Curtis J Reed

US Patent:

7203324, Apr 10, 2007

Filed:

Mar 13, 2003

Appl. No.:

10/387915

Inventors:

Richard A. Kreifeldt - Sandy UT, US
Curtis R. Reed - Salt Lake City UT, US
Aaron M. Hammond - Eagle Mountain UT, US

Assignee:

Harman International Industries, Incorporated - Northridge CA

International Classification:

H04B 15/00
H04R 27/00

US Classification:

381 93, 381 83, 381 96

Abstract:

This invention is an audio system capable of identifying frequencies of feedback signals and filters these feedback signals. Frequency interpolation is utilized on a sampled frequency spectrum signal corresponding to a feedback signal, where the frequency interpolation allows the frequency of the feedback signal to be identified, especially where the frequency lies between samples of the frequency spectrum signal. The frequency identification allows a less intrusive filter, such as a notch filter, to be placed at the determined frequency of the feedback to eliminate the feedback signal. The placement of the notch filter reduces the effect on the audio signal provided by the audio system. The audio system may provide adaptive filtering of multiple feedback signals, using a single filter such as a notch filter. The single notch filter is configured to filter the more than one feedback signal, thereby freeing-up notch filters for filtering other feedback signals, or for reducing memory and processing requirements for the processor of the system.

US Patent:

7602925, Oct 13, 2009

Filed:

Oct 31, 2005

Appl. No.:

11/264628

Inventors:

Richard A. Kreifeldt - Sandy UT, US
Curtis R. Reed - Salt Lake City UT, US
Aaron M. Hammond - Eagle Mountain UT, US

Assignee:

Harman International Industries, Incorporated - Northridge CA

International Classification:

H04B 15/00
H04R 27/00

US Classification:

381 93, 381 83, 381 96

Abstract:

A signal processing system improves signal quality by accurately locating and eliminating a feedback signal in an input signal, such as an audio signal. The signal processing system interpolates between frequency sample points to obtain a more accurate identification of a feedback signal frequency. A less intrusive filter reduces or eliminates the identified frequency signal frequency without excessive adverse effects on adjacent frequencies in the input signal.

US Patent:

8054993, Nov 8, 2011

Filed:

May 26, 2004

Appl. No.:

10/853828

Inventors:

Richard Allen Kreifeldt - Sandy UT, US
Timothy Shuttleworth - Woodland Hills CA, US
Curtis Rex Reed - Salt Lake City UT, US

Assignee:

Harman International Industries, Incorporated - Northridge CA

International Classification:

H03G 5/00
H04R 29/00

US Classification:

381101, 381 56, 381 98, 381103

Abstract:

A system for boosting the bass of an audio signal to closely match or mirrors a plurality of Robinson-Dadson loudness curves by interpolating coefficients from a table of values representing the Robinson-Dadson loudness. The system having a controller that interpolates the coefficients from the loudness curves and then uses the coefficients in a shelf filter that makes adjustments to the audio signal. The result of the adjustments to the audio signal is the introduction of bass boost slowly through a diminuendo or lowering of level through volume adjustment and to removes the bass boost rapidly during a crescendo or increase in level through user volume adjustment.