METHOD AND APPARATUS FOR DETERMINING CORRELATION IN FREQUENCY OF VIBRATION WITH SOUND RADIATED FROM THIS VIBRATION

摘要

PURPOSE:To discriminate a frequency of vibration wherefrom a radiation sound is generated and to enable appropriate suppression of vibration of the frequency for making noise low, by superposing a matrix diagram of a frequency response function and a spectral diagram of the radiation sound from a point of excitation. CONSTITUTION:All measuring points 17 are excited as points of excitation sequentially by an impulse hammer 1, and a force F of excitation and an output A of an acceleration level detected by an accelerometer 3 are inputted to a fast Fourier transform device 5. The device 5 executes a signal processing in a frequency region by Fourier transform and determines a frequency response function H of the points of excitation by the hammer 1 by a formula I, H = A/F. Next, the position of fitting of the accelerometer 3 at the measuring points 17 is altered and the frequency response functions H at all the points of excitation are determined by the formula I. Subsequently, the determined frequency response functions H at all the points of excitation are added up and a frequency response matrix diagram of a frame 15 as a whole is determined. By this method, the correlation in the frequency of vibration with a sound radiated from the vibration is determined easily and appropriate suppression of the vibration of the frequency for making noise low is enabled.