国产欧美精品一区二区,中文字幕专区在线亚洲,国产精品美女网站在线观看,艾秋果冻传媒2021精品,在线免费一区二区,久久久久久青草大香综合精品,日韩美aaa特级毛片,欧美成人精品午夜免费影视

With the advanced development of Chinese railway, track circuit frequency shift signal detection and decoding technologies have received great attention. However, the actual sampled track circuit frequency-shift signals are inevitably mixed with a great deal of background noise and interference, so it is essential to remove the noise before decoding to improve the accuracy of demodulation. For this reason, a novel denoising method for track circuit frequency-shift signal based on sparse decomposition is proposed. A redundancy dictionary is built up according to the feature of frequency shift signal. Based on the dictionary, noise reduction of frequency-shift signal is conducted via the two-phase matching pursuit algorithm. The experimental results on ZPW-2000 frequency shift signals show that this method can effectively remove noise from low SNR frequency-shift signal to improve the decoding SNR by 10dB, which is far better than the wavelet threshold denoising and the empirical mode decomposition denoising algorithms. Moreover, the two-phase searching technique significantly reduces the computation of matching pursuit, and satisfies the real-time requirement of railway applications.