Abstract: A simple, passive and rugged device for measuring the flow rate of liquid. A variable area obstruction valve, a differential pressure sensor and a densitometer are combined in a single housing to provide for a highly accurate and precise measure of mass flow.

Abstract: A passive RFID transponder sensor system includes a sensor assembly having a focused field transponder antenna with a highly magnetically permeable transponder antenna stem, and a reader antenna with an electrical reader coil generating a magnetic field having magnetic flux extending between the reader antenna and a sensor assembly. The electrical transponder coil and the electrical reader coil are coupled by the magnetic field, so that information can be transferred to and from the sensor assembly through the magnetic field by which the electrical transponder coil and the electrical reader coil are coupled.

Abstract: Three coils, each having several serial windings, have selected windings connected in a delta. Input AC power is applied through outrigger windings at the delta apices. At least two strategically located, direct tap, natural output points are provided at each side of the delta. For 6-phase output, only the six natural output points are required. For 9-phase output, an additional central output terminal connects to each side of the delta through a stub winding. The 6-phase or 9-phase output is passed to a rectifier circuit.

Abstract: A plurality of pressure sensors are provided in a tire of an aircraft landing gear, such sensors being carried by the same stem assembly that has the inflation-deflation valve for the tire. A communication microcircuit is provided in the stem. The communication microcircuit is connected to one coil of a stem transformer, with the other coil of the stem transformer being electrically connected to one coil of an axle transformer. The other coil of the axle transformer is coupled to an axle communication circuit which powers the axle and stem circuits and polls the sensors to determine tire pressure.

Abstract: A target device is carried by or mounted on a first part movable relative to a second part. The second part has a sensing device including an array of sensors providing outputs responsive to the magnet field of the target device. A processing device receives the outputs of the sensors and calculates relative positions of the two parts based on the outputs.

Abstract: A core of a proximity sensor is made of a highly permeable metal and is shaped and sized to operate as a saturable core proximity sensor, a variable reluctance proximity sensor, and an eddy current proximity sensor. The core has a cross-sectional shape including a head portion, two legs extending from the head portion, and two foot portions (feet) extending from the two legs. The head portion forms a substantially planar section along the upper surface and is perpendicular to the sectional direction created by the two legs. The sectional direction of the two legs are perpendicular to the sectional direction of the two feet. The two feet are in a common plane along the bottom surface. Both foot portions are also parallel to the head portion. The cross-sectional shape of the core may further comprises two tail portions (tails), wherein each tail extends from one of the two foot portions in a direction toward the upper surface.

Abstract: An omega-shaped core is wrapped with two coils arranged to be responsive to magnetic permeable metal and conductive metal objects. The omega core allows the proximity sensor to operate as a saturated core sensor, a variable reluctance sensor or an eddy current loss sensor. The core is made from a thin, highly permeable metal that is preferably formed from a single piece of sheet metal, and comprises a substantially flat, rectangular member bent in four locations to form a head portion, two legs, and two feet. The bends form right angles so that the head portion is perpendicular to the two legs, and the two legs are perpendicular to the two feet. The two feet are parallel to each other and also parallel to the head portion. The core is positioned in a housing with two inductive coils, each coil being positioned around a leg portion of the core. A calibration bolt can be placed through the center of the core to change the level of inductance measured from the two inductive coils.

Abstract: A core of a proximity sensor is made of a highly permeable metal and is shaped and sized to operate as a saturable core proximity sensor, a variable reluctance proximity sensor, and an eddy current proximity sensor. The core has a cross-sectional shape including a head portion, two legs extending from the head portion, and two foot portions (feet) extending from the two legs. The head portion forms a substantially planar section along the upper surface and is perpendicular to the sectional direction created by the two legs. The sectional direction of the two legs are perpendicular to the sectional direction of the two feet. The two feet are in a common plane along the bottom surface. Both foot portions are also parallel to the head portion. The cross-sectional shape of the core may further comprises two tail portions (tails), wherein each tail extends from one of the two foot portions in a direction toward the upper surface.

