Thomas M Carroll

US Patent:

6370248, Apr 9, 2002

Filed:

Jul 31, 1998

Appl. No.:

09/126711

Inventors:

Thomas L. Carroll - Alexandria VA
Gregg A. Johnson - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H04L 926

US Classification:

380263, 380 46, 380260, 380262, 708300

Abstract:

A system for synchronizing chaotic transmitters and receivers that is less sensitive to channel effects than other known chaotic communication methods. The system employs duplicate transmitter and receiving modules and in addition to the chaotic output a synchronizing signal which occupies a reduced bandwidth. The small bandwidth affords the system a greater resistance to the affects of frequency dependent channel distortion and noise. The broad band chaotic signal is transmitted and appears to be noise to an unauthorized listener. The receiving unit employs band pass filtering, and when the signal is received the receiver filters the chaotic signal through band pass filters which eliminate channel noise and make gain control easier to implement.

US Patent:

6631166, Oct 7, 2003

Filed:

Dec 6, 1999

Appl. No.:

09/455167

Inventors:

Thomas L. Carroll - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H04L 2700

US Classification:

375259, 380 48, 380 9, 380 46, 380263, 331 78, 364717, 375364, 375367, 375359, 375316, 375343, 375377

Abstract:

A signal generator and signal receiver, as well as method of signal generation and transmission, in which selected unstable periodic orbits of a lossy chaotic system are identified and extracted, and portions of the orbits concatenated together to form a resultant signal. The selected orbits are known to the signal detector a priori. The signal detector detects the transmitted signal by correlation of the received signal with the known extracted orbits, also allowing the detector identify information which the generator imposed onto the signal.

US Patent:

6854058, Feb 8, 2005

Filed:

Apr 23, 2001

Appl. No.:

09/839146

Inventors:

Thomas L. Carroll - Alexandria VA, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G06F001/24

US Classification:

713168, 713200, 713201

Abstract:

The low-interference communications device uses chaotic signals which are almost periodic. A chaotic circuit driven by a sine wave signal from a function generator is produced which has narrow-band features in the power spectrum. An information signal is encoded on the chaotic signal by modulating the phase of the sine wave that drives the chaotic circuit. Periodic (narrow-band) components are then removed from the chaotic signal and the chaotic signal is transmitted to a receiver device. The chaotic signal is nonlinear, so the narrow band and broad band parts of the chaotic signal have been modulated together. The transmitted signal is relatively flat, so it will not interfere with other communications signals. At the receiver, the nonlinear chaotic signal is restored by performing a nonlinear operation on the received signal, such as squaring or cubing, to remove the narrowband components. Then the information modulated onto the narrow band component is detected.

US Patent:

8050141, Nov 1, 2011

Filed:

Nov 21, 2008

Appl. No.:

12/275355

Inventors:

Thomas L. Carroll - Alexandria VA, US
Graham K. Hubler - Highland MD, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01S 3/802

US Classification:

367124, 367906

Abstract:

A system and method is provided for estimating a trajectory of an incoming bullet based on the acoustics of the shock wave created as the bullet travels through the air. A first auditory signal representing a direct sound from the shock wave is recorded and its azimuthal direction is determined. Based on this azimuthal direction and other assumptions two possible bullet directions that can cause that shock wave are estimated. A second auditory signal representing a reflection of the shock wave as it travels through the air also is recorded and its azimuthal direction determined. The azimuthal direction of the ground reflection will lie between the azimuthal direction of the first auditory signal and the more correct of the two estimated trajectories, and thus can resolve the ambiguity in the estimated direction of the bullet source.

