Output frequency correction method, tsunami warning device, and tsunami warning system

摘要

PROBLEM TO BE SOLVED: To provide an output frequency correction method for a pressure sensor for measuring the number of rectangular waves defined as a fixed value in the prior arts and correcting influences of missing in counting of the rectangular waves, and to provide a tsunami alarm apparatus and a tsunami alarm system for simultaneously measuring an earthquake motion and an air pressure while using the output frequency correction method, and discriminating a degree of danger of tsunami attack from the measurements.SOLUTION: The present invention relates to an output frequency correction method for a pressure sensor, which corrects influences of missing of counting of rectangular waves outputted from the pressure sensor. The output frequency correction method is characterized in that, each time a piece of time width data T[i] of a frequency-divided rectangular wave is obtained, a frequency dividing ratio is estimated and a time width Tper rectangular wave is calculated in accordance with T=T[i]/Nand N=rint(T[i]/T), where (i) is the number of time-series steps, Nis an estimated frequency dividing ratio, rint() is a function returning a closest integer, and Tis a representative value of a time width per rectangular wave.SELECTED DRAWING: Figure 5