Electric Power Research Institute Incorporated

Lucent Technologies Inc.

At+t Corp.

General Dynamics Advanced Technology Systems, Inc.

General Dynamics Advanced Technology Services, Inc.

Att Corp--lucent Technologies Inc

Michael H Silverberg

Jack F Trezza

John C Kiss

John F Rossi

Roger David Benning

Michael Anthony Zuniga

Woodson Dale Wynn

David Robert Smith

Garrett S Sylvester

Norman B Thompson

An adaptive controller is used to adaptively generate vibration cancellation signals driving a controlled device which effects an associated vibration and noise-producing plant. The adaptive controller has multiple control paths to generate the control signal. In a vibration attenuation control path(s), an adaptive control signal is generated by plant compensation and adaptive filtering techniques to cancel vibrations. In a position control, saturation prevention path, the available operational extents of the controlled device are monitored and compensation signals are generated which direct the movement of the controlled device in such a manner as to prevent the controlled device from reaching the extents of control. The control signals from the multiple paths are then combined and transmitted to the controlled device which alters in some fashion the noise and vibration being generated or transmitted by the associated vibrating plant.

System for control of active system for vibration and noise reduction

A multidimensional feedback system is used to reduce the noise component of a vibrational or acoustic field. The feedback algorithm includes a matrix operator that diagonalizes the feedback system. As a consequence, each of two or more actuators can be treated as though it closes an independent, one-dimensional feedback system. Therefore, classical one-dimensional feedback analysis can be used in the context of a system having multiple error sensors and multiple actuators.

Feedback method of noise control having multiple inputs and outputs

A ground voltage reduction device is connected between a neutral reference node and a ground node defined by two bypass capacitors of a blocking circuit. The ground voltage reduction device senses the voltage difference between the neutral reference node and the ground node and drives the ground node to reduce the voltage difference between a voltage of the ground node and a voltage of the neutral reference node.

Active ground compensation

A method of pinpointing the location between manholes of a fault in an electrical cable typically buried underground in an urban environment, the fault being caused by an insulation defect which may be broken down by a high voltage includes the steps of applying the voltage to break down the fault insulation defect to induce a transient fault pulse on the cable on both sides of the fault traveling away from the fault. By the use of a ferrite type transformer coupler producing an output voltage, the direction of the transient fault pulse is determined by relating the polarity of the output voltage to the initial high voltage pulse which was applied.

Method of locating a fault in an electric power cable

There is provided a system and method for locating faults in power distribution systems with complex topology, such as multi-phase urban networks (6), utilizing reliable time-delay techniques as well as a transponder (22) at a monitoring point to sense the arrival of the transient fault pulse and for transmitting a timing pulse a known time delay after sensing the arrival of the transient fault pulse and a calibration pulse a known time delay after transmitting the timing pulse. Installed along the power distribution system at key locations are receiver stations (4, 4a, 4b) capable of sensing the arrival of the transient fault pulse, timing pulse and calibration pulse and measuring the time intervals occurring between each. The location of the fault is then determined based on these timing intervals, known time delays and the known propagation velocity of the electric power cables in the power distribution system. Fault location accuracy is further enhanced by factoring rise-time effects of the sensed pulses into the time interval measurements.

System and method for locating faults in electric power cables

A telephone handset outbound noise canceller uses an omnidirectional reference microphone placed near the transmitter grille. Two adaptive filters are employed, one driven by the handset transmitter to subtract speech from a reference value to produce an enhanced reference signal; and a second adaptive filter driven by the enhanced reference signal to subtract noise from the transmitter. The weights of the two adaptive filters are allowed to adapt or are frozen according to criteria set as a result of transmitter power measurements which determine whether speech is likely to be present or not.

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Livingston, NJ, United States of America

Michael H Silverberg