In the process of signal transmission, noisy signals interfere with normal signals unavoidably.
Wavelet soft-threshold de-noising method was applied to preprocess the noisy signal, and the noise interference in disturbance detection was reduced to a great extent.
On the basis, the characteristics called the ICA Energy (ICAE) and the Filtered ICAE (FICAE) are used for the noisy signal endpoint detection.
In practice, the signal derived in this way would be useless, since each differentiation exaggerates any errors present, and so a double differentiation would inevitably produce a very noisy signal.
