Abstract: A system including a respiration detection device configured to detect respiration of an individual within a defined environment regardless of a position of the individual within the defined environment wherein detection is performed at a location unobstructed by a physical barrier within the defined environment, a processor with non-transitory computer readable medium configured to evaluate respiration data from the respiration detection device to determine the individual based on a location of the individual within the defined environment and a notification device to provide notification when the individual is detected in the defined environment after at least one of a defined time period and a reduction in respiration. A method is also disclosed.

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 of the windings in a transformer or other electrical apparatus.

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 of the conductor in a buried, undersea or submerged electrical power cable.

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 of the conductor in a buried, undersea or submerged electrical power cable.

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 of the windings in a transformer or other electrical apparatus.

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 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 variable attenuation signal acquisition probing system and voltage measurement system uses an optical cavity to acquire a signal under test. The probing system has an optical transmitter and receiver that are coupled to the optical cavity via an optical transmission system. The optical cavity has an electrode structure having apertures formed in the optical cavity that are parallel to propagation path of the optical signal within the cavity. A modulated optical signal is generated by the optical cavity in response to the signal under test creating an electro-magnetic field distribution in electro-optic material in the optical cavity that overlaps the optical path of the optical signal propagating in the optical cavity which varies the index of refraction of electro-optic material in the optical path. Changes in the polarization state of the optical signal attenuates the magnitude of the output electrical signal of the optical receiver.

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 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 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: An optical cavity having an electro-optic material disposed between opposing optically reflective material has an electrode structure with first and second apertures disposed generally parallel to an optical signal propagating within the electro-optic material. Electrically conductive material is disposed within the apertures coupling an electrical signal to the optical cavity.

Abstract: A signal acquisition probing system uses a micro-cavity laser to acquire an electrical signal from a device under test. The micro-cavity laser has a VCSEL gain medium and an electro-optic optical resonant cavity. The micro-cavity laser is pumped by an external laser source and generates a frequency modulated optical signal derived from the device under test electrical signal creating an electro-magnetic field distribution in electro-optic material in the micro-cavity laser that overlaps the optical path of the optical signal propagating in the electro-optic material. The frequency modulated optical signal is coupled to an optical receiver which converts the frequency modulated optical signal to an electrical signal. The electrical signal is coupled to measurement test instrument for processing and displaying of the electrical signal.

Abstract: A signal acquisition probing system uses a micro-cavity laser to acquire an electrical signal from a device under test. The micro-cavity laser has VCSEL gain mediums and an electro-optic optical resonant cavity. The micro-cavity laser is pumped by an external laser source and generates polarized frequency modulated optical signals derived from the device under test electrical signal creating an electro-magnetic field distribution in electro-optic material in the micro-cavity laser that overlaps the optical path of the polarized optical signals propagating in the electro-optic material. The polarized frequency modulated optical signals are coupled to an optical receiver which converts the polarized frequency modulated optical signals to an electrical signal. The electrical signal is coupled to measurement test instrument for processing and displaying of the electrical signal.

Abstract: A signal acquisition probing system uses an optical cavity to acquire a signal under test. The probing system has an optical transmitter and receiver that are coupled to the optical cavity via an optical transmission system. The optical cavity has an electrode structure having apertures formed in the optical cavity that are parallel to propagation path of the optical signal within the cavity. A modulated optical signal is generated by the optical cavity in response to the signal under test creating an electro-magnetic field distribution in electro-optic material in the optical cavity that overlaps the optical path of the optical signal propagating in the optical cavity which varies the index of refraction of electro-optic material in the optical path. The signal acquisition probing system is connected to a measurement instrument to form a voltage measurement system.

Abstract: An electrode structure for electro-optic material used in optical cavities is described. The electrode structure has first and second apertures disposed generally parallel to an optical signal propagating within the electro-optic material. Electrically conductive material is disposed within the apertures coupling an electrical signal to the electro-optic material.

Abstract: A variable attenuation signal acquisition probing system and voltage measurement system uses an optical cavity to acquire a signal under test. The probing system has an optical transmitter and receiver that are coupled to the optical cavity via an optical transmission system. The optical cavity has an electrode structure having apertures formed in the optical cavity that are parallel to propagation path of the optical signal within the cavity. A modulated optical signal is generated by the optical cavity in response to the signal under test creating an electromagnetic field distribution in electro-optic material in the optical cavity that overlaps the optical path of the optical signal propagating in the optical cavity which varies the index of refraction of electro-optic material in the optical path. Changes in the polarization state of the optical signal attenuates the magnitude of the output electrical signal of the optical receiver.

Abstract: An optically pumped micro-cavity laser has an optical gain cavity and an optical resonant cavity. The optical gain cavity has a gain medium disposed that generates an optical output in response to an optical pump signal. The optical resonant cavity has an electro-optic material in which is disposed an electrode structure with first and second apertures disposed generally parallel to an optical signal propagating within the electro-optic material. Electrically conductive material is disposed within the apertures coupling an electrical signal to the optical cavity.

Abstract: An acoustic damping material for electro-optic material has an adhesive material combined with a ceramic crystalline material such that the acoustic impedance of the combined adhesive material and the ceramic crystalline material is substantially the same as the acoustic impedance of the electro-optic material.

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.