At+t Corp.

Kevin D Willis

Jeffrey Phillip McAteer

Alan Dean Michel

John C Baumhauer, Jr

Christopher T Welsh

The long term average broad band gains of a plurality of individual signal channels, associated with a corresponding plurality of microphone elements, are electronically and dynamically adapted to one another. This is realized by periodically and dynamically processing the signals from the individual microphone elements. More specifically, the processing is such that the long term average broad band gain of the signal channels of the individual microphone elements is dynamically adjusted, an energy estimate of each microphone signal channel is averaged over the long term and the difference in energy between the signal channels is used to readjust the long term average broad band gain of the microphone signal channels to minimize those differences. In one embodiment, the adjustment is realized by obtaining an estimate of the energy of the adjusted signal in each microphone signal channel, obtaining the differences between the energy estimates and averaging the difference over the long term to obtain a gain differential correction factor which is used to readjust the long term broad band gain of at least one of the microphone signal channels to minimize the gain difference between the microphone signal channels. In another embodiment, a long term estimate of the energy in each microphone signal channel is obtained. A ratio of the energy estimates is obtained and used to adjust the long term average broad band gain of at least one of the microphone signal channels to equalize the gain in the microphone signal channels.

Long-time balancing of omni microphones

Full directional pickup coverage is realized by employing a pickup arrangement which provides a plurality of audio polar directivity patterns, i.e., directional beams. These polar directivity patterns are formed in a unique embodiment of the invention by generating a plurality of frequency independent time-delayed versions of a corresponding plurality of spatially sampled signals and by combining each of the plurality of spatially sampled signals with one or more selected ones of the time delayed versions to generate at least a similar plurality of polar directivity patterns. More specifically, the spatially sampled signals are combined with the delayed versions in such a manner that a greater number of polar directivity patterns can be considered than the number of spatially sampled signals. In a specific embodiment, the spatially sampled signals are acoustic (audio) and a plurality of microphones arranged in a predetermined spatial configuration is employed to obtain them.

Directional microphone system

A speakerphone comprises an upper housing member and a lower housing member that are joined together to enclose a loudspeaker, a microphone, and a printed wiring board having electronic components mounted thereon that cooperate in the operation of the speakerphone. The upper housing member includes a continuous sidewall that is molded into its underside and extends downwardly toward the printed wiring board. The sidewall surrounds a group of sound apertures that are also molded into the upper housing member. A loudspeaker is attached to the underside of the upper housing member in such a manner that it completely covers the sound apertures. A sealed enclosure within the speakerphone is formed by creating a seal between the sidewalls and the printed wiring board. A compliant gasket is illustratively used to create the seal. As a result, the frequency response of the loudspeaker is improved, and acoustic coupling between the loudspeaker and the microphone is reduced. The frequency response of the loudspeaker is further improved by inserting acoustically absorbent material, and by extending a tuned port, into the sealed enclosure.

Growing community of inventors

Owensboro, KY, United States of America

Kevin D Willis