Automated Window Selection and Frequency-Band Weighting for Reliable Magnetotelluric and Audio-Magnetotelluric Impedance Estimation

Low-frequency electromagnetic sounding, particularly magnetotellurics (MT) and audio-magnetotellurics (AMT), is widely applied to characterize subsurface resistivity. In operational settings, however, impedance estimation is frequently constrained by cultural noise, power-line harmonics, grounding artifacts, and instrument drift, which can substantially degrade data reliability. Under such conditions, automated selection of usable time windows and principled weighting of frequency bands become critical determinants of estimation stability. This literature review examines methodological approaches to window selection and frequency-band weighting in MT/AMT processing, focusing on coherence- and stability-based quality metrics and decision rules that span hard rejection and soft weighting. The review also discusses how these quality control procedures interact with transfer-function estimation workflows and reporting practices. Emphasis is placed on reproducibility and the transparent specification of quality control criteria, while summarizing commonly reported applicability conditions, limitations, and failure modes in the existing literature.