Calculation of noise resistance by use of the discrete wavelets transform

Discrete wavelet transform (DWT) was applied to the electrochemical noise a nalysis (ENA). The original potential noise and current noise were first de composed into a series of details D-j and approximation A(j) by DWT at incr easing scale j. Then, the noise resistance R-n(j) was calculated as a ratio of the standard derivation of the reconstructed potential noise to the rec onstructed current noise. The experimental results demonstrated that the DW T could improve the calculation of the classic noise resistance R-n and spe ctrum noise resistance R-sn(f) because it could remove the low frequency tr end coupled in the potential or current fluctuations very well. In addition , the variation of R-n(j) with j may provide an insight into the prevalent corrosion mechanisms. (C) 2001 Elsevier Science B.V. All rights reserved.