Nippon Telegraph and Telephone Corporation

Ntt Innovative Devices Corporation

Ntt Corporation

Nippon Telephone and Telegraph Corporation

Tadashi Minotani

Eri Matsunaga

Masahito Nakamura

Masayuki Tsuda

Kenichi Matsunaga

Mitsuru Shinagawa

Nobutarou Shibata

Masatoshi Tobayashi

Yoshikazu Urabe

Toshiki Kishi

Katsuyuki Ochiai

Aiichirou Sasaki

Kazuo Fujiura

Soichi Oka

Hakaru Kyuragi

Seiji Toyoda

Masahiro Sasaura

Takashi Sawada

Hiroyoshi Togo

Ai-ichiro Sasaki

Nobutaro Shibata

Nobuhiro Toyoda

Ai-Ichiro Sasaki

The transmission interface includes a plurality of transmitters, wherein the transmitters are provided with: a power supply terminal shared by the plurality of transmitters, configured to receive a ground voltage; a bias terminal configured to receive a bias voltage; signal terminals configured to receive a signal voltage; a power supply fluctuation inverting bias unit to which a ground voltage and a bias voltage are applied, and which outputs the ground voltage making its fluctuation 180 degrees out of phase; a modulation unit to which the output of the power supply fluctuation inverting bias unit and a signal voltage are applied, and which outputs the opposite phase ground voltage making its fluctuation in phase; and a laser diode to which the ground voltage and the output of the modulation unit are applied.

Transmission interface and transmitter

An A/D converter includes: a first reference voltage unit that generates a temperature-compensated reference voltage; a second reference voltage unit that generates a second reference voltage calibrated with the reference voltage; an integration unit that generates an integrated voltage obtained by integrating unit voltages using any one of the reference voltage, the second reference voltage, and a ground voltage as an initial value during calibration; a comparator that compares the integrated voltage with a threshold voltage and outputs a determination signal; a calibration control unit that measures an integration time until the integrated voltage exceeds the threshold voltage from the initial value during calibration and calibrates the unit voltages and an offset voltage of the comparator; and a conversion control unit that converts an input voltage into a digital value using a conversion integration time which is the integration time when the input voltage is an initial value and the second reference voltage during conversion.

Self-calibration-function-equipped A/D converter

An embodiment is a connecting circuit connected to the preceding stage of a transmission circuit and configured to receive a baseband signal, includes an isolation element connected between an input terminal and an output terminal, a signal midpoint detection circuit connected parallel to the isolation element, a bias adding circuit connected in series with the signal midpoint detection circuit, and an initial voltage value detection circuit connected to a frame detection circuit. The initial voltage value detection circuit holds an initial voltage value of the baseband signal in accordance with the signal of the frame detection circuit, and outputs the initial voltage value to the signal midpoint detection circuit. The signal midpoint detection circuit detects a midpoint voltage from the baseband signal and the initial voltage value, and outputs the midpoint voltage to the bias adding circuit. The bias adding circuit adds the midpoint voltage to a bias voltage.

Connecting circuit and communication interface

An amplifier circuit includes: an amplifier connected to an isolating element; a signal midpoint detecting circuit connected in parallel with the isolating element; a bias adding circuit connected in series with the signal midpoint detecting circuit; and an initial voltage value detecting circuit connected to the frame detecting circuit. The initial voltage value detecting circuit holds an initial voltage value of the baseband signal using a signal from the frame detecting circuit, and outputs the initial voltage value to the signal midpoint detecting circuit. The signal midpoint detecting circuit detects a midpoint voltage from the baseband signal and the initial voltage value, and outputs the midpoint voltage to the bias adding circuit. The bias adding circuit adds the midpoint voltage to a bias voltage for biasing the baseband signal. The amplifier amplifies the baseband signal.

Amplifier circuit

A looseness detection sensor for detecting looseness of a bolt for fixing a component, including: a resonance unit arranged adjacent to a head portion of the bolt and made of an insulating material confining a high-frequency signal input externally; and a conductive member in conduction with the component across the resonance unit, wherein the conductive member is a cap put on the head portion of the bolt and includes a protrusion contacting a surface of the component.

