Abstract: A self-calibration-function-equipped AD converter that does not require a measurement device for calibration includes: a control unit including a calibration control unit configured to control an operation of calibrating the self-calibration-function-equipped AD converter, and a conversion control unit configured to control an operation of converting an input voltage to be subjected to conversion into a digital signal; a reference voltage unit configured to output a reference voltage; and an integration/conversion unit including an integrating unit configured to generate an integration voltage obtained by integrating two or more types of unit voltages, a comparator that has two inputs and is configured to compare the integration voltage and the input voltage or the reference voltage, and a crossbar switch configured to switch a connection depending on whether the integration voltage is to be input to one input of the comparator and the input voltage or the reference voltage is to be input to another input, or

Abstract: A crack detection device includes: a sensor unit that has a three-layer structure of conductor-insulator-conductor and is attached to a structure; a frequency characteristics acquisition unit that sweeps a predetermined frequency range to acquire a plurality of frequencies at which the impedance of the sensor unit is maximum or minimum; a crack presence/absence determination unit that determines the presence or absence of a crack based on a nonuniformity of the plurality of frequencies; a crack position table in which a relationship between crack positions and frequency shift directions is recorded; and a crack position detection unit that, when the crack presence/absence determination unit determines that there is a crack, takes a difference between two frequencies acquired by the frequency characteristics acquisition unit to determine a sign, and then refers to the crack position table in accordance with the sign to detect a crack position.

Abstract: A transducer includes a conductive sheet installed on a sheath of a cable, an insulative sheet installed on the conductive sheet, holes being formed in predetermined positions of the insulative sheet, and a conductive sheet installed on the insulative sheet, holes being formed in predetermined positions of the conductive sheet. The transducer has structure in which, when the cable is tightened by the screw from the top of the conductive sheet and fixed, the distal end of the screw comes into contact with the conductive sheet passing through the holes formed in the insulative sheet and the conductive sheet, and the conductive sheet and the conductive sheet are electrically connected.

Abstract: A loosening detection device according to the present embodiment includes multiple washers having holes that allow bolts to pass therethrough, and including metals insulated from each other, a transmission line that electrically connects between the metals and between the metals of the washers, and a transmission line that includes a terminal pair at one end thereof, and that has the other end electrically connected to the metals of the washer. A resonance frequency is measured from the terminal pair to detect loosening of the bolts on the basis of a change in the resonance frequency.

Abstract: A variable reference voltage source that generates a variable reference voltage corresponding to setting data set from outside includes a control unit including a calibration control unit that controls operation for acquiring calibration data including calibration values of an offset voltage and a predetermined unit voltage of a determiner, which determines magnitudes of two voltages, and an output control unit that controls operation for generating, based on the calibration data, a variable reference voltage corresponding to the setting data set from the outside, a reference voltage unit that outputs a reference voltage, and an integrated-voltage generating unit that repeats, when the calibration control unit controls the operation, an integrating operation until an integrated voltage obtained by integrating at least two or more kinds of unit voltages becomes equal to the reference voltage and outputs, when the output control unit controls the operation, the variable reference voltage corresponding to the se

Abstract: A looseness detection structure includes: a structure (transducer) T which is formed on a surface of a cable; a screw which tightens and fixes the cable in contact with the structure T; and a terminal (detection unit) which transmits a transmission signal to the structure T, receives a reception signal returning after propagating through the structure T, and detects the loosening of the screw based on a change in the reception signal.

Abstract: An AD converter is provided with a control unit including a calibration control unit that controls an operation for calibrating the control unit and a conversion control unit that controls an operation for converting a target input voltage into a digital signal; a reference voltage unit that outputs a reference voltage; and an integrating converter unit including an integrating unit that generates an integrated voltage by integrating a predetermined unit voltage, a comparator that has two inputs and compares the integrated voltage and an input voltage or a reference voltage Vref, and a crossbar switch that switches connections between the case where the integrated voltage is inputted to one of the inputs of the comparator and the input voltage or the reference voltage Vref is inputted to the other input and the case where the input voltage or the reference voltage Vref is inputted to one of the inputs of the comparator and the integrated voltage is inputted to the other input.

