精密に制御された電磁波を用いた3次元精密構造探査のためのデイジタル信号波形の設計

概要

論文の詳細を見る
In order to determine an electric 3-D (three dimensional) structure and monitor its temporal variation, the controlled source technique using electromagnetic wave with multiple frequencies is useful. When the amplitudes and the phases of the electromagnetic waves are accurately controlled, we can measure the transfer function of transmitted and received waves. In order to decrease errors in measurements and analysis, the SNR (signal to noise ratio) should be high and be constant. Digital signals can easily control the SNR, because they have the following merits: the signal can be designed to have 1) narrow frequency band, 2) sharp cut-off frequency, 3) amplitude of frequency response determined from amplitudes of the transfer function and background noise, and 4) phase of frequency response requested for. In actual measurements, the transfer function is first measured using preliminary determined transmitted signal after measuring background noise. Next, the signal is designed using measured transfer function and noise, and the transfer function with a better SNR is obtained.
東京大学の論文