An overview of the giant magnetoimpedance phenomenon is given in this work. The effect, that consists of drastic changes of the complex impedance of soft magnetic materials upon the application of an external magnetic field, has attracted attention owing to the increasing perspectives of applications on magnetic and stress sensor technology. In particular, asymmetric response is specially indicated for specific applications, and many experimental and theoretical results have been developed so far. A novel approach to investigate the GMI, based on the Fourier analysis of the time derivative of magnetization, will be discussed in further detail.