Keith Cory Davis

US Patent:

6717537, Apr 6, 2004

Filed:

Jun 24, 2002

Appl. No.:

10/179930

Inventors:

Xiaoling Fang - Irvine CA
Keith L. Davis - Salt Lake City UT
Martin R. Johnson - Draper UT

Assignee:

Sonic Innovations, Inc. - Salt Lake City UT

International Classification:

H03M 300

US Classification:

341143, 381 74

Abstract:

A method and an apparatus for minimizing latency in digital signal processing paths. One example is an active noise cancellation device. The system includes a digital closed feedback loop having a forward path and a feedback path. The forward path includes a compensation filter, a digital-to-analog converter, and an output transducer. The feedback path includes an input transducer, a feedback delta-sigma modulator, and a feedback sampling-rate converter. An input signal is processed in one of several ways into a processed digital input signal having a preselected intermediate sampling rate. Through the feedback path, an analog output signal is processed into a digital feedback signal having substantially the same preselected intermediate sampling rate. The processed digital input signal and the digital feedback signal are combined and processed through the forward path to produce an anti disturbance signal that is combined with a disturbance signal to form the analog output signal.

US Patent:

47860600, Nov 22, 1988

Filed:

Sep 16, 1987

Appl. No.:

7/097135

Inventors:

Keith B. Davis - Long Beach CA

Assignee:

McDonnell Douglas Corporation - Long Beach CA

International Classification:

E21B 3300
B05C 902
B23P 2500

US Classification:

277 1

Abstract:

Method and system for applying liquid sealant in holes of a structural member prior to installing fasteners in such holes, which comprises mixing air with a liquid sealant, spraying a controlled amount of the resulting air-sealant mixture into the holes and depositing liquid sealant therein, and impinging an elevated pressure air stream on the deposited liquid sealant to spread the sealant out and produce a thin layer of sealant in the holes. A system for carrying out the method comprises a spray gun having separate air and liquid sealant paths which meet at the spray nozzle of the spray gun to achieve the mixing of air with the liquid sealant. The liquid spray system also includes a sealant applicator controller which is arranged to activate a series of timers and valves to provide controlled flow of high pressure air and liquid sealant to the nozzle for mixture therein, and spraying to form the sealant deposit, and to provide for continued high pressure flow of air on the layer of sealant deposit to spread the sealant and produce a thin sealant layer.