Abstract: Provided are a crack detection system and a crack detection method that distinguish between a case where a crack is generated in a structure and other cases not to bring about erroneous detection. In a sensor terminal that detects, from a crack generated in a transducer provided on a structure, a crack in the structure, the transducer having a three-layered structure of conductor-insulator-conductor, the crack detection system including: an impedance measurement unit that measures impedance between the two conductors of the transducer; and a crack detection processing unit that calculates, from a frequency characteristic of the impedance, periodicity data regarding periodicity of a frequency at which impedance becomes a peak, and detects a presence of a crack in the structure in a case of periodicity data different from initially-measured periodicity data being included.

Abstract: An AD converter is provided with a control unit including a calibration control unit that controls an operation for calibrating the control unit and a conversion control unit that controls an operation for converting a target input voltage into a digital signal; a reference voltage unit that outputs a reference voltage; and an integrating converter unit including an integrating unit that generates an integrated voltage by integrating a predetermined unit voltage, a comparator that has two inputs and compares the integrated voltage and an input voltage or a reference voltage Vref, and a crossbar switch that switches connections between the case where the integrated voltage is inputted to one of the inputs of the comparator and the input voltage or the reference voltage Vref is inputted to the other input and the case where the input voltage or the reference voltage Vref is inputted to one of the inputs of the comparator and the integrated voltage is inputted to the other input.

Abstract: There is provided an abnormality detection device and a fixing structure which are suitable for detecting an abnormality of a fastener such as a bolt or a nut. An abnormality detection device detects an abnormality of a fixing structure including a bolt, a nut, and a washer which include a conductor and fix steel plates to each other, and a spacer which includes an insulator and is disposed between the steel plates and the washer, the abnormality detection device including: a transmission antenna that radiates electromagnetic waves to the fixing structure; a reception antenna that receives electromagnetic waves reflected by the fixing structure; and an abnormality detector that changes a frequency of the electromagnetic waves radiated from the transmission antenna to acquire frequency characteristics of standing waves received by the reception antenna and detects an abnormality of the fixing structure by comparing the frequency characteristics with frequency characteristics in a normal state.

Abstract: To provide a variable reference voltage source for which a measuring instrument is unnecessary for calibration on the outside. A variable reference voltage source that generates a variable reference voltage corresponding to setting data set from outside includes a control unit including a calibration control unit that controls operation for calibrating an offset and a predetermined unit voltage inside the variable reference voltage source and an output control unit that controls operation for outputting the variable reference voltage, a reference voltage unit that outputs a reference voltage Vref, and an integrated-voltage generating unit that repeats, when the calibration control unit controls the operation, an integrating operation until an integrated voltage obtained by integrating the predetermined unit voltage becomes equal to the reference voltage Vref and outputs, when the output control unit controls the operation, the variable reference voltage corresponding to the setting data.

Abstract: Provided is a surface change detection body capable of detecting a change in the surface of an object only with passive components.

Abstract: A looseness detection structure configured to detect looseness between a bolt and a nut that fix two components including a conductive film configured to be attached on a surface of the component, the surface of the component including a hole into which the bolt is inserted, the conductive film being attached such that the conductive film is not directly conductive to the component, a part of the conductive film having a dimension relating to a half wavelength of a high-frequency signal propagating inside the components, and a non-conductive film between a surface of the component and the conductive film in a case where surfaces of the components are conductors, and a second conductive film on a surface of the component in a case where the surfaces of the components are insulators, the second conductive film being opposite to the conductive film.

Abstract: A crack detection device includes: a sensor unit that has a three-layer structure of conductor-insulator-conductor and is attached to a structure; a frequency characteristics acquisition unit that sweeps a predetermined frequency range to acquire a plurality of frequencies at which the impedance of the sensor unit is maximum or minimum; a crack presence/absence determination unit that determines the presence or absence of a crack based on a nonuniformity of the plurality of frequencies; a crack position table in which a relationship between crack positions and frequency shift directions is recorded; and a crack position detection unit that, when the crack presence/absence determination unit determines that there is a crack, takes a difference between two frequencies acquired by the frequency characteristics acquisition unit to determine a sign, and then refers to the crack position table in accordance with the sign to detect a crack position.

