1. Zhou, Z., Wen, Z., Pu, Y.: Application study of wavelet analysis on ultrasonic echo wave noise reduction. Chin. J. Sci. Instrum. 30(2), 237–241 (2009)
2. Luo, X., Chen, T., Wan, Y.: Wavelet packet analysis to signal in ultrasonic testing. Chin. J. Mech. Eng. 42(4), 142–146 (2006)
3. Lu, C., Wu, G., Wu, W.: Application of wavelet transform to the testing echo processing of ultrasonic flaw detector. Chin. J. Sci. Instrum. 24(6), 559–563 (2003)
4. Zhang, H., Zhou, Q., Xia, J.: Wavelet packet denoising and feature extraction for flaw echo signal in ultrasonic testing. Chin. J. Sci. Instrum. 27(1), 94–97 (2006)
5. Shim, I., Soraghan, J.J., Siew, W.H.: A noise reduction technique for on-line detection and location of partial discharges in high voltage cable networks. Meas. Sci. Technol. 11(12), 1708 (2000)