Localization of computer acoustic signal source

Plenty of devices emanate acoustic signal, which is not necessarily located in the hearing range. Attacks on this side channel develop, from distinguishing sounds of mechanical key pressing on the keyboard up to processor's instruction recognition. In the case of complex analysis of electronic components emanation, the daunting challenge is to locate the precise source of the sound. Sound emanation can be the result of changes in power of power supply circuit. This paper studies behavior of inductors and capacitors within the LC-circuit of voltage regulator and corresponding changes in power consumption in relation to executing instructions.