Three Dimensional Expression of the Tympanogram at Continuous Change of the Probe Tone Frequency

The data of frequency characteristic in the external ear canal were stored in a microcomputer when the frequency of the probe tone was changed continuously at conditions of varying grade of air pressure. Then, the three dimensional (probe tone frequency, air pressure and sound pressure) expression of the tympanogram was obtained. The device can estimate acoustic impedance according to the continuous change in frequency of the probe tone, and this is one of the better methods than the tympanogram used only 220Hz probe tone.