Abstract: Provided are a crack detection system and a crack detection method that distinguish between a case where a crack is generated in a structure and other cases not to bring about erroneous detection. In a sensor terminal that detects, from a crack generated in a transducer provided on a structure, a crack in the structure, the transducer having a three-layered structure of conductor-insulator-conductor, the crack detection system including: an impedance measurement unit that measures impedance between the two conductors of the transducer; and a crack detection processing unit that calculates, from a frequency characteristic of the impedance, periodicity data regarding periodicity of a frequency at which impedance becomes a peak, and detects a presence of a crack in the structure in a case of periodicity data different from initially-measured periodicity data being included.

Abstract: When a human hand (100) holds a transceiver (3a), the hand holds a bottom of an external wall surface and a side of the external wall surface of an insulating case (33). Therefore, a transmitting and receiving electrode (105) and an insulating film (107) cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulating case (33). A first ground electrode (131), a second ground electrode (161), and a third ground electrode (163) are attached to upper portions of the internal wall surface of the insulating case (33) apart from the transmitting and receiving electrode (105). An insulating foam member (7a) is interposed between the insulating case (33) and a transceiver main body (30), and an insulating foam member (7b) is interposed between the transceiver main body (30) and a battery (6).

Abstract: The present invention relates to an electric field sensor including: a light source (1); an electro optic crystal (7) which is applied with an electric field based on a signal under test, in which a birefringent index changes according to the electric field, and which changes a polarization state of light incident from the light source according to the birefringent index and emits the light; and a detector (9, 17, 19, 21) that detects an electric signal according to the change of the polarization state of the light emitted from the electro optic crystal (7). Further, the electric field sensor includes: a signal electrode (11) for applying the electric field based on the signal under test to the electro optic crystal (7); a counter electrode (12) that forms a pair with the signal electrode (11); and an auxiliary electrode (61) that is electrically connected to the counter electrode (12), and that forms a capacitance with ground.

Abstract: A transmitter (2) modulates information to be transmitted with an alternating-current signal having a predetermined frequency and includes a variable reactance section (16) which produces resonance with a stray capacitance (18) between a circuit ground (17) in the transmitter (2) and an earth ground (20) which strays from the earth ground (20) and a stray capacitance (19) between the human body (3) and the earth ground (20).

Abstract: A reactance adjuster includes an electrode (123) inducing an electric-field in an electric-field transmittable medium (121), an adjusting signal generation section (13) outputting alternatingly a high level or a low level signal to a resonance section (7), an electric-field detection section (15) generating an electric signal based on the electric-field in the medium (121), a first electric-charge storing means (C1) storing electric-charge according to the electric signal when the section (13) outputs a high level signal, a second electric-charge storing means (C2) storing electric-charge according to the electric signal when the section (13) outputs a low level signal, a voltage comparator (10) outputting a predetermined signal based on a voltage difference between the storing means, a control section (19) outputting a constant voltage when the first and the second storing means (C1, C2) are storing electric-charge and a voltage based on a predetermined signal when the storing ends.

Abstract: There is provided a transmission means (3) configured to transmit a modulated signal obtained by modulating data, a transmission electrode (8) that induces an electric field based on the modulated signal in an electric field transmission medium (20), a first reactance means (2) that is provided between the electric field transmission medium (20) and an earth ground (14) and configured to cause resonance with parasitic capacitance produced between a ground (6) the transmission means (3) and the earth ground (14), parasitic capacitance produced between the electric field transmission medium (20) and the ground (6) of the transmission means (3) and parasitic capacitance produced between the electric field transmission medium (20) and the earth ground (14), and a second reactance means (1) provided between an output of the transmission means (3) and the ground (6) of the transmission means (3) or between the transmission electrode (8) and the ground (6) of the transmission means (3).