Directional hearing aid
US4751738A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1984 |
| Grant date | Jun 14, 1988 |
| Priority date | — |
| Expiry date | Nov 29, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2225/43
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A pair of sensitive microphones or transducers are mounted on a user's body, spaced apart by a distance equal to one-half a wavelength of the center frequency of a range of frequencies to be emphasized. By summing the outputs of the two microphones, sound in the broadside or look direction (i.e., the direction the listener faces, the microphones being on a line perpendicular to this direction) are emphasized; sounds in the endfire or side directions are nulled or produce a substantially null response in the region of the center frequency defined by the microphone spacing. A third microphone may be added that is not equally spaced from the microphones on either side, but is spaced to provide half wavelength distances which define maximum and null responses centered at the other points within the frequency range (1-4 KHz) desirable for highly effective hearing. The summed signal from each mircophone pair is bandpass filtered. Three bandpass filters are used. The centers of their pass bands are 1200 Hz, 2250 Hz, and 3600 Hz, respectively. Thus each microphone pair and associated bandpass filter is responsible for providing a directonal receiving capability in its assigned range of fre…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.