CONTROL METHOD FOR SWEEP OSCILLATION SOURCE IN GROUND INVESTIGATION

摘要

PURPOSE: To perform measurement of ground at high resolution upto a required depth by preliminarily oscillatins an electromagnetic vibrator with a reference signal in order to determine a transfer function and inverse filter thereof, driving a vibrator with a driving signal obtained based on the product of the reference signal and the inverse filter, thereby applying a vibration wave equivalent to the reference signal. ;CONSTITUTION: An electromagnetic vibrator 1 comprises a vibrator 1a to be excited through a power amplifier 2, and a base plate 1b vibrating relatively thereto and transmitting vibration to the ground. A preamplifier 3 takes in acceleration signals of the vibrator 1a and the base plate 1b and an IO box 4 produces a driving signal for the amplifier 2 based on a reference signal where the driving signal is corrected by the output from the amplifier 3. A controller 5 performs calculation processing and control. The vibrator 1a is driven with the reference signal to produce a vibration waveform which is subjected to Fourier transform in order to determine a transfer function and then an inverse filter is calculated. The inverse filter is multiplied by the reference signal to produce a drive signal for redriving the vibrator 1a which then produces a control signal matching with the reference signal. This constitution allows measurement of ground at high resolution upto a required depth.;COPYRIGHT: (C)1994,JPO&Japio