NLMS算法在轨道电路信号解调中的应用

The Application of NLMS Algorithm in the Track Circuit Signal Demodulation

针对目前轨道电路FSK信号解调中传统解调方法解调精度不足的问题,在对自适应滤波理论研究的基础上,提出采用基于NLMS算法的自适应滤波模块,利用传统频谱分析法得出轨道电路FSK信号的载频信息作为自适应滤波模块的期望信号,通过提取其中一个载频分量从而还原调制方波,经过计算后得出调制频率,实现信号的解调。仿真结果证明NLMS算法不仅实现了轨道电路FSK信号高精度的解调,并且解决了传统LMS算法在轨道电路FSK信号解调中收敛速度慢的缺陷,具有良好的抗噪性能。

On the basis of the research on adaptive filter theory, a new adaptive filtering module based on NLMS algorithm has been proposed to improve the demodulation accuracy of traditional demodulation in the current track circuit FSK signal demodulation. This new adaptive filtering module first uses conventional spectrum analysis method to get the carrier frequency information of the track circuit FSK signal as a desired signal adaptive filter module, then restores the square wave modulation by extracting one of the carrier frequency component, and final- ly, demodulates the signals through calculating the modulation frequency. The simulation results show that NLMS algorithm not only achieved high precision demodulation of track circuit FSK signal, but also solved the slow con- vergence defects of traditional LMS algorithm in the track circuit FSK signal demodulation, and has good anti-noise performance as well as.