Patents by Inventor David C. Tigwell
David C. Tigwell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20120286806Abstract: A substrate is electromagnetically coupled into an inductance-capacitance resonant circuit formed from (i) a member comprising a ferromagnetic material, (ii) an inductor and (iii) the substrate. The substrate is illuminated for a first time period X to cause photoconduction in the substrate. Decay in conductivity of the substrate is monitored for a second time period Y. The ratio of X to Y is greater than 1:10. Bulk lifetime of the substrate is determined from the decay.Type: ApplicationFiled: November 9, 2011Publication date: November 15, 2012Inventors: Francisco Machuca, Ronald Chiarello, G. Lorimer Miller, Joseph W. Foster, David C. Tigwell, David Cornwell
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Publication number: 20120081132Abstract: An apparatus includes a member including a ferromagnetic material, an inductance-capacitance resonant circuit, a substrate disposed relative to the member, and a plurality of radiation sources. The member includes a post disposed at its center and a surface extending to an outer wall. The member defines a gap between the post and the outer wall. The inductance-capacitance resonant circuit is configured to resonate at a measurement frequency. The circuit includes an inductor disposed relative to the post. The substrate is disposed relative to the member. The substrate is electromagnetically coupled to the inductor. The plurality of radiation sources is disposed radially outward from and circumferentially around the post of the member. The apparatus can be used to simultaneously measure conductance (inverse sheet resistance), steady state photoconductance, true steady state minority carrier lifetime, photoconductance build-up and photoconductance decay lifetime.Type: ApplicationFiled: April 5, 2011Publication date: April 5, 2012Applicant: MKS Instruments, Inc.Inventors: Francisco Machuca, Ronald Chiarello, G. Lorimer Miller, Joseph W. Foster, David C. Tigwell
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Publication number: 20110169520Abstract: An apparatus for measuring minority carrier lifetime is provided. The apparatus includes a resonant circuit having an inductor and a capacitor and configured to resonate at a measurement frequency. The apparatus also includes a ferromagnetic core having a first portion and a second portion. The first portion defines a gap and can be configured to direct therealong a magnetic field established by the inductor, such that lateral spreading of the magnetic field outside of the first portion is inhibited, and to direct the magnetic field generally uniformly across the gap. The second portion can be configured to direct the magnetic field therealong and, in conjunction with the first portion, into a closed loop. A radiation source can be configured to irradiate an area proximal to the gap defined by the first portion of the ferromagnetic core.Type: ApplicationFiled: January 14, 2010Publication date: July 14, 2011Applicant: MKS INSTRUMENTS, INC.Inventors: G. Lorimer MILLER, Joseph W. FOSTER, David C. TIGWELL
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Publication number: 20090274313Abstract: The present application is directed to an omnidirectional sound emitting device comprising an acoustic slotted waveguide array; and an acoustic source in communication with the acoustic slotted waveguide array. The device is configured to project an acoustic beam at distance up to about two nautical miles or more.Type: ApplicationFiled: May 5, 2008Publication date: November 5, 2009Inventors: W. Richard Klein, Domingo Castro, JR., David C. Tigwell
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Patent number: 6021319Abstract: A remote control system having a universal transmitter capable of being programmed to match the frequency and modulation pattern of any pulse modulated remote control transmitter. The system combines the universal transmitter and a separate apparatus for programming the universal transmitter. The programming unit detects the frequency and modulation pattern transmitted by a selected transmitter. The programming unit transfers the detected modulation pattern to the universal transmitter. The universal transmitter is operative to transmit the frequency detected by the programming unit. The universal transmitter thus duplicates the transmission of the selected transmitter. The system, apparatus and methods of this invention are particularly well adapted for application to low cost remote control transmitters permanently installed in vehicles.Type: GrantFiled: November 14, 1994Date of Patent: February 1, 2000Assignee: Colorado Meadowlark CorporationInventor: David C. Tigwell
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Patent number: 5818735Abstract: A method and system of measuring the differential time of flight of a signal transmitted between first and second transducers. First, multiple broadband signal pulses are transmitted in a first direction by the first transducer and received by the second transducer. Then, the received pulses are averaged to form a first received waveform. Next, multiple identical pulses are transmitted in a second direction and the received pulses are again averaged to form a second received waveform. Then, the first and second waveforms are cross-correlated. The peak of the cross-correlation data identifies a coarse measurement of the differential time of flight of the signal. Also, multiple sinusoidal signal pulses are transmitted in each direction and averaged, thereby creating third and fourth received waveforms. A first point is selected on the third waveform and first phase information is generated from a Fourier transform of the center frequency vector beginning at the first point.Type: GrantFiled: June 20, 1996Date of Patent: October 6, 1998Assignee: Peek Measurement, Inc.Inventors: David C. Tigwell, Athanassios Kontos, Seth Andrew Cocking
