Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention relates to an electro-optic sampling oscilloscope. This electro-optic sampling oscilloscope carries out measurement of measured signal by using an optical pulse generated based on a timing signal generated from a timing generation circuit synchronous with a trigger signal, providing: a timing generation circuit comprising a fast ramp circuit that outputs a ramp waveform using said trigger signal as a trigger, a slow ramp circuit that increases stepwise and sequentially the output value according to said timing signal; a comparator circuit that compares the output of said fast ramp circuit and the output of said slow ramp circuit and outputs the results of this comparison; and a gate circuit that limits the output of said comparator circuit by closing a gate only when the output of said comparator circuit is unstable based on the input trigger signal and timing signal.

Abstract: The present invention relates to an electro-optic sampling oscilloscope in which an electric field generated by a signal to be measured is coupled with an electro-optic crystal, and an optical pulse outputted from an optical pulse output circuit is caused to enter the electro-optic crystal, and the waveform of the signal to be measured is observed using the polarization state of the optical pulse. The optical pulse output circuit has as the input light thereof a sample optical pulse amplified by an optical amplifier circuit, and outputs, as an optical pulse, the output from an optical filter which blocks the propagation of the spontaneously emitted light of the optical amplifier circuit.

Abstract: An electro-optic sampling oscilloscope (or EOS oscilloscope) is designed to perform measurement such that an electro-optic sampling probe (i.e., EOS probe) is brought into contact with a measured circuit. Optical pulses are input to the EOS probe, wherein they are varied in polarization states in response to the measured circuit. Then, an electric signal output from the EOS probe is amplified to produce a receiving light signal. The receiving light signal is subjected to sampling operations using a first pulse signal to produce detection data, while it is also subjected to sampling operations using a second pulse signal to produce noise data. Herein, the first pulse signal consists of pulses which emerge in synchronization with the optical pulses respectively, while the second pulse signal delays from the first pulse signal by a prescribed delay time. Then, measurement data are produced by subtracting the noise data from the detection data.

Abstract: An electro-optic sampling oscilloscope facilitates adjustment of signal-to-noise ratio caused by electrical, optical and temperature factors.

Abstract: A signal processing circuit is provided for an electro-optic probe, which is used to perform testing of a printed-circuit board of high-speed processing. When laser beams are incident on the electro-optic probe which is brought into contact with the printed-circuit board, they are changed in polarization and are then converted to electric signals. The electric signals are amplified and are then subjected to analog-to-digital conversion to produce digital data. The laser beams (or optical pulses) are generated based on sampling pulses used for sampling of the analog-to-digital conversion. Herein, the sampling pulses are created based on a sweep signal and a step-like signal. The sweep signal increases in level with a certain slope and then decreases suddenly in one period of a trigger pulse signal. The step-like signal increases in level in a step-like manner, wherein it is increased by a predetermined level in response to each of the sampling pulses.

Abstract: A multi-branched optical line testing apparatus can automatically detect a faulty line in multi-branched optical lines and the distance to the fault point. An optical pulse is introduced to the branch point of optical fibers and is reflected inside the respective optical fibers. The waveform of the returning response light is analyzed by an optical time-domain reflectometer (OTDR) measuring apparatus to detect a fault in the respective optical fibers and to determine the fault point. The OTDR measuring apparatus periodically converts the response light which is returned from the respective optical fibers into a digital waveform data group, calculates the attenuation ratios of the respective optical fibers by performing separation analysis of the digital waveform data group, and determines the faulty line and the position of the fault point based on the change of the attenuation ratio of the respective optical fibers.

Abstract: The optical reflector plates 11, 12 and 13 are connected at the ends of the optical fiber cables 8, 9, and 10, respectively. An optical waveguide directional coupler 2 which has at least one input common terminal A and at least two output terminals B and C is provided between an OTDR 1 and a measuring optical fiber cable 5. The output terminal B is connected to an end of the optical fiber cable 6, and the output terminal C is connected to an optical reflector plate 4 through an optical variable attenuator 3 which can changed the optical attenuation of passing light. The OTDR 1 supplies a light pulse to the input common terminal A, and measures the optical attenuation of the measuring optical fiber cable 5 by using differences in the intensity of reflected light pulses, which are reflected at each optical reflector plate 4, 11, 12, and 13.

Abstract: A high-power light pulse generating apparatus in which an optical fiber doped with a rare earth element is used in an optical system for facilitating control and and adjustment of the apparatus. The light output power and the pulse width thereof can be varied simply by changing the characteristics and the length of the optical fiber. In the high-power light pulse generating apparatus, an output of an optical pumping light source (2) is inputted to an optical coupler (3) which constitutes an optical loop in cooperation with the optical fiber (1) doped with a rare earth element, an optical decoupler(4), an optical switch (5A), an isolator (7) and an input port of the optical coupler (3). By turning on the optical switch (5A), a high-power light pulse can be generated through the optical loop and extracted from an output port of the optical decoupler (4).