Directional microphone
US5848172A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1996 |
| Grant date | Dec 8, 1998 |
| Priority date | — |
| Expiry date | Nov 22, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2201/403
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A monolithic second order gradient (SOG) microphone structure employs acoustic transmission lines wherein the acoustic phase delay along each of the acoustic transmission lines is in direct proportion to the length of each of the acoustic transmission lines and, where this is effected by the use of an acoustic impedance element placed within each acoustic transmission line that has an acoustic impedance related to the acoustic impedance of the associated acoustic transmission line. In one embodiment, the acoustic impedance element has a specific acoustic impedance substantially matched to the specific acoustic characteristic resistance of the acoustic transmission line. Various embodiments may utilize acoustic or electrical subtraction of the signals in the acoustic transmission lines to realize the desired directional sound pickup.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.