| The tympanometry on ear system is a new developmental impersonal method to examine thefunction of middle ear in recent years. It has obtained clinician's recognition, and has an importantstatus in the clinical otology and the audiology diagnosis. What is more, it has become anadvanced method to enhance the diagnose accuracy of the ear illness. At present, tympanometryhas been used in clinic generally, in which most of the measurements are confined to lowfrequency and single ingredient. So it is mainly used to distinguish middle ear illness according tothe changes of acoustic stiffness sonar mostly, However, the effect to distinguish middle ear lesiondue to the changes of mass sonar is not obvious.This paper which researched on a multi-frequency tymmpanometry on ear system was basedon arm. The effects to distinguish middle ear lesion according to the changes of either acousticstiffness sonar or mass sonar are all very good.The multi-frequency tymmpanometry circuit was designed in this systerm. Direct DigitalSynthesizer (DDS)which was designed by FPGA can transmit multiple frequency probing tone.Low-frequency probing tone mainly used to distinguish middle ear illness according to thechanges of acoustic stiffness sonar mostly, while high-frequency probing tone is sensitive to thechanges of mass sonar mostly. To discuss the phase angle relation of variation rule in process ofmeasuring acoustic conductance of different ears and ear lesion, this paper designed the detectingcircuit of phase angle tympanogram. Furthermore, this paper has carried on the measurement andresearch on phase angle tympanogram between regular ear and conductivity lesion ear.To discuss the phase angle relation of variation rule in process of measuring acousticconductance of different ears and ear lesion, this paper designed the detecting circuit of phaseangle tympanogram. Furthermore, this paper has carried on the measurement and research onphase angle tympanogram between regular ear and conductivity lesion ear. |
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