Abstract: An optimizer circuit is interposed between a DC bus and a battery of a power supply system, including two converters in parallel, one that can lower the battery voltage below the bus voltage or directly connect the bus to the battery and one that can raise the voltage to the battery above the bus voltage. A controller actuates the two converters for optimizing battery charging and maintenance and for providing the battery power to the bus if other sources supplying the bus are not available.

Abstract: A regulator circuit (10, 50) is connected to a high voltage generator (16, 52). The regulator circuit may be coupled to the generator in either a series or a shunt configuration. In the shunt configuration, the regulator circuit (10) varies the amount of current through a shunt resistor (R1) to change the output voltage provided to a load. The amount of current that is shunted by the regulator circuit is controlled by a feedback circuit consisting of a voltage divider (20) and an error amplifier (22). In the series configuration, the voltage across the regulator circuit (50) is added to the output from the high voltage generator. The current conducted through the regulator circuit therefore varies the summed output provided to the load.

Abstract: A driver (10) produces a current to generate traveling waves of voltage for low levels of illumination and an arc voltage for high levels of illumination through a gas discharge lamp (50). At the low illumination levels the traveling waves of voltage are produced in a manner so as to increase the current in the lamp at a controlled rate so that the increase in current can be stopped by an optical or ionization feedback loop when the lamp reaches the glow discharge region, after the Townsend discharge region and before the arc discharge region. Without careful control of the rate of the current increase, the desired current level can easily be overshot or undershot. Also, the feedback is critical given the varying nature of the impedance of gas discharge lamps. The process is repeated at selected intervals to produce a desired average level of illumination.

Abstract: A regulator circuit (10, 50) for connection to a high voltage generator (16, 52). The regulator circuit may be coupled to the generator in either a series or a shunt configuration. In the shunt configuration, the regulator circuit (10) varies the amount of current through a shunt resistor (R1) to change the output voltage provided to a load. The amount of current that is shunted by the regulator circuit is controlled by a feedback circuit consisting of a voltage divider (20) and an error amplifier (22). In the series configuration, the voltage across the regulator circuit (50) is added to the output from the high voltage generator. The current conducted through the regulator circuit therefore varies the summed output provided to the load.

Abstract: A switching circuit (50) comprising cascaded transistor stages (52a, 52b. . . 52n and 54), connected between a high voltage terminal (62) and a sense resistor (RS) coupled to a low voltage terminal (64). The transistor stage (54) closest to the sense resistor (RS) is referred to as a current gain stage (54), and all the other transistor stages (52a, 52b. . . 52n) are referred to as component stages (52a, 52b. . . 52n). Blocking diodes (DD) are connected across all stages (52a, 52b. . . 52n and 54), forming a continuous path between the high voltage terminal (62) and the low voltage terminal (64). When an enable signal is provided to the current gain stage (54), the transistor stages (52a, 52b. . . 52n and 54) sequentially enter conduction, beginning with the current gain stage (54) and proceeding through the component stages (52a, 52b. . . 52n). As each transistor stage (52a, 52b. . .

Abstract: A resonant power converter holds energy within the circuit for a variable period to provide fixed-frequency, zero-voltage switching power conversion. A first switch alternately connects and disconnects a DC voltage source to one side of the primary winding of the transformer of a power converter. A second switch is connected between the other side of the primary winding and ground. A switch controller is responsive to the difference between a reference voltage and the voltage level present at the output of the circuit associated with the secondary winding of the transformer. Energy is added to the circuit while the first and second switches are closed. The first switch is then opened and energy is held in the circuit for a variable period of time to delay the beginning of resonance. Finally, both switches are opened and the energy within the circuit resonates. The energy holding period is adjusted as necessary to maintain a fixed frequency with varying loads.

