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 the safety. With the continuous improvement of train speed in our country, the railway transport capacity increase year by year, the railway in our country is becoming more and more important role in the lives of the national economy. In order to secure safety and smoothness of railway transport, how accurate, rapid detection of track circuit frequency shift signal has become an important subject.
At present, there are many formats of track circuit in the electrified section in China, such as 25Hz AC counting signal, 75Hz AC counting signal, frequency-shift keying track circuits. As the track circuit of 25Hz AC counting signal and ZPW-2000A non-insulated frequency-shift keying track circuit is used widely in electrified section, this paper take them as example. As there are various sources of interference in the field environment, this paper firstly analyze these two signals both in time domain and frequency domain, secondly use the theory of wavelets transformation theory to de-noise the noise-signal, finally analyze the signal of 25Hz AC counting signal and frequency-shift keying track circuits. From the simulation results can be seen that the wavelet analysis of signal detection AC counting error is small, strong anti-jamming capability, using the method to overcome the shortcomings of traditional methods 0,1 threshold is difficult to select, and get below the frequency of using wavelet the analysis has important practical significance and practical value of these two signal detection methods to improve the accuracy of the railway signal detection.
Key words: Track circuit, Wavelets transform, AC counting signal, De-noise, Signal detecting
目 录
1 绪论 1
1.1 铁路信号系统发展概况 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 轨道电路移频信号的建模 3
2.1 轨道电路 3
2.1.1 轨道电路工作原理 3
2.1.2 轨道电路作用和技术要求 4
2.2 轨道移频信号 4
2.2.1 25Hz交流计数信号的时域分析 4