| 摘要 |
PROBLEM TO BE SOLVED: To provide a means for reducing acceleration increasing even when a drive signal is reduced to the vicinity of zero because resonance energy of a specimen 10 is large. SOLUTION: In a vibration test machine provided with an excitation table 20 to which a specimen 10 is attached, a vibration exciter 30 which is a vibration generation source, an accelerometer 40 detecting acceleration applied on the a specimen 10, a charge amplifier 50 amplifying a signal from the accelerometer 40, a control part 60 generating the drive signal 103 controlling acceleration applied on the specimen 10 to a specified excitation level for the specimen 10 based on signals from the charge amplifier 50, and an electric power amplifier 70 amplifying the drive signal 103 to a large power for exciting the specimen 10, a switch 81 turning the signal from the charge amplifier 50 on or off and a phase inversion circuit 82 supplying a phase inversion signal 105 inverting a phase of the signal from the charge amplifier 50 turned on by the switch 81 to the control part 60 are provided therein.
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