Acoustic admittance measuring apparatus with wide dynamic range and logarithmic output
US4966160A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 1986 |
| Grant date | Oct 30, 1990 |
| Priority date | — |
| Expiry date | Oct 2, 2006 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/121
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An electrical circuit system for measuring the acoustic admittance of the ear cavity, for use in single and multiple tone tympanometry and acoustic reflex response testing, in which the probe tone applied to the ear cavity can be varied over a wide frequency range and a wide range of admittance variation can be measured. The signal output of the system, derived from the output signal of a microphone located in the ear cavity, is a DC voltage accurately proportional to the logarithm of the measured admittance of the ear cavity. An RMS to DC converter, an error integrator and an exponential element provide a closed control loop system for a variable gain amplifier so as to maintain the microphone output signal level constant regardless of admittance variations in the ear cavity. The level of the signal applied to the probe tone driver to accomplish this is a measure of the cavity admittance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.