Kenneth F Holt

US Patent:

6486679, Nov 26, 2002

Filed:

Jan 21, 2002

Appl. No.:

09/683574

Inventors:

Kenneth David Holt - Dallas TX 75248

International Classification:

G01R 2702

US Classification:

324610, 324706

Abstract:

A radio frequency bridge, useful for measuring complex values of an unknown impedance or associated complex reflection coefficient and VSWR value, which comprises an rf source, a novel asymmetrical bridge, a measuring device (comprising two logarithmic amplifiers, a difference amplifier and a phase detector), a computing device and a display or interface device. The complex impedance may be any two terminals of a general N-port network not to exclude an antenna with or without feed-line. The invention is more accurate than prior art when measuring complex impedance values having magnitudes from approximately five ohms to an upper value limited only by the dynamic range of the logarithmic amplifiers, normally greater than 4000 ohms. It has the great advantage of maintaining constant measuring accuracy over a wide measuring range and can be designed to operate over very wide bandwidths.

US Patent:

61119733, Aug 29, 2000

Filed:

May 29, 1997

Appl. No.:

8/864748

Inventors:

Kenneth Dale Holt - Midlothian TX
David Michael Holt - Midlothian TX

International Classification:

G06K 900

US Classification:

382100

Abstract:

Disclosed is a method of producing color-comparable photographs with which a prosthetic fabrication artist can determine whether photographs taken of an amputee's extremity are color-true and whether recorded color selections, matching pre-designated areas of the extremity, were accurately chosen. A prosthetic technician, or another skilled in the art, takes color photographs of an amputee's extremity on a duplicate copy of a colored background which has a neutral colored central area and a perimeter band of various human fleshtone or skin colors. The technician matches certain colors in the perimeter color-band to pre-designated areas of the extremity and records them on a color selection diagram. The photographs and color selection diagram are forwarded to the fabricating artist who uses them to determine the proper coloration of a prosthetic restoration by comparing the colored background shown in the photograph with a second duplicate copy of the colored background in the possession of the fabricating artist.