US Patent:

20050180522, Aug 18, 2005

Filed:

Feb 13, 2004

Appl. No.:

10/779553

Inventors:

Thomas Carroll - Alexandria VA, US

International Classification:

H04L027/20
H03D001/00

US Classification:

375295000, 375340000

Abstract:

A communications device includes a symbol encoder for receiving data comprising a symbol and for receiving a first signal having a positive entropy. The symbol encoder adds to the first signal a plurality of delayed versions of the first signal. Each delayed version of the plurality of delayed versions has a plurality of available values. The symbol is represented by a set of delay values, a delay value of the set of delay values including an available value of the plurality of available values for the each delayed version of the plurality of delayed versions. The communications device also includes a transmitter for receiving the encoded data from the symbol encoder and for transmitting the encoded data. For example, the first signal having positive entropy includes a chaotic signal, noise signal, or a positive entropy, baseband signal modulated onto a positive entropy signal having a higher frequency than the baseband signal. For example, the chaotic signal includes a Lorenz system-generated chaotic signal or a Rossler system-generated chaotic signal. The communications device supports bandwidth-efficient transmission in communications media.

US Patent:

56550227, Aug 5, 1997

Filed:

Sep 29, 1995

Appl. No.:

8/536027

Inventors:

Thomas L. Carroll - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H04L 912

US Classification:

380 48

Abstract:

A filtered cascaded synchronized nonlinear system includes a nonlinear transmitter having stable first and second subsystems. The first subsystem produces a first transmitter signal for driving the second subsystem, and the second subsystem produces a second transmitter signal for driving the first subsystem. A first filter filters the second transmitter signal to produce a filter output signal. A subtractor subtracts the filter output signal from the second transmitter signal to produce a transmitter output signal which is transmitted to a nonlinear cascaded receiver. The receiver includes an adder for summing the received transmitter output signal with a receiver filter output signal to restore frequencies that were subtracted from the second transmitter signal in order to produce a first receiver drive signal. The receiver includes cascaded third and fourth subsystems that are respective duplicates of the first and second subsystems. The third subsystem is driven by the first receiver drive signal to produce a first receiver signal in synchronization with the first transmitter signal.

US Patent:

54736943, Dec 5, 1995

Filed:

Jun 29, 1994

Appl. No.:

8/267696

Inventors:

Thomas L. Carroll - Alexandria VA
Louis M. Pecora - Alexandria VA
James F. Heagy - Greenbelt MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H04L 912
H04L 7033

US Classification:

380 48

Abstract:

A cascaded synchronized system includes a nonlinear transmitter, a nonlinear cascaded receiver, a phase-detector/controller coupled to the receiver, and a signal generator also coupled to the receiver. The transmitter is responsive to an externally generated transmitter forcing signal for producing and transmitting a chaotic communications signal containing phase information. The cascaded receiver is responsive to a receiver forcing signal and to the chaotic communications signal for producing a chaotic receiver output signal containing phase information. The phase-detector/controller is responsive to the chaotic communications signal and to the receiver output signal for producing a correction signal. The signal generator is responsive to the correction signal for producing the receiver forcing signal in phase with and having the same frequency as the transmitter forcing signal.

US Patent:

52456609, Sep 14, 1993

Filed:

Feb 19, 1991

Appl. No.:

7/656330

Inventors:

Louis M. Pecora - Alexandria VA
Thomas L. Carroll - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H03B 2900
G06F 102

US Classification:

380 48

Abstract:

A system for producing two synchronized signals comprises a nonlinear dynamical primary system and a nonlinear dynamical secondary response subsystem. The primary system comprises a nonlinear dynamical drive subsystem for producing at least one drive signal, and a nonlinear dynamical primary response subsystem responsive to said at least one drive signal for producing a primary signal, wherein said primary response subsystem has a complete set of at least one primary sub-Lyapunov exponents, all of said at least one primary sub-Lyapunov exponents being negative. The second response subsystem is responsive to said at least one drive signal for producing a secondary signal in synchronization with said primary signal, said secondary response subsystem being substantially a duplicate of said primary response subsystem, wherein said secondary response subsystem has a complete set of at least one secondary sub-Lyapunov exponents, all of said at least one secondary sub-Lyapunov exponents being negative.