Abstract: A composite liquid crystal electroluminescent electro-optical display device utilizing single-cell construction. Backlighting is furnished by a low-intensity, low-power-consumption integrally formed electroluminescent light source cooperating with a liquid crystal element with commonly excited electrodes. The integral electro-luminescent light source replaces the requirement for a transflector. The invention offers substantially improved contrast while minimizing physical size, power dissipation and construction complexity.

Abstract: A windshear warning system having an adjustable threshold to avoid triggering nuisance windshear alerts wherein the magnitude and duration of the shear are not sufficient to endanger an aircraft that is flying a landing approach at greater-than-normal approach speed. The present invention provides for variable detection times in either a variable threshold windshear detection or a fixed threshold detection system. A measurement of angle or attack is used to deduce the aircraft's approximate weight from which a normal landing approach speed may be calculated. The difference between the computed landing approach speed and the actual approach speed is used to calculate an add-on differential to the windshear system detection threshold.

Abstract: The electric motor contemplated by this invention includes an armature having two opposed faces mounted on a shaft. The armature is mounted on the shaft intermediate of the ends of the shaft. A pair of commutators are mounted on the shaft adjacent to each of the opposed armature faces. Each of the commutators includes a plurality of commutator bars, each of which has its circumferential width offset relative to the circumferential width of the commutator bars on the other commutator. Alternately or in combinatrion, with the commutator bar offset the brushes in operative engagement with each of the commutators are arranged with their circumferential width offset, relative to the circumferential width of the brushes in operative engagement with the opposite commutator. The electric motor can also be provided with a redundancy capability by a circuit arrangement in which one of the commutators is held as a backup in the event of a failure of the windings of the other commutator.

Abstract: A current source is controlled by the output signal from a digital to analog converter. The output signal from the digital to analog converter is applied to an amplifier unit. The output of the amplifier unit controls current through a pass transistor element, the pass transistor element current being the current applied to the load impedance. A feedback signal is generated by a differential amplifier in response to the current applied to the load impedance. The output signal from the difference amplifier is applied to an input terminal of the digital to analog converter with a polarity resulting in a change in the output signal of the amplifier unit which compensates for any change in the current through the load impedance. A voltage level changing element is included in the pass transistor control terminal to interrupt the current to the load impedance in the event of a degradation in the power supply.

Abstract: The present invention is a technique for forming a signal representing the operator adjustment of a potentiometer. This technique consists of measuring the reference time constant of the resistance between the fixed terminals of the potentiometer and a capacitor, measuring the variable time constant of the resistance of potentiometer between a fixed terminal and the terminal variable by an operator setting and this same capacitor, and again measuring the reference time constant of the resistance between the fixed terminals of the potentiometer and the capacitor. These time constant measurements are made by discharging the capacitor, charging the capacitor through the appropriate terminal of the potentiometer and measuring the time required for the voltage across the capacitor to reach a predetermined threshold level. This measurement sequence is repeated if the two measures of the reference time constant differ by more than a predetermined amount.

Abstract: The present invention is a technique for forming a digital signal representing an environmental condition. The technique consists of measuring the variable time constant of an analog sensing device having a variable resistance dependent upon the environmental condition and a capacitor as well as measuring the reference time constant of a precision fixed resistor and the same capacitor. The time constants are measured by discharging the capacitor, charging the capacitor through the appropriate element and measuring the time for the voltage across the capacitor to reach a predetermined level. Lastly, the digital ratio between the two time constants is formed. This digital ratio is the digital representation of the environmental condition sensed by said analog sensing device.

Abstract: The present invention is a technique for operator entry of a time program into a programmable device. An operator adjustable input device having associated time indicia is employed to enter a time signal indicative of a time a selected time. A manual control state input device enables selection of one a control state. When the programmable device is in a program mode the selected control state is stored in a program memory at a location corresponding to the selected time. This program memory stores a program of control states for particular times. When in a control mode a clock signal indicative of the current time permits recall of the control state for the current time, thus permitting control in accordance with the recalled control state. In accordance with the preferred embodiment the programmable device is an electronic thermostat.

Abstract: A control device for energization of a load employs a bidirection triggerable solid state switching device connected in series with an alternating current power source and the load. In order to prevent the passage of excessive, potentially destructive currents through the switch if the load is shorted out, the microprocessor which controls the energization of the switch senses the time required for the voltage across the switch to attain a predetermined value. If the load is shorted the potential difference across the switch increases and attains the predetermined value a shorter time after zero-crossing of the alternating current. When this occurs more than a predetermined number of consecutive times, the generation of triggering pulses for the solid state switch is inhibited for a predetermined time. In the preferred embodiment the control device is a thermostat for controlling a temperature modifying load such as a furnace or air conditioner.

Abstract: The present invention is a method for specifying a constant in a digital electronic system. This technique employs the ratio of resistances between a reference resistor and a constant specifying resistor. The time constant of the constant specifying resistor and a capacitor is measured by discharging the capacitor, charging the capacitor through the constant specifying resistor and counting the number of predetermined time intervals required for the voltage across the capacitor to reach a predetermined threshold voltage. A similar time constant measurement is made for the reference resistor and the capacitor. The same conditions are employed as far as possible during these two measurements to insure the only differences are in the value of the resistances. The externally specified constant is computed from the digital ratio of the time constant of the constant specifying resistor and the time constant of the reference resistor.

Abstract: The microwave frequency characteristics of a cavity having a center conducting element and conducting cavity are modified by changing the length of the center conducting element. The resonating structure is comprised of a coaxial member providing the principal resonating surfaces. One end of the coaxial member is coupled to a wall of the cavity surrounding the center conducting member with provision for access to the interior of the center conducting member from a position exterior to the cavity. The second end of the center conducting element is free. In addition, the second end of the resonating element has threads fabricated on an interior surface and a self-locking insert positioned in the threaded portion. A threaded rod is inserted through the self-locking insert and extends beyond the center conducting element into the cavity.