Abstract: Under hearing conditions, the amplitude of the motionof the human tympanic membrane is in the range ofseveral tens of nanometers. To measure motions of thissize by a touchfree method is a domain of lasertechnology. Here laser-Doppler-vibrometry was chosenbecause of its sensitivity in detecting smallamplitudes and the clear information about the detectedpoint on the tympanic membrane. Care was taken todevelop the method for a clinically acceptableprocedure for hearing diagnosis. The first realizationby sinus wave excitation was found to be very timeconsuming. A measuring time of less than a minute wasobtained by white noise excitation, fast Fouriertransformation and choosing the umbo as the detectionpoint. Meanwhile the setup is used for in vivomeasurements. !14
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