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Patent number: 5379453Abstract: A remote control system having a universal transmitter capable of being programmed to match the frequency and modulation pattern of any pulse modulated remote control transmitter. The system combines the universal transmitter and a separate apparatus for programming the universal transmitter. The programming unit detects the frequency and modulation pattern transmitted by a selected transmitter. The programming unit transfers the detected modulation pattern to the universal transmitter. The universal transmitter is operative to transmit the frequency detected by the programming unit. The universal transmitter thus duplicates the transmission of the selected transmitter. The system, apparatus and methods of this invention are particularly well adapted for application to low cost remote control transmitters permanently installed in vehicles.Type: GrantFiled: January 18, 1994Date of Patent: January 3, 1995Assignee: Colorado Meadowlark CorporationInventor: David C. Tigwell
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Patent number: 5227780Abstract: A plurality of infrared controlled appliances are controlled from a single UHF radio transmitter remote controller. The controller provides a plurality of separate distinct output control signals to an UHF to infrared transponder. The transponder has a UHF receiver, an infrared receiver, and an infrared transmitter. In one mode of operation, the transponder stores a received infrared signal and correlates it with a received UHF signal. In the operational mode, the transponder transmits a stored infrared signal through the infrared transmitter upon receiving a correlated UHF signal.Type: GrantFiled: October 16, 1991Date of Patent: July 13, 1993Assignee: Houston Satellite Systems, Inc.Inventor: David C. Tigwell
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Patent number: 5077561Abstract: A computerized antenna mount system for continuously tracking a satellite in geosynchronous orbit that has an inclined orbit with respect to the equator. An antenna mount that automatically adjusts the declination angle of a ground station satellite antenna as a function of time after iteratively compiling the declination angle history from one complete orbit of a satellite. Different satellite orbits may be so compiled with selection of each satellite and its corresponding orbit information from memory.Type: GrantFiled: May 8, 1990Date of Patent: December 31, 1991Assignee: HTSInventors: W. Daniel Gorton, James Burr, Timothy Morris, David C. Tigwell, Michael Cavanaugh
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Patent number: 4769629Abstract: An apparatus for actuating and deactuating a brake light affixed to a motorcyclist's helmet without any interface to the motorcycle. The apparatus illuminates and extinguishes the light by sensing the acceleration and deceleration forces.Type: GrantFiled: August 20, 1987Date of Patent: September 6, 1988Assignee: John N. Stone, Jr.Inventor: David C. Tigwell
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Patent number: 4620190Abstract: A method and apparatus for causing a plurality of navigational lanterns, each equipped with an independent light sensing device and connected to a common synchronizing terminal, to actuate simultaneously at dusk, and deactuate simultaneously at dawn. The light sensing device senses the three levels of day, twilight and night. When a sensing device senses day, the connected lantern is disabled from flashing and is disabled from sending a synchronizing signal to other lanterns to flash. When a sensing device senses twilight, the connected lantern is enabled to receive the synchronizing signal, but is disabled from sending a synchronizing signal. When the sensing device senses night, the connecting lantern is enabled and a synchronizing signal to flash is sent to all of the lanterns.Type: GrantFiled: July 30, 1984Date of Patent: October 28, 1986Assignee: Tideland Signal CorporationInventors: David C. Tigwell, Marion L. Recane
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Patent number: 4288206Abstract: A water sampler for delivering simultaneous multiple samples in which the samples are taken and discharged by a plurality of glass chambered syringes driven by a crank with water flow being controlled by a glass chambered valve having a valve spool shifted under the control of the crank.Type: GrantFiled: August 15, 1979Date of Patent: September 8, 1981Inventors: David C. Tigwell, David J. Schaeffer
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Patent number: D347637Type: GrantFiled: October 18, 1990Date of Patent: June 7, 1994Assignee: Houston Satellite Systems, Inc.Inventors: Peter C. Burchardt, David C. Tigwell, Robert A. Luly