Abstract: A method is disclosed that combines optical ranging with infrared spectroscopy to provide multi-dimensional physical shape and spectral signatures of room occupancy in near real time. The disclosed approach creates a near real-time spatial map of indoor CO2 concentrations and temporal gradients that, when combined with spatial mapping of the room, can give a reliable method of detecting room occupancy and occupancy count. With multi-sweep integration, the average CO2 concentration in the room can also be determined.

Abstract: A current transducer is disclosed that is capable of measuring DC or AC currents in a conductor. The transducer housing has one or more slots into which a conductor is located. The current transducer maintains accuracy independent of the conductor position.

Abstract: A thermometer and extensometer for cables and conductors is described. The travel time of one or more acoustic signals along a conductor is used to determine the temperature along the conductor and the length of the conductor. The acoustic frequency is selected to minimize temporal dispersion of the propagating acoustic energy. The technique can be used to measure the temperature and sag of an overhead power line, the temperature of the windings in a transformer, or the temperature of the central conductor in a coaxial power cable.

Abstract: A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference electrical current carried by a conductor positioned within the sensing window of the current sensor is used to correct variations in the output signal due to temperature variations and aging.

Abstract: A modular, low weight impedance dropping power supply with battery backup is disclosed that can be connected to a high voltage AC source and provide electrical power at a lower voltage. The design can be scaled over a wide range of input voltages and over a wide range of output voltages and delivered power.

Abstract: A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference magnetic field generated within the current sensor housing is detected by the magnetic field sensors and is used to correct variations in the output signal due to temperature variations and aging.

Abstract: A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference magnetic field generated within the current sensor housing is detected by a separate but identical magnetic field sensor and is used to correct variations in the output signal due to temperature variations and aging.

Abstract: A method is described to provide temperature compensation and reduction of drift due to aging for a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. The offset voltage signal generated by each magnetic field sensor is used to correct variations in the output signal due to temperature variations and aging.

Abstract: A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

Abstract: A voltage sensor is described that consists of a plurality of identical series-connected sections, where each section is comprised of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. The voltage sensor can be scaled to various voltage levels by varying the number of series-connected sections.

Abstract: A voltage sensor is described that consists of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. Also disclosed is a material with a large and stable dielectric constant. The dielectric constant can be tailored to vary with position or direction in the material.

Abstract: A voltage sensor for measuring the voltage on high voltage lines is formed by an electrically isolating-section of material with resistive shielding (RS) that structures the electric field generated by a voltage difference between the two ends of the isolating-section and provides shielding of the internal electric field from sources of electric field interference external to the voltage sensor. At least one electric field sensor is provided to sense the electric field in the isolating-section the output(s) of which is(are) used to infer the voltage difference.

Abstract: An electro optical circuit for transmitting an information bearing signal, such as a signal in the RF, AF or microwave frequency domains, to a predetermined location includes a laser for generating coherent light to be used as a carrier, and an electro optical modulator for receiving the information signal and the coherent light and generating first and second modulated light signals which respectively comprise the coherent light modulated by the information signal and the coherent light modulated by the inversion of the information signal. The first and second modulated light signals are supplied to a detector at the predetermined location through separate optical paths.