Looseness detection sensor and method

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.

Looseness detection device and looseness detection method

A bolt tightening torque management structure for a bolt for fastening a component includes: the bolt including a plurality of projections of different heights on a bearing surface of a head; a non-conductive film that is formed on the surface of the component, has a shaft hole through which a shaft of the bolt extends, and has a predetermined size; and a conductive film that has the shaft hole and a plurality of grooves, through which the projections extend, is formed on the non-conductive film, and has the same planar shape as the non-conductive film. The projections other than the projection having the smallest height are configured to be in contact with the surface of the component when the tightening torque of the bolt is appropriate. The base of each projection has a width dimensioned to close the corresponding groove.

Bolt tightening torque management structure and method

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.

Loosening detection structure and loosening detection method using said structure

An AD converter includes: an accumulation conversion unit that performs a comparison of magnitudes of an input voltage Vand an accumulated voltage Vobtained by accumulating a unit voltage and outputs a comparison signal representing a result of the comparison; an accumulation comparison determination unit that repeatedly compares an accumulated voltage V, obtained by repeating the comparison until the comparison signal changes and corresponding to an accumulated voltage Vat which the comparison signal changes, and the input voltage Va predetermined number of times to determine an equivalent-state accumulation number in which a state probability that the comparison signal changes is equal to a threshold; and a control unit that determines conversion data of the input voltage using the equivalent-state accumulation number.

Ad converter

A sensor for detecting looseness of a plurality of bolts and nuts fixing parts includes: a non-conductive film attached to a surface of the part, which is one of the parts, including holes H from which the bolts are inserted; and a conductive film attached to the non-conductive film, configured to receive supply of a high-frequency signal, and having a same planar shape as that of the non-conductive film, wherein the planar shape is a shape in which a resonance frequency of the high-frequency signal confined in the non-conductive film is different according to a position of a loosened bolt, and the planar shape of the conductive film is a shape in which a distance between a bolt and an end portion of the conductive film is different for each of the plurality of bolts.

Looseness detection sensor and how to identify loose bolts

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 are disclosed. An abnormality detection device detects an abnormality of a fixing structure, which includes a conductor and which fix steel plates to each other, and a spacer which includes an insulator and which is disposed between the steel plates and the washer. The abnormality detection device includes 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. The abnormality of the fixing structure is detected by comparing the frequency characteristics with frequency characteristics in a normal state.

Abnormality detection device and fixing structure

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.

Variable reference voltage source

A loosening detection structure used to detect loosening of a bolt includes a material that is disposed between a fixing subject steel plate and a head portion of a metal bolt for fixing the steel plate and either attached to a seating surface of the head portion of the bolt or attached to a washer disposed between the steel plate and the head portion of the bolt, and that has electrical characteristics that vary in response to variation in a force for fastening the bolt to the steel plate.

Loosening detection structure, loosening detection system and method

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.

Transducer, loosening detection system and loosening detection method

An AD converter includes: an integration unit that uses an input voltage as an initial value and repeats an operation of integrating one or both of two types of unit voltages with the input voltage, thereby generating an integrated voltage; a switching threshold voltage unit that includes two types of threshold voltages causing the operation of integrating to be terminated; a comparator that compares the integrated voltage with the threshold voltages; an integration determination unit that, before the operation of integrating is started, causes the comparator to compare the input voltage with a rough adjustment threshold voltage corresponding to a larger one of the unit voltages; a unit voltage switching control unit that, when the rough adjustment threshold voltage is larger than the input voltage, controls the integration unit to generate the integrated voltage by using the two types of unit voltages; and a single unit voltage control unit that, when the rough adjustment threshold voltage is smaller than the input voltage, controls the integration unit to generate the integrated voltage by using only a smaller one of the unit voltages.

Growing community of inventors

Atsugi, Japan

Tadashi Minotani