| 摘要 |
PROBLEM TO BE SOLVED: To provide a seismometer for fully securing seismic calculated intensity. SOLUTION: An operational amplifier 4 amplifies a detection signal Sa from an earthquake sensor 3 on the basis of a reference voltage Vk from a microcomputer 5, and outputs the amplification signal Sb to the microcomputer 5. An A/D conversion circuit 8 A/D-converts the detection signal Sa and the amplification signal Sb, and outputs 1-fold A/D value and 16-fold A/D value of the digital waveform to a seismic intensity arithmetic circuit 9. The seismic intensity arithmetic circuit 9 gives 4-bit dummy data to the upper level of the 16-fold A/D value and gives 4-bit dummy data to the lower level of 1-fold A/D value for converting to an A/D value for computing respective 14 bits. The seismic intensity arithmetic circuit 9 calculates the current value and average value of the seismic intensity at that point, based on the A/D value for computation, and calculates the difference as a seismic intensity value. At this time, the seismic intensity arithmetic circuit 9 monitors the difference between the 16-fold A/D average value and the reference voltage Vk, and corrects the reference voltage Vk so that the reference voltage Vk approaches the offset voltage of the earthquake sensor 3, when the difference exceeds a prescribed value. COPYRIGHT: (C)2005,JPO&NCIPI |
