Michael W Steele

US Patent:

6397037, May 28, 2002

Filed:

Dec 10, 1999

Appl. No.:

09/424915

Inventors:

David Franklin - Somerville MA
Michael Steele - Seaford NY

Assignee:

Audiological Engineering Corporation - Somerville MA

International Classification:

H04H 100

US Classification:

455 301, 455 306, 455575

Abstract:

An RF-type amplification system, such as a classroom amplification system, employs technology adapted from a cordless telephone system to overcome interference. The amplification system includes a portable remote unit ( ) and a base unit ( ). Remote unit ( ) includes: a microphone ( ) for detecting a voice and generating corresponding voice signals; a transmitter ( ) which generates RF signals containing the voice signals as well as control signals provided by the central processing unit ( ) of remote unit ( ), and an antenna ( ) for transmitting the RF signals and for receiving RF signals from base unit ( ). Base unit ( ) includes an antenna ( ) which receives the RF signals transmitted by the remote unit and a receiver ( ) which detects the RF signals and separates the RF signals into the voice signals and control signals. The control signals are identified by a code detector ( ) of base unit ( ) and evaluated by a CPU ( ). If the values of the control signals are as expected, the voice signals are processed through a speech network ( ) and provided at a communications interface to an audio power amplifier ( ) which amplifies the voice signals and supplies the voice signals to speakers which audibly project the voice signals as sound.

US Patent:

57941874, Aug 11, 1998

Filed:

Jul 16, 1996

Appl. No.:

8/687014

Inventors:

David Franklin - Somerville MA
Michael Steele - Seaford NY

Assignee:

Audiological Engineering Corporation - Somerville MA

International Classification:

G10L 302

US Classification:

704225

Abstract:

Improved signal to noise ratio to help speech comprehension in a noisy environment is accomplished by selectively downwardly expanding a speech and noise composite signal when the speech signal is absent, thereby lowering signal components which represent noise. An expansion control signal is extracted from the composite input signal. Operation is based on the assumption that when noise alone is present, the input signal amplitude is less than some reference level and that when speech and noise are present together, the input signal amplitude is greater than the reference level. The response rates of gain changes are quite rapid, and do not introduce distortion or other audibly noticeable artifacts of the processing. The amount of downward expansion of the noise alone is small compared to noise gates to further reduce processing artifacts. The methods of realization include use of, in combination and alone, analog compressors and expanders, analog expanders in combination with voltage clamps and/or automatic level control circuits, two-quadrant multipliers in conjunction with digital control, entirely digital means for obtaining the requisite sensing and gain control, and expandor designs that are analogs of conventional filter designs where the notion of amplitude replaces frequency.