sampling and ZFFT are used to improve the accuracy of spectrum analysis, and the base frequency resolution meets system requirement of 0.02Hz. Wigner-Ville distribution has an excellent time-frequency concentration while serious cross-term interference at the same time. Through the design of kernel function, the cross-terms are almost suppressed and the upper/down side frequency resolution meets the system requirement of 0.2Hz. The effectivities of all the methods mentioned above have been proved by MATLAB simulation, which pave a solid way for the development of high-accuracy FSK signal parameter estimation devices. 

1 Introduction 

Nowadays, no electrified or high speed railways can work without the control of track circuit. In order to guarantee the transport safety of electrified and high speed railways, which experiences a flying development in recent two decades, advanced techniques and high performance devices are more and more needed in the high-accuracy estimation of their track circuit than that of the ordinary railway. 

In this paper, we focus on discussing high-accuracy estimation methods for jointless frequency-shift track circuit. FSK signal, which has advantages of narrow-bandwidth, stronganti-interference ability, long transmission distance and so on, is used in jointless Frequency-shift track circuit to send different kinds of control signals. Since different parameters of FSK signals indicate different control information, in order to extract the corresponding information accurately and fulfill the system requirements, the parameter estimation resolution of base frequencies and upper/down side frequencies should be up to 0.02Hz and 0.2Hz, respectively. Aiming at this issue, a lot of estimation ......