Ando Electric Company

Other

Nippon Telegraph and Telephone Corporation

Yokogawa Electric Corporation

The Kansai Electric Power Co., Inc.

Nobuaki Takeuchi

Yoshiki Yanagisawa

Mitsuru Shinagawa

Tadao Nagatsuma

Jun Kikuchi

Yoshio Endou

Junzo Yamada

Nobukazu Banjo

Kazuyoshi Matsuhiro

Takao Minami

Koichi Shinozaki

Takamu Genji

Naoyuki Nozaki

Shoji Adachi

Ryoji Handa

Takayuki Sugizaki

Chitomi Terayama

Nobukazu Banjou

Keiichi Shimizu

An optical fiber temperature distribution measuring device includes: an optical fiber as a sensor; a calculation control unit for measuring a temperature distribution along the optical fiber based on an intensity ratio between Stokes light and anti-Stokes light of backward Raman scattered light from the optical fiber; and a temperature correction unit for correcting the temperature distribution by using temperature dependence of a loss difference between the Stokes light and the anti-Stokes light.

Optical fiber temperature distribution measuring device

The invention provides a structure that does not employ complicated and large-scale control circuits or control memory, minimizes the circuits for real time processing, and allows the use of refresh memory. The invention provides a test clock ( - ) comprising a data processing apparatus ( - ) provided for each electrode pin of the measured device ( ), a memory ( - ) that carries out reading and writing of the test pattern data and the like, a first-in-first-out element ( - ) that executes queue processing of the data read out from the memory, a delay circuit ( - ) that delays the output signal of the first-in-first-out element, and a measured device driver ( - ) that inputs into the electrode pin the output signal of the delay circuit, and in which the data processing apparatus ( - ) of adjacent test blocks are connected into a loop via the input-output circuit ( - ).

Semiconductor test apparatus

An electro-optic sampling apparatus is provided to enable measurement on potentials of signals on the conductor of coaxial cable with high precision and with ease. Herein, an electric input connector inputs a measured electric signal, which is introduced to a conductive path such as a microstrip line. An electro-optic material (e.g., Bi SiO ) that provides electro-optic effect such as Pockel's effect is fixed to a bare portion of the conductive path and is varied in birefringence ratio in response to strength of electric field caused by the conductive path through which the measured electric signal transmits. The conductive path is then terminated by a terminal device. Now, a laser beam is radiated toward the electro-optic material, wherein it is varied in polarization in response to variations of the birefringence ratio. Then, the laser beam is reflected by a dielectric mirror and is separated into two beams by a polarization beam splitter. Photodiodes are provided to convert the two beams to electric signals representing potentials. Thus, the apparatus measures voltage of the measured electric signal based on the electric signals.

Electro-optic apparatus for measuring signal potentials

The present invention allows reducing the power consumption, reducing the amount of heat generation, improving the frequency characteristics, and reducing noise superposition. A control circuit supplies to a control circuit a control signal CS that indicates the setting voltage of a DUT as a control signal CS . In addition, the control circuit controls switching power sources and and the polarity control circuits and depending on control signals CS to CS such that the voltage drop amount of the control elements and becomes a value sufficient to operate the control elements and based on a control signal CS and a detected signal DS that is fed back from the DUT . The control circuit controls the control elements and depending on the control signal CS . The control elements and generate a voltage that is to be output to the DUT from the output voltage generated by the switching power sources and and whose polarity is controlled by the polarity control circuits and

Semiconductor test apparatus with reduced power consumption and heat generation

An electro-optic sampling oscilloscope (or EOS oscilloscope) uses an electro-optic probe containing an electro-optic crystal, which is placed under effect of an electric field caused by a measured signal. Laser pulses are supplied to the electro-optic crystal wherein they are subjected to polarization. Then, measurement data representative of a waveform of the measured signal are produced in response to polarization states of the laser pulses and are stored in a measurement data storage. A user can select specific measurement data by using a list of files of multiple measurement data which is displayed on a screen. Then, the EOS oscilloscope displays an outline waveform which is created based on a reduced number of sample points extracted from the selected measurement data. Comments and/or measurement conditions can be stored in the measurement data storage in relation to the measurement data, so that they are adequately displayed on the screen.

Electro-optic sampling oscilloscope

A semiconductor testing apparatus capable of displaying its measurement results in an easily understandable manner is provided. The apparatus comprises a display section for displaying a measurement result of a change in time of a voltage distribution on a measurement plane of a measured device and an input section for entering parameters for the display of the measurement result. When a measurement time is entered as a parameter, the display section displays the measurement result by means of a three-dimensional graph and a representation in numerals, letters or symbols of the measurement time. The graph shows along its three axes a first coordinate in a first direction on the measurement plane, a second coordinate in a second direction which is perpendicular to the first direction, and a voltage at the measurement time at a position on the measurement plane defined by the first and second coordinates.

Semiconductor testing apparatus

A multi-branch optical network testing method (or device) is provided to perform a fault isolation test on an optical network that branches off at a branch point by a number of optical lines having terminal ends respectively. Herein, optical pulses are input to the optical network, from which they are returned as reflection beams. Then, response beams corresponding to mixture of the reflection beams are converted to OTDR waveform data representing a waveform whose optical power gradually decreases in accordance with a distance from an OTDR measurement device and which has a number of reflection peaks. The OTDR waveform data are subjected to logarithmic conversion to produce logarithmic waveform data representing a logarithmic waveform. An approximation method of least squares is effected on the logarithmic waveform data to produce an approximation line, which crosses the logarithmic waveform at points of intersection corresponding to Fresnel reflection points. Using the Fresnel reflection points as split points to split the OTDR waveform data into a number of ranges. Attenuation constants are repeatedly calculated with respect to each of the ranges every measurement time and are stored in a storage device. Thereafter, fault determination is automatically performed based on the attenuation constants stored in the storage device with respect to the fault occurrence time, fault occurrence line and fault occurrence distance.

