Abstract
In recent years, a problem of interfering by artificial noises from a electrical power transfer become large and deterioration of a sound quality of an AM radio is worried. In this paper, a noise suppression system using quadrature demodulation techniques is proposed to reduce the effect of the interfering. The proposed system utilizes a fact that the quadrature signal includes only the interference, while the in-phase signal from the demodulator includes both of AM signal and interference. To cancel the noise component in the in-phase signal, the noise component in the quadrature signal is adjusted by a tapped delay line because the sign of the both interference is different each other. Weight coefficients of the tapped delay line are determined based on power inversion (PI) algorithm. Thus, the interference in the in-phase signal can be canceled by the quadrature signal. Validity of the proposed system is shown through computer simulations.
