METHOD STUDYING PERIODIC VIBRATIONS Russian patent published in 1997 - IPC

FIELD: equipment measuring vibrations in microelectronics and mechanical engineering. SUBSTANCE: proposed method includes formation of interference pictures, their conversion to electric signals, reference one and one corresponding to examined vibration, taking characteristics of obtained signals and their comparison to judge amplitude of vibration of examined object. Amplitude of vibration of reference object exceeding λ/4, where λ is length of radiation wave of laser is set before formation of interference picture of reference signal. Envelopes of electric signals, reference and examined, are chosen as criterion for evaluation. Then relation of amplitudes of envelopes of signals of examined to reference one is found. In case of excess or equality of relation of amplitude of reference signal to amplitude of examined signal character of vibrations is determined from proposed relation and amplitudes of harmonics of studied vibrations are found by formulae. EFFECT: increased authenticity of method. 3 dwg, 1 tbl