Directional microphone system
US4653102A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 5, 1985 |
| Grant date | Mar 24, 1987 |
| Priority date | — |
| Expiry date | Nov 5, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/005
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to an improved directional microphone system which utilizes at least two directional microphones. The microphones included in the system are connected to an electrical circuit which is programmed to cancel static noise and to facilitate dynamic gain control. The received signals from the two microphones are fed into a microcomputer where a fast Fourier transformation is made on the two signals in order to go from the time domain to the frequency domain. A lowpass and highpass filtering technique is used to cancel the dynamic noise. The frequency components of the incoming signals are further used to utilize an area and phase sorting technique to allow only the pickup of the wanted sound in a well-defined area. An inverse fast Fourier transformation is made and the modified signal is outputted in the time domain. Sounds generated from outside the work area are essentially cancelled out by a combination of the directionality of the microphones and the sorting techniques employed. The sorting techniques actually measure extraneous noises within the work area and compensate for them so as to enhance the signal-to-noise ratio for sounds generated within the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.