This book is one part of ongoing research project of Ericsson AB together with Blekinge institute of technology on the aspect of Ericsson Power modules. The aim of this project is to apply signal processing method on the measured current signal of inductor component of Ericsson BMR 450 Buck converter by using software Matlab, the method should be able to remove the noisy part which exists on the measured signal, so the signal can be undulated within normal range. A set of solutions have presented in this report. The solutions include the Analog and discrete filter design, the algorithm of reconstruct signal, method of finding the signal slopes and algorithm of finding current average values of signal, also presented in the last chapter of report. The result of this book project provides possible valuable reference for other research part of Power modules and helps the future development technology of DC/DC converter.