Thomas M Hartnett

US Patent:

6754295, Jun 22, 2004

Filed:

Apr 7, 2000

Appl. No.:

09/545375

Inventors:

Thomas Hartnett - Westford MA

Assignee:

Comrex Corporation - Devens MA

International Classification:

H04L 700

US Classification:

375356, 375355

Abstract:

In one embodiment, the invention is directed to methods and system for converting an analog signal to digital samples for transmission over a communication network, and for converting digital samples received over a communication network to an analog signal. According to one feature, the system of the invention generates encoding and decoding master clocks from local oscillators, thus enabling the system of the invention to operate in environments where reliable timing signal are not available from the communication network. According to another feature, the system of the invention adjusts the frequencies of the encoding and decoding master clocks based on a connect rate to the communication network. In a further feature, the system of the invention employs encoding and decoding buffers for buffering the digital samples between a modem or a digital network access device, and signal converters to maintain a defined time relationship between digital samples being transferred between the modem or the digital network access device and the signal converters.

US Patent:

8211356, Jul 3, 2012

Filed:

Jul 18, 2000

Appl. No.:

09/618741

Inventors:

Thomas M. Hartnett - Nashua NH, US
Joseph M. Wahl - Lexington MA, US

Assignee:

Surmet Corporation - Burlington MA

International Classification:

C04B 35/10

US Classification:

264663, 264681, 423385, 423630

Abstract:

A method of making aluminum oxynitride includes introducing a mixture having aluminum oxide and carbon into a chamber, agitating the mixture within the chamber, and heating the mixture to make aluminum oxynitride.

US Patent:

20120225767, Sep 6, 2012

Filed:

Mar 4, 2011

Appl. No.:

13/040555

Inventors:

Jiyun C. Imholt - Methuen MA, US
Richard L. Gentilman - Acton MA, US
Thomas M. Hartnett - Nashua NH, US

International Classification:

G02B 1/00
C04B 35/00

US Classification:

501 1, 264 121

Abstract:

In accordance with the present embodiment, a method for making an optical ceramic comprises depositing a plurality of thin layers of powder. The powder comprises a first optical material powder having a first dopant level, and a second optical material powder. The first and second optical material powders are deposited for each layer based on the first dopant level and according to data associated with a three-dimensional (3D) compositional profile design of an optical ceramic. The method further comprises binding the first and second optical material powders of each thin layer to each other and each thin layer with an adjacent layer such that a green state optical ceramic is produced based on the 3D compositional profile design. The method further comprises densifying the green state optical ceramic to obtain the optical ceramic.

US Patent:

44813007, Nov 6, 1984

Filed:

Jan 13, 1984

Appl. No.:

6/570420

Inventors:

Thomas M. Hartnett - Nashua NH
Richard L. Gentilman - Acton MA
Edward A. Maguire - Ashland MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

C04B 3558

US Classification:

501 98

Abstract:

A method of preparing substantially homogeneous aluminum oxynitride powder is provided comprising the steps of reacting gamma aluminum oxide with carbon in the presence of nitrogen, and breaking down the resulting powder into particles in a predetermined size range. A method of preparing a durable optically transparent body from this powder is also provided comprising the steps of forming a green body of substantially homogeneous cubic aluminum oxynitride powder and sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron, in elemental or compound form, and at least one additional element selected from the group of yttrium and lanthanum or compounds thereof. The sintered polycrystalline cubic aluminum oxynitride has a density greater than 99% of theoretical density, an in-line transmission of at least 50% in the 0. 3-5 micron range, and a resolving angle of 1 mrad or less.

US Patent:

46860703, Aug 11, 1987

Filed:

Oct 29, 1984

Appl. No.:

6/665463

Inventors:

Edward A. Maguire - Ashland MA
Thomas M. Hartnett - Nashua NH
Richard L. Gentilman - Acton MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

C04B 3558

US Classification:

264 12

Abstract:

A method of preparing substantially homogeneous aluminum oxynitride powder is provided comprising the steps of reacting gamma aluminum oxide with carbon in the presence of nitrogen, and breaking down the resulting powder into particles in a predetermined size range. A method of preparing a durable optically transparent body from this powder is also provided comprising the steps of forming a green body of substantially homogeneous cubic aluminum oxynitride powder and sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron, in elemental or compound form, and at least one additional element selected from the group of yttrium and lanthanum or compounds thereof. The sintered polycrystalline cubic aluminum oxynitride has a density greater than 99% of theoretical density, an in-line transmission of at least 50% in the 0. 3-5 micron range, and a resolving angle of 1 mrad or less.

US Patent:

20220259107, Aug 18, 2022

Filed:

Jan 25, 2022

Appl. No.:

17/648921

Inventors:

- Waltham MA, US
Stephanie Silberstein Bell - North Andover MA, US
Christopher S. Nordahl - Littleton MA, US
Thomas M. Hartnett - Nashua NH, US
Richard Gentilman - Acton MA, US
R. Wesley Jackson - Mystic CT, US

International Classification:

C04B 35/505
C04B 35/04
C04B 35/626

Abstract:

A nanocomposite optical ceramic (NCOC) material. The material having a first solid phase, a second solid phase, and a third solid phase. The first solid phase has first solid phase grains no larger than 5 μm, and each first solid phase grain has a first solid phase grain boundary. The second solid phase has second solid phase grains no larger than 5 μm, and each second solid phase grain has a second solid phase grain boundary. The third solid phase has a doping agent. The doping agent is less than 5 atomic % soluble in the first solid phase and the second solid phase. At least part of the third solid phase is situated at the second solid phase grain boundary.

US Patent:

20230052113, Feb 16, 2023

Filed:

Aug 11, 2021

Appl. No.:

17/399510

Inventors:

- Waltham MA, US
Gerhard Sollner - Lincoln MA, US
Jason D. Adams - Medway MA, US
Poornima Varadarajan - Westford MA, US
Thomas M. Hartnett - Nashua NH, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

H01P 1/22
H01P 1/203
H03H 7/01

Abstract:

Methods and apparatus for a frequency selective limiter (FSL) having a magnetic material substrate that tapers in thickness and supports a transmission line that has segments and bends. The segments, which differ in width and are substantially parallel to each other, such that each segment traverses the substrate on a constant thickness of the substrate.

US Patent:

20210221742, Jul 22, 2021

Filed:

Jun 11, 2020

Appl. No.:

16/899272

Inventors:

- Waltham MA, US
Thomas M. Hartnett - Nashua NH, US

International Classification:

C04B 35/505
C04B 35/04
G01J 1/04
G01J 1/42

Abstract:

Various embodiments disclosed relate to an optical window including an infrared light transmissive optical material. The optical material includes a first ceramic phase including a first ceramic material and a first dopant distributed therein. The optical material further includes a second ceramic phase homogenously intermixed with the first ceramic phase and comprising a second ceramic material and a second dopant distributed therein. The first dopant increases the refractive index of the first ceramic material and the second dopant decreases the refractive index of the second ceramic material. The first dopant and the second dopant are present in an amount such that a difference in a refractive index of the first ceramic phase and of the second ceramic phase is in a range of from about 0.001 to about 0.2.