Patent ID: 7318337

Claim:
A method for measuring frequency characteristics of a direct current acceleration sensor, comprising: supporting a metal rod with a center axis thereof aligned with a direction of gravity acceleration, impacting one of end surfaces of the metal rod with a projectile to generate and propagate an elastic wave pulse in the metal rod, using a direct current acceleration sensor provided on the other of the end surfaces of the metal rod to detect an acceleration arising when the elastic wave pulse reflects at the other end surface of the metal rod, using a strain gauge provided on a side surface of the metal rod to measure metal rod strain caused by the impact of the projectile against the other end surface of the metal rod, and obtaining a frequency response of the direct current acceleration sensor from a signal from the direct current acceleration sensor and a signal from the strain gauge; wherein one end surface of the metal rod is impacted with the projectile to generate the elastic wave pulse in the metal rod, the method further comprising: taking as an input signal to the direct current acceleration sensor provided on the other end surface of the metal rod dynamic displacement, velocity or acceleration in a direction normal to the other end surface produced when the elastic wave pulse generated by the impact of the projectile reflects at the other end surface, using the direct current acceleration sensor to detect, and the strain gauge provided on the side surface of the metal rod to measure, the input signal having time as a function, carrying out signal processing with respect to an output signal from the direct current acceleration sensor and an output signal from the strain gauge, and using data that has been signal processed as a basis for measuring gain-frequency characteristics, phase-frequency characteristics and peak sensitivity of the direct current acceleration sensor in respect of each of dynamic displacement detection function, velocity detection function and acceleration detection function of the direct current acceleration sensor, wherein the strain gauge provided on the side surface of the metal rod is composed of a plurality of strain gauges provided at different distances from the one end surface of the metal rod.