James C Mathews

US Patent:

20130079027, Mar 28, 2013

Filed:

Sep 23, 2011

Appl. No.:

13/242710

Inventors:

Alan Jeffrey Hand - Tarzana CA, US
James Kirk Mathews - Hidden Hills CA, US

Assignee:

Xirrus, Inc. - Thousand Oaks CA

International Classification:

H04W 24/00

US Classification:

4554561

Abstract:

A system for quantifying the shadow fading observed in a wireless environment having multiple wireless access points is also provided. A distance determination module is in signal communication with the wireless access points. The distance determination module determines a distance between a pair of the wireless access points based on location information that relates to the locations of the wireless access points at the wireless environment. A shadow fading determination module is also in signal communication with the wireless access points. The shadow fading determination module determines a shadow fading factor based on the distance between a pair of the wireless access points and based on RSS information received from one of the wireless access points in the pair of wireless access points.

US Patent:

42517648, Feb 17, 1981

Filed:

Apr 26, 1979

Appl. No.:

6/033453

Inventors:

James K. Mathews - Van Nuys CA

Assignee:

Pertron Controls Corporation - Canoga Park CA

International Classification:

H02H 7127

US Classification:

323320

Abstract:

An interface circuit is provided for interconnecting an electronic controller to a contactor circuit which, in turn, controls the alternating current flow from an alternating current power source to controlled equipment, such as a resistance welding machine. The contactor circuit, for example, includes a pair of semiconductor switching devices, such as silicon controlled rectifiers (SCR)s, the two semiconductor switching devices are alternately rendered conductive during successive half-cycles of the alternating current power from the alternating current power source at times controlled by the controller for the controlled operation of the welding machine. The interface circuit includes means for monitoring the junction temperature of each of the semiconductor switching devices, and to provide an indication and a control effect should the junction temperature exceed a particular safe threshold.

US Patent:

43885152, Jun 14, 1983

Filed:

Mar 19, 1981

Appl. No.:

6/245261

Inventors:

James K. Mathews - Van Nuys CA

Assignee:

Pertron Controls Corporation - Canoga Park CA

International Classification:

B23K 1124

US Classification:

219110

Abstract:

A control system for use with a welding machine controller is provided which senses the dynamic resistance of the weld being formed by the welding machine, and which generates appropriate signals indicating the condition of the weld, which signals may be used for automatically controlling the operation of the controller. The control system of the invention senses the power factor in the primary circuit of the welding transformer included in the welding machine which is a measure of the dynamic resistance of the weld being formed, and the control system produces signals indicating the dynamic resistance of the weld, which signals may be digitized to produce appropriate control signals for the controller.

US Patent:

40399281, Aug 2, 1977

Filed:

Jul 19, 1976

Appl. No.:

5/706608

Inventors:

Russell Noftsker - Woodland Hills CA
James Kirk Mathews - Van Nuys CA

Assignee:

Pertron Controls Corporation - Van Nuys CA

International Classification:

G05D 2324
H05B 102

US Classification:

323 19

Abstract:

An operating circuit for a semiconductor switch device of the type that passes electrical current from a source to an electrical load by forward biasing of the semiconductor's control terminal includes a resistance bridge network having in an arm thereof the control terminal to one main terminal circuit of the semiconductor switch, and a bias control for alternately applying forward bias and reverse bias to the control terminal through the bridge network, whereby a voltage is developed across the bridge output during the interval in which the control terminal is reverse biased that is representative of the junction temperature within the semiconductor. The temperature representative voltage is observed, monitored, and used for indication and control. In a further embodiment the bias control operated periodically and includes inhibit means responsive to the derived temperature representative voltage exceeding a certain level, representative of a temperature maximum, for retaining the control terminal of the semiconductor in the back biased condition, until the derived voltage reduces in level thereby protecting the semiconductor from thermal burn-out. In a welding control circuit presented herein the foregoing bias control is adapted in an intra-phase control circuit.

US Patent:

43013511, Nov 17, 1981

Filed:

Apr 13, 1979

Appl. No.:

6/029752

Inventors:

James K. Mathews - Van Nuys CA

Assignee:

Pertron Controls Corporation - Van Nuys CA

International Classification:

B23K 1124

US Classification:

219114

Abstract:

A precision resistance welding machine controller is provided which may be set to deliver welding power to each of a multiplicity of welding operations on a precisely controlled repeatable basis. The controller of the invention is modular in nature and is microprocessor controlled. The controller includes a master control module which is standard for all models, and the master control module incorporates certain control circuits including a circuit for assuring that an accurately controlled amount of power is delivered for each welding operation. This is achieved by providing precise phase angle control despite variations in line voltage, and line noise disturbances. The controller also includes a personality module which is constructed for a particular welding operation, and which is programmed to incorporate any selected number of steps to be performed in sequence by the welding machine controlled thereby in carrying out the particular welding operation. The duration of each step of the welding machine, and the amount of welding power to be delivered, is set for the particular welding operation by adjustable controls on the personality module. The master control module of the controller of the invention also includes circuitry and controls for providing a self-test capabiliity for the controller.

US Patent:

20160127917, May 5, 2016

Filed:

Jun 9, 2015

Appl. No.:

14/734805

Inventors:

- THOUSAND OAKS CA, US
JAMES KIRK MATHEWS - HIDDEN HILLS CA, US

International Classification:

H04W 16/24
H04W 64/00
H04L 12/24
H04W 24/08
H04B 17/318

Abstract:

A system for quantifying the shadow fading observed in a wireless environment having multiple wireless access points is also provided. A distance determination module is in signal communication with the wireless access points. The distance determination module determines a distance between a pair of the wireless access points based on location information that relates to the locations of the wireless access points at the wireless environment. A shadow fading determination module is also in signal communication with the wireless access points. The shadow fading determination module determines a shadow fading factor based on the distance between a pair of the wireless access points and based on RSS information received from one of the wireless access points in the pair of wireless access points.

US Patent:

20150098407, Apr 9, 2015

Filed:

Jul 29, 2014

Appl. No.:

14/446091

Inventors:

- Thousand Oaks CA, US
James Kirk Mathews - Hidden Hills CA, US

International Classification:

H04W 72/08

US Classification:

370329

Abstract:

A channel allocation system for allocating channels in a frequency band to a plurality of radios in close proximity so as to minimize co-channel interference. One method for allocating channels involves initially tuning each of the plurality of radios to the same one of the plurality of channels. All of the radios then receive signals from whatever sources and a signal score is determined for each radio. The radios are then tuned to another one of the plurality of channels. The steps of receiving a signal and determining a signal score for each radio are repeated for each of the remaining channels until all channels have been used. The signal scores are then tested against a table of mapping schemes to determine maximum isolation.