Device and method for testing of multi-branch optical network

Pins of an integrated circuit are provided with timing axis signals for testing in the time axis without discrepancies. An electro-optic probe in proximity to a plurality of contact points of a device under test uses positions of equal distance or a pre-set distance as skew measurement points, and detects timing axis signals on each microstrip line, A phase detector detects the phase of the timing axis signals that the electro-optic probe detects, and a phase difference calculator finds the phase difference between the phase detected by the phase detector and a reference value. Phase control of the timing axis signals is carried out by a phase controller so as to cancel the obtained phase difference.

Integrated circuit tester

In the present invention, measuring the one-dimensional or two-dimensional voltage distribution or electrical field distribution in a measured device is made possible, and a reduction in the measuring time can be implemented. The present invention comprises a first optical system ( ) wherein light emitted from the light source is shaped into a line-shaped light beam and irradiates a desired measurement line in the measured device via the electrooptic element, a second optical system ( ) that maintains as-is the shape of the line-shaped light beam reflected from the desired measurement line in the measured device after transiting the electro-optic element, a light receiving device ( ) that receives the line-shaped light beam emitted from the second optical system and converts each of the measured points to an electrical signal depending on the strength of each light beam reflected at each of the measured points on the desired measurement line on the measured device and outputs the result, and a signal processing device ( ) that calculates the voltage or electrical field at each of the measured points of the measured device from the output signal of the light receiving device and calculates the electrical field distribution or the voltage distribution at the measured part of measured device.

The apparatus for inspecting integrated circuits according to the present invention comprises: a test signal generating device that outputs an optical test signal; an optical distributor that distributes the optical test signal into a plurality of distributed optical signals by transmitting the optical test signal through a branching optical fiber network; and a plurality of pin cards each of which generates an electric test signal by performing phase adjustment of each distributed optical signal. The pin cards are arranged so as to apply the electrical test signals to pins of an integrated circuit to be inspected.

Apparatus for inspecting integrated circuits

In a light receiving circuit for use in electro-optic sampling oscilloscope which receives first and second optical, photodiodes and are connected in series between a positive bias power supply P and a negative bias power supply N. The photodiodes and receive optical signals whose polarization state correspond to the voltage of a signal to be measured and convert the thus-received optical signals into electric signals. An amplifier amplifies an electric current appearing in a point of connection P between the photodiodes and A current monitor detects the electric signal converted by the photodiode and a current monitor detects the electric signal converted by the photodiode The electric signal detected by the current monitor is subjected to analog-to-digital conversion by an analog-to-digital converter and the electric signal detected by the current monitor is subjected to analog-to-digital conversion by an analog-to-digital converter A control section formed from a subtraction circuit controls a ratio of polarization between the optical signals such that the difference between the value of the current detected by the current monitor and the value of the current detected by the current monitor becomes smaller.

Light receiving circuit for use in electro-optic sampling oscilloscope

The present invention relates to an electro-optic sampling oscilloscope. The delay circuit in the electro-optic sampling oscilloscope comprises a delay time detecting circuit, a regulation time determining circuit, a counter circuit and a delay regulating circuit. The delay time detecting circuit detects in the trigger signal a value corresponding to the delay time of a reference clock from a reference clock generating circuit. The regulation time determining circuit determines a regulation time based on the value detected by the delay time detecting circuit so that the regulation time is an integer multiple of the reference clock. The counter circuit is triggered by the trigger signal to count the reference clock through a specific value. The delay regulating circuit employs a signal related to the regulation time from the regulation time determining circuit, to delay the signal output from the counter circuit by the regulation time.

A testing device performs testing on a multistage multi-branch optical network, which contains optical lines (such as optical fibers) that are connected together at connection points (e.g., optical couplers) in a multistage multi-branch manner. An OTDR measurement device uses software to perform fault determination with respect to the multistage multi-branch optical network. Herein, optical pulses are input to an input end of the multistage multi-branch optical network, wherein they are reflected at certain portions of the optical lines and the connection points while propagating through the optical lines. Then, reflected beams are returned to the input end and are mixed together as response light, which is measured by the OTDR measurement device. The response light is converted to a plurality of digital waveform data representing a measured waveform, which is then divided into multiple ranges on the basis of the Fresnel reflection points and connection points. Separative analysis is performed on the digital waveform data belonging to each of the ranges of the measured waveform. The separative analysis is repeated at measuring times, which are determined in advance. So, the fault determination is made by comparing results of the separative analysis, which are obtained at the measuring times respectively. By the fault determination, it is possible to determine a fault line and a fault location (or fault distance) as well as a fault time.

Testing device for multistage multi-branch optical network

The present invention relates to an electro-optic sampling oscilloscope which carries out measurement of a measured signal using an optical pulse generated based on a timing signal from a timing generation circuit. The timing generation circuit includes a frequency measurement circuit which generates a gate signal for a gate interval which is a specified multiple N of the cycle of the desired sampling rate, and counts the input trigger signals during the gate interval of the gate signal; a division circuit which divides the count value of said frequency measurement circuit by the specified multiple N, and determines a divider ratio; and a frequency divider which divides the trigger signals by the divider ratio determined by the division circuit, and outputs the result as the timing signal.

Growing community of inventors

Tokyo, Japan

Nobuaki Takeuchi