Wavelet analysis of measurements for on-line testing analog & mixed-signal circuits

In this paper a test method based on the wavelet transformation of the measured signal, be it supply current (I_PS) or output voltage (V_OUT) waveform, is presented. In the wavelet analysis, a test metric named discrimination factor is introduced utilizing information from initial two decomposition levels of the measured signal. The tolerance limit for the good circuit is set by statistical processing data obtained from the fault-free circuit. Experimental comparative results between the proposed method, a test method based on the RMS value of the measured signal, a test method utilizing the harmonic magnitude components of the measured signal spectrum and a method based on the wavelet transformation of the measured signal are presented showing the effectiveness of the proposed testing scheme.