Westinghouse Electric Corporation

United States of America As Represented by the Secretary of the Air Force

Northrop Grumman Systems Corporation

Charles W Einolf, Jr

Karl C Koch

Andras I Szabo

Robert M Oates

James A Neuner

Albert W Crew

Paul F Rozelle

Harvey C Nathanson

Peter Douglas Hill

Shan C Sun

James L McShane

Harold B Shutterly

Warren A Edblad

Roger W Heinig

Carlo F Petronio

Elbert L Cole, Jr

Carl J Staab

Francis S McKendree

Linda L Santoline

Roger E Ray

Jeff T Stringer

Russel W Gonnam

Pamela M Maynard-Nenno

Carlo F Peteronio

A coherent signal generated at a precise frequency determined by an atomic clock is transmitted by a moveable object. A receiver station compares the frequency of the coherent signal received from the moving object with a second coherent signal generated at the same precise frequency by an atomic clock in the receiver to determine the radial component of the velocity of the moveable object relative to the receiver as a function of the doppler shift of the transmitted signal. Low cost, low power, miniature atomic clocks with an accuracy of 10.sup.-11 make possible accurate measurements of velocities of only centimeters per second. Such velocity measurement can be used to enhance radar tracking in air traffic control and collision avoidance systems. These velocity measurements can also be used to resolve tracking ambiguities in precision location systems, such as prisoner, geriatric and airport ground control systems, where three or more receiver stations each having an atomic clock measure time of flight of the transmitted coherent signal to triangulate moving object position.

Location and velocity measurement system using atomic clocks in moving

Real time periodic messages generated by a plurality of stations on a data communication network and having data periods ranging from a shortest to a longest, where the longest data period is an integer multiple of all the others, are assigned by a server station to transmit time slots, equal in duration to the shortest data period, on a global basis to minimize the number of messages transmitted by all stations during each transmit time slot.

Global load smoothing in a real time data imaging network system

A communications network grid having a matrix of nodes at which transmitters or receivers are connected to transmit and receive signals from any origin or destination. Each node utilizes first come only served control logic to retransmit the first received signal.

First come only served communications network

A system and method are provided for monitoring synchronous blade vibration in a turbo-machine. At least three sensors capable of detecting the arrival of each blade are arranged about the cylinder which surrounds the tips of the blades. The location of the sensors is selected to minimize the influence of errors in the data. To this end, and to simplify the installation of the sensors into the cylinder, the sensors may be non-uniformly spaced. The location of each sensor for purposes of constructing Fourier transforms is determined using the arrival times at the blades at each sensor, expressed as a fraction of a rotor revolution. The transform matrix is constructed for a predetermined discrete set of M harmonics, so that M harmonics are analyzed simultaneously, the number of harmonics which can be simultaneously analyzed is related to the number of sensors used. The blade arrival time data at each sensor, expressed as a fraction of a rotor revolution, is analyzed to determine the amplitude of the blade vibration at each of the harmonics selected for the set. The calculations are repeated for a variety of harmonic sets in order to accurately interpret the results in the event there is significant vibration at harmonics not included in the initial set.

System and method for monitoring synchronous blade vibration

An apparatus for detecting turbine blade passing times includes a sensor for producing an input signal each time a blade passes the sensor. Automatic gain control circuitry including a digital multiplier, peak detector and error amplifier regulates the amplitude of the input signal. A zero-crossing detector produces an output signal each time the input signal crosses a reference axis. A pre-trigger comparator produces a gating signal coinciding with the expected arrival time of the blade at the sensor. A gating device is responsive to the gating signal for conducting output signals which occur during the expected arrival time of the blade at the sensor. A monostable vibrator produces a digital pulse coinciding with the time at which the blade passes the sensor.

Steam turbine blade arrival time processor with automatic gain control

An apparatus for detecting blade passing times includes a sensor for producing an input signal each time a blade passes the sensor. A zero crossing detector produces an output signal each time the input signal crosses a reference axis. A phase shifter shifts the phase of the input signal to produce a gating signal coinciding with the expected arrival time of the blade at the sensor. A gating device is responsive to the gating signal for conducting output signals which occur during the expected arrival time of the blade at the sensor.

