Electrical audio signal processing systems and devices – Hearing protectors – electrical
Patent
1994-02-22
1994-10-11
Kuntz, Curtis
Electrical audio signal processing systems and devices
Hearing protectors, electrical
381 94, 381 682, 381 684, A61F 1106
Patent
active
053554183
ABSTRACT:
A frequency selective hearing protection device and method utilizes adaptive filtering to hinder transmission of frequency components in ambient sound above a preselected threshold level. Sound frequency components which are not above the threshold level, such as normal speech, are allowed to pass. Electrical analog signals produced by a transducer are converted to a stream of digital input signals. The digital input signals are applied to a digital filter such as an FIR filter implementing a time domain difference equation. As a result, digital output signals are produced which are reconverted to analog output signals and applied to an actuator to produce audible sound. To adjust the frequency response of the invention to suppress gain at frequency components above the threshold, windows of input and output data signals are first assembled. Respective frequency domain transforms such as fast Fourier transforms provide spectrums representative of frequency component amplitudes. Any violator components exceeding the threshold level are distinguished and coefficient values of the difference equation are altered to suppress gain at those frequencies. Preferably, the coefficient values are readjusted to again allow the frequencies to pass if the threshold is not exceeded in preselected number of subsequent digital input signals.
REFERENCES:
patent: 4187410 (1980-02-01), Eroshkin et al.
patent: 4187413 (1980-02-01), Moser
patent: 4658426 (1987-04-01), Chabries et al.
patent: 4868880 (1989-09-01), Bennett, Jr.
patent: 5027410 (1991-06-01), Williamson et al.
patent: 5027412 (1991-06-01), Hayashi et al.
patent: 5029217 (1991-07-01), Chabries et al.
Numerical Recipes: The Art of Scientific Computing (FORTRAN Version), Press, Flannery, Teukolsky & Vetterling 386-429 (1989).
Aschliman Larry D.
Kelsey Randy J.
Kelly Mark D.
Kuntz Curtis
Westinghouse Electric Corporation
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