Hamamatsu-photonics K.k.

Hamamatsu Photonics Kabushiki Kaisha

Suzuki Motor Corporation

Other

Takuya Nakamura

Shinichiro Aoshima

Yutaka Tsuchiya

Hironori Takahashi

Tsuneyuki Urakami

Isuke Hirano

All terrain vehicle

Motor scooter

Power assisted bicycle

A trigger circuit is composed of a frequency multiplying portion which receives an electric signal to be measured and multiplies its repetitive frequency so as to output a multiple signal, a comparing portion which receives this multiple signal and outputs a square wave signal corresponding to its value, and a dividing portion which divides the square wave signal so as to output a trigger signal. Accordingly, even when a noise component is superposed on the electric signal to be measured, a trigger signal having little jitter and a repetitive frequency lower than that of the electric signal to be measured is output. Also, the electric field measuring apparatus in accordance with the present invention comprises this trigger circuit and measures, with a highly accurate timing, the electric field of the object to be measured.

Low jitter trigger circuit for electro-optic probing apparatus

This invention has as its object to provide a voltage measurement apparatus which has a compact probe unit, and which can perform a measurement in a non-contact manner. The voltage measurement apparatus includes detection means for detecting an electric field generated in a space by a voltage applied to the surface of a device to be measured, light-emitting means for modulating output light by superposing a detected signal obtained from the detection means on a bias current which is supplied to inductively radiate the output light, a constant current source for supplying the bias current to the light-emitting means, extraction means for extracting a signal component of the output light from the light-emitting means, and light-transmission means for guiding the output light from the light-emitting means to the extraction means, and measures the applied voltage to the surface of the device to be measured by bringing the detection means close to the device to be measured in a non-contact manner.

Voltage detection apparatus

A light source for emitting a pulsed laser beam having an ultrashort pulse width and a voltage detector including the light source therein. The light source includes a laser driving unit for driving the laser source to output the pulsed laser beam while the intensity of the pulsed laser beam is stabilized. A chirp compensator is also included to compensate for a chirp in the pulsed laser beam. A wavelength selector is used to extract light having a desired wavelength from the pulsed laser beam, thereby obtaining a pulsed laser beam having an ultrashort pulse width and a desired narrow spectral band width.

Voltage detection apparatus using short pulse light source with narrow

A low noise pulsed light source utilizing a laser diode for generating a short pulsed light of a high repetitive frequency. The low noise pulsed light source includes a laser diode drived by an electric pulse generator for emitting repetitive pulsed light; a current source for supplying a bias current to the laser diode; and a photodetector for detecting the repetitive pulsed light emitted from the laser diode; and control means. The control means modulates at least one of the bias current from the current source and the amplitude of a pulse signal generated from the electric pulse generator in accordance with an output signal from the photodetector such that the intensity of the pulsed light is kept unchanged and any noise involved in the same is reduce. A feedback system including the photodetector and the control means has a peak in its frequency characteristics within a frequency band for light detecting in a light measuring system utilizing the low noise pulsed light source.

Low noise pulsed light source utilizing laser diode and voltage detector

A voltage detecting device using an electro-optical material with a refractive index which is changed by a voltage at a part of an object comprising a light source, comprises an electro-optical material for changing the optical path of the light beam from the light source in accordance with the refraction index of the electro-optical material and a slit or optical fiber extractor at a predetermined position at the output of the electro-optical material for extracting the quantity of light of the light beam at the predetermined position and a detector detecting a voltage at the part of the object from the quantity of light extracted.

Voltage detecting device

A low noise pulsed light source using a laser diode for generating a short pulsed light of a high repetitive frequency. The low noise pulsed light source includes a laser diode drived by an electric pulse generator for emitting repetitive pulsed light; a current source for supplying a bias current to the laser diode; and a photodetector for detecting the repetitive pulsed light emitted from the laser diode; and control means. The control means modulates at least one of the bias current from the current source and the amplitude of a pulse signal generated from the electric pulse generator in accordance with an output signal from the photodetector such that the intensity of the pulsed light is kept unchanged and any noise involved in the same is reduced.

Low noise pulsed light source using laser diode

A first part of input light containing both background light and signal light is extracted by a sampling streak tube and converted to a first electric signal by a photodetector. A second part of the input light containing only background light is extracted by the same sampling streak tube by offsetting the sampling timing and converted to a second electric signal by the photodetector. A signal component corresponding to the signal light is extracted by taking the difference between the first and second electric signals. In one embodiment, the sampling timing is offset by applying a chopping voltage to chopping electrodes provided in the sampling streak tube.

Optical signal detector incorporating means for eluminating background

A voltage detector for measuring the voltage waveform of an object being measured on the basis of the optical intensity signal corresponding to the voltage of the object, including a light source for generating light, an optical modulator for converting the light from the light source into an optical intensity signal corresponding to the voltage of the object, and a sampling type high-speed photodetector for sampling the optical intensity signal from the optical modulator and measuring the voltage waveform of the object on the basis of the sampled optical intensity signal.

Voltage detector using a sampling type high-speed photodetector

A voltage detecting device using an electro-optical material with a refractive index that is changed by a voltage at a part of an object comprising a light source, an electro-optical material for changing the optical path of the light beam from the light source in accordance with the refractive index of the electro-optical material, and a streak camera to display on a Phosphor screen an image of the voltage over time at a part of the object.

A voltage detector comprises a pulse light source, a delay means, a dispersing prism made of an electro-optic material and a linear image sensor. The electro-optic material senses a voltage developing in a selected area of an object as a change of its refractive index. An optical path of a pulse light is changed by the dispersing prism according to the change of its refractive index. An output pulse light emerging from the dispersing prism is detected by a linear image sensor. A waveform of the periodic voltage pulses can be detected by gradually delaying a phase of the pulse light emitted from the light source. The voltage developing in one-dimensional positions in the object can be also detected by employing a dispersing prism extending along the positions to be detected and a two-dimensional detector.

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Hamamatsu, Japan

Takuya Nakamura