Apparatus for precise detection of blade passing times in a steam turbine

The multiplexer in a multichannel, secure digital communication system repetitively embeds a sequence of byte length uniquely coded synchronizing signals in each of n successive frames of one channel of a multichannel, time multiplexed digital bit stream. Redundant protective relay data and associated parity check data are embedded in four of the n frames in a second, preferably adjacent channel, with the remaining of the n frames in the second channel containing additional of the uniquely coded synchronizing signals. The time multiplexed serial bit stream is transmitted to a remote station, preferably by fiber optic communications media. The most recent bits of the received serial bit stream equal in number to the number of bits spanned by the two channels in n frames are retained in n-1 serially connected serial in, serial out shift registers. Sixteen bit portions, a frame apart, of the retained most recent bits of the serial bit stream are applied to n serial in, parallel out shift registers. The parallel outputs of these shift registers corresponding to the frames of the two channels encoded with the synchronizing signals are compared with the sequence of uniquely coded signals stored in addresses in PROMs. When the compared signals match, which will occur once in every n frames, a synchronization signal is generated and the protective relay data and parity check data are read directly from the other parallel outputs of the serial in, parallel out shift registers. Similar rapid resynchronization of voice and data channels in the time multiplexed serial bit stream can be achieved by counting the number of bits in the bit stream from the generation of the synchronization signal in the relay protection channels to the beginning of the time slot for a selected voice or data channel.

Apparatus and method for secure digital communication

An optical receiver especially useful for digital fiber optic systems operating a high pulse rates, converts the pulsed current signal generated by a PIN diode into a pulsed voltage utilizing a current to voltage converter comprising an FET input transistor, a complimentary cascoded bipolar transistor, and a large feedback resistor to reduce noise while providing a wide band width and dynamic range. The pulsed voltage signal is amplitude limited in a limiting amplifier and passed through a low pass filter to remove excess bandwidth and further reduced noise before being applied to a high speed comparator which generates the digital output. The pulsed voltage signal is passed from the current to voltage converter to the limiting amplifier through an emitter follower coupling transistor to isolate the open loop gain of the current to voltage converter so that its band width will not be changed with load.

Fiber optic receiver

A circuit arrangement for monitoring ground faults to a normally ungrounded coil of a motor, the circuit arrangement including; a source of a low-level d.c. voltage, the source having first and second output terminals between which the d.c. voltage is established and a conductive connection being established between the first output terminal and the motor coil; a current responsive unit connected between a point at ground potential relative to the motor coil and the second output terminal of the source for producing an output signal proportional to the amplitude of current flow between the second terminal and ground; and a motor control unit connected for preventing operation of the motor when the output signal from the current responsive means reaches a selected value.

Resistance to ground checker

A serial data communications network in which a plurality of stations communicate among one another in an orderly and collision-free manner on a single serial bus. Each station incorporates an improved bus access circuit to operate in cooperation with the bus access circuit of every other station in the network. The resulting effect as to each station is the assignment of a unique, recurring time window during which the station may initiate a transmission on the serial bus exclusive of all other stations.

Bus access circuit for high speed digital data communication

A method is described for electrically converting an analog signal into a digital representation in a manner that maximizes noise rejection. The digital representation is formed from a preselected number of discrete points corresponding to sampled approximations of the analog signal. In establishing the magnitudes of the respective points, digital samples of the analog signal are taken at a predetermined number of discrete coordinates along the analog signal on either side of the respective discrete points. The predetermined number of coordinates are averaged and employed as corresponding approximations for the respective discrete points in the digital representative reproduction of the analog signal. The effects of harmonics of power line frequencies associated with processing electrical equipment are minimized by sampling the discrete coordinates for a particular point over an integral number of cycles of the power line frequency. In addition, noise having a high frequency, low duty cycle can be minimized by sampling a relatively large number of discrete coordinates over a period substantially greater than the occurrence of the noise.

Method of electrically converting an analog signal into a digital

Apparatus for electrically converting an analog signal into a digital

Encoding photocells are positioned in a circuit array for sensing lighted and unlighted variations produced by changes in an optical code pattern. Corresponding signal output changes of the encloding photocells are detected by being sequentially connected to a sensing network including a reference photocell circuit array. The encoding photocell output changes are sensed at a voltage comparator having inputs connected to the sensing network and a fixed voltage reference to produce a binary signal output. A comparator inhibiting circuit deactivates the comparator in response to a malfunction condition to protect against erroneous operation.

Growing community of inventors

Murrysville, PA, United States of America

Charles W Einolf, Jr