Abstract: An AC-to-DC converter and regulator normally receives power from an AC utility line and provides a stable DC output to a load, such as the power amplifier and transmitter of a cell site. The DC output, or a separate dedicated output from the converter, is used to charge a backup battery when AC power is available. If AC power is interrupted, the backup battery provides power to the load by way of a separate DC-to-DC differential converter. The battery is connected in parallel with the differential converter input, but in series with the differential converter output. Thus, the differential converter receives operating power from the battery, and outputs a voltage which is summed with the battery output to drive the load. A control circuit for the differential converter senses the voltage provided to the load, and supplies a signal to the differential converter to adjust its output as necessary to maintain the optimum aggregate output to the load.

Abstract: A free-space optical communications system for transmitting data between an aircraft computer system (14) and a ground-based computer system (12). The system includes a pair of corresponding optical transmitters (36) and optical receivers (38) that transmit and receive optical signals transmitted between the two computer systems. Included within each optical transmitter is one or more light-emitting diodes (42) that produce optical signals corresponding to the data to be transmitted. A beam-forming horn (44) is bonded directly to the light-emitting diodes to direct the optical signal uniformly over a target area. The optical receiver includes one or more infrared windows (50) to reduce the mount of ambient light received by the optical receiver. A compound parabolic concentrator (64) collects light transmitted from the optical transmitter and directs the light onto an avalanche photodiode (66), which includes thermal bias compensation.

Abstract: Cascaded transistor stages are connected between a high voltage and a resistance coupled to a lower potential. The transistor stage closest to the lower potential is referred to as a driver stage, and all the other transistor stages are referred to as component stages. When an enable signal is provided to the driver stage, the stages sequentially enter conduction, starting with the driver stage and proceeding to the component stage coupled to the high voltage. The current flow through the driver stage is regulated, proportional to the value of the series resistance, and remains relatively constant as the high voltage is brought to close to the lower potential. The voltage drop is smooth and approximately linear, ensuring that voltage ringing or rebound does not occur following the discharge.

Abstract: Disclosed is a method and system for unobtrusively measuring physical properties in electrochemical processes occurring in a predefined volume, such as the state of charge in an electrochemical battery. The invention provides for a coil (22) or (42) positioned relative to the predefined volume to minimize the reluctance path between the coil and the electrochemical process, with the winding axis of the coil generally transverse to a surface bounding the predefined volume. In this position, an alternating current is applied to the coil to generate an oscillatory magnetic field. Preferably, the coil includes a core (24) or a backing plate (46) for concentrating the magnetic field in a direction towards the process in the predefined volume. The physical properties are determined based upon a measurement of the electrical complex impedance of the coil, and data correlating the physical properties of the process with the electrical complex impedance of the coil.

Abstract: Pulse techniques are used to periodically monitor a desired environmental condition, such as pressure. A solid-state switch is connected between a power source and a load. In the off state of the switch, power from the source drives a timer circuit which supplies a short voltage pulse to a circuit for sensing the environmental condition. At the same time, the pulse is supplied to associated circuitry for temperature compensation, amplification of the resulting sensing circuit signal, and a comparator circuit which determines whether or not a signal of the condition sensed exceeds a predetermined threshold. If such signal exceeds the threshold, the solid-state switch is turned on to connect the voltage source to the load. Turning on the switch results in substantially eliminating the voltage drop between the switch terminals, which previously was used to actuate the timer.

Abstract: Disclosed is a method of designing a position sensor having a plurality of coils so that the total impedance of the sensor varies according to a desired impedance function. The method includes the steps of modelling the position sensor on a computer using a finite element analysis program to determine the vector potential and current density within the sensor due to a known current flowing in each of the coils. A set of matrix equations is then developed that relates vector potential, the current density and the number of turns, N.sub.i, in each coil to a point on the desired impedance function. The set of matrix equations is then optimized to determine the number of turns, N.sub.i, that each coil should contain, so that the total impedance of the sensor varies according to the desired impedance function.