Abstract: A system and method for injecting and canceling a bias voltage in an attenuated circuit is presented. The attenuated circuit is disposed within a tri-state logic-level measurement apparatus. The bias voltage is provided to ensure that when the measurement apparatus is floating, it floats at the tri-state voltage. In one embodiment, a summing network is connected to an attenuator, a first voltage generator which provides a bias voltage and a second voltage generator which provides a cancellation voltage. In another embodiment, a FET amplifier is provided in place of the summing network.

Abstract: A method for determining whether a circuit under test is open is presented. A digital-to-analog converter is dithered to generate a known signal. This known signal is summed with an external attenuation signal which is brought into the system from a probe on the circuit under test. This summation is then measured by an analog-to-digital converter (ADC). If the known signal is not attenuated by the probe (i.e., the ADC measures essentially the known signal), we can conclude that the circuit is open.

Abstract: A system for detecting open circuits is presented. The system comprises first and second digital-to-analog converters (DACs). The DACs, in combination with a microprocessor, generate a tri-state voltage which is fed through the system. This tri-state voltage is then attenuated via an amplifier. A probe carries an external attenuation signal via a measurement line through the system to be summed with the attenuated tri-state voltage to create V.sub.wts. An analog-to-digital converter then compares V.sub.wts with a known signal to determine whether the circuit under test is open.

Abstract: The multi-use sensor has a controllable number of measurement cycles. This multi-use sensor consists of a sensor and/or electrodes that are encased in a suitable material to allow reuse of the sensor and sensor life cycle circuitry that functions to regulate the number of operational cycles that the sensor can execute to ensure that the multi-use sensor is not used beyond its effective life. Included in this life cycle circuitry is a dual state mechanism that is connected across two conductors and that has a first state of low impedance. There is sensor state change apparatus that changes the state of the dual state mechanism to a second state of high impedance, such as an open circuit between the two conductors.

Abstract: A low power high efficiency power supply provides a high voltage level output, which can be used to drive a variety of devices. The power supply uses controlled feedback to a comparator, which in turn drives an AND gate logic device. The comparator drives the AND gate logic device to gate an input clock signal the output of the AND gate logic being supplied to a resonant circuit that is at or near the resonant frequency of the input clock signal. The output of the resonant circuit is rectified to provide the final voltage output. The final voltage output is attenuated and supplied as feedback to the comparator.

Abstract: A cup holder includes a movable adapter ring for use in selectively reducing the inner diameter of the larger upper socket that is the primary cup support. The large upper socket is movably secured to an underlying base member having an outer diameter sufficient to securely fit into the stationary cup holders found in most late model vehicles. The upper socket is movable in a lateral direction to accommodate use of two such supports in vehicle that provide two adjacently positioned cup holders.

Abstract: A passive ring resonator gyro is constructed of an electromagnetic waveguide ring path which causes a specified rotation of the polarization of the waves, once for each round trip through the ring path. For an optical fiber ring path, a splice at some point is introduced in the ring path in which the fiber ends are rotated relative to each other in order to effect polarization rotation.

Abstract: A threshold receiver circuit consists of a reference subcircuit and one or more signal input subcircuits. The reference subcircuit derives a mirror voltage by regulating a reference current flowing through an external reference resistor. The mirror voltage is distributed to each of the signal input subcircuits. Within each signal input subcircuit a signal transistor has its gate connected to the mirror voltage and its drain connected to a common input node, thereby causing a signal current to flow into the common input node which is proportional to the reference current. The signal current also flows through an external signal input resistor which is connected to the input node, and into the external input signal source. The input node voltage is thus equal to the input signal source voltage plus the voltage-drop across the signal input resistor. This input node voltage is compared to an internal reference voltage by a comparator which is also connected to the common input node.

Abstract: A night driving dazzle protection system uses anti-dazzle screening material transmitting less than 40% of incident light and arranged on screened portions of right and left eyeglass regions 30 and 20 in front of a driver's eyes. As viewed by the driver, the eyeglass region 20 in the view of the driver's left eye is screened between about 7:30 o'clock and about 9:00 o'clock, and the corresponding eyeglass region 30 in the view of the driver's right eye is unscreened between about 7:30 o'clock and about 9:00 o'clock. Preferably, right and left eyeglass regions 30 and 20 between about 3:00 o'clock and about 4:30 o'clock are screened for the driver's right eye and unscreened for the driver's left eye. Also, upper portions of each of the eyeglass regions are preferably screened from about 9:00 o'clock to about 3:00 o'clock.

Abstract: A multisource power supply for supplying a plurality of various power levels from a common AC source, including a plurality of switchable power source modules, a power line conditioner PLC including a high voltage switching supply and logic level supply coupled between the AC source and each of the power source modules, a common controller coupled to each of the power source modules for setting and monitoring the output of each of the modules, each of the modules being removable from the multisource power supply, and an interlock control responsive to removal of any of the modules for disabling the high voltage switching supply.

Abstract: A method and apparatus for the internal or blind side sealing of a small local leak (such as a void in casting). The sealing is accomplished by first drilling a hole in the conduit or container where the leak is located and setting a blind side sealer apparatus in the hole. The device consists of a guide that fits loosely into a drilled hole; a slitted metal conical capping means having an outside diameter approximately the same as the drilled hole diameter; a sleeve; and a retractable stem. The slitted cone is filled with a viscous sealant and the slitted cone part of the sealer assembly is pushed through the hole. Once on the other side of the hole, the slitted cone expands enough to prevent it from backing out. When the stem is pulled outward, the slitted cone is forced against the pipe or container wall, spreading the sealant. The stem then snaps at a necked-down position, signaling completion to the operator.

Abstract: Apparatus and method for remotely measuring temperature in which a transmitter having a temperature sensitive element is placed in close proximity with the environment sought to the measured, with the temperature sensitive element controlling a reference voltage applied to a first terminal of a testing circuit, a second terminal of which receives a constant frequency alternating output of an oscillator. The output signal from the testing circuit is a constant frequency signal having a duty cycle which varies with the temperature of the element. An RF signal carrier is modulated at the transition points of the variable duty cycle signal for transmitting bursts of energy which are received and from which a replica signal corresponding to the variable duty cycle signal is reconstructed. A counter in the receiver counts high frequency pulses over a predetermined period of time during "on times" in duty cycle to obtain a numerical indication of the measured temperature.

Abstract: A variable air volume ventilation system (10) is disclosed in which the output air flow from a supply fan (13), delivered through a supply duct (11) to various places within a building, is returned by a return duct (15) through a return fan (17) and then through a connecting duct (18) back to the inlet (20) of the supply fan (13). The static pressure in the supply duct (11) is sensed by a static pressure sensor (40), and the output signal indicative of pressure is used by a variable frequency power supply (44) to provide power to drive the fan motors (36, 37) at a frequency inversely proportional to the difference between the sensed static pressure and a desired static pressure, thereby adjusting the flow through the ventilation system to match demand. Outside make-up air is provided through an outside air duct (50) and is fed into the return duct (15) at a position (52) near the inlet (16) of the return fan (17).

Abstract: A method and apparatus for internally wrapping the surface of a conduit, cylinder or pipeline with a sealing membrane which is adhered to the interior surface. The apparatus applies the membrane in a helical spiral by taking the membrane from a roll and pressing it against the interior surface while applying an adhesive and while transporting the roll longitudinally in the conduit on a transport assembly that rolls internally in the conduit.