关键词: 重力仪, 电磁反馈, 开环(闭环)线路, 地震预报

Abstract: GS-15 gravity meter gains a high accuracy in the light of measuring relative change of gravitation through shifting swing bar; the capicity tranducer is used here in measuring the shift.Conventional gravity meter tends to loss the high-frequency component of 0.01 H2 and shows the destorted signals with an open loop in use as well as with a source related filter added to the last stage of the system it; follows that the measuring accuracy can not be improved due to a nonlinear circuit.The author has made a component of feedback circuit for the meter in question and taken a closed loop other than the former one; variation of gravitation is represented by the output of the feedback circuit;the electromagnitic force keeps the swing bar in a entire dynamic process of being balanced with an electric level of zero and thus the capicity balanced bridge of the closed-loop system takes the place of the former one, with a time constant of 2 sec..The improved circuit takes off the nonlinear effect and the recorded solid tide may show its extensive harmonic waves and an additional stable output of zero level which may give various data for the study of crustal defomation. seismic prediction and geophysics.

Key words: Gravity meter, Electromagntic feedback, Open(Closed) loop, Seismic prediction