Ando Electric Company

Other

The Kansai Electric Power Co., Inc.

Minami Machine Co., Ltd.

Takao Minami

Nobuaki Takeuchi

Koichi Shinozaki

Takamu Genji

Naoyuki Nozaki

Yoshiyuki Sakairi

Keiichi Shimizu

In a light wavelength dispersion measuring apparatus , three band-pass filters BPa to BPa are connected in parallel, three band-pass filters BPb to BPb are connected in parallel, and three phase comparators PCa to PCc are connected in parallel for making it possible to conduct phase difference measurement of the nth-order harmonics (n&equals; ) at the same time, so that a wavelength dispersion calculator can calculate the wavelength dispersion values of the nth-order harmonics (n&equals; ) at the same time. As a result, measurement time of measuring the wavelength dispersion characteristic in the light wavelength dispersion measuring apparatus can be shortened.

Light wavelength dispersion measuring apparatus and light wavelength dispersion measuring method

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

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

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.

Multi-branched optical line testing apparatus

In an optical fiber testing method, light are supplied to a measuring optical fiber so that return light, consisting of back-scattering light and Fresnel-reflection light, is outputted from the measuring optical fiber. A waveform representing the return light is used to perform testing of the measuring optical fiber. Herein, a detection range of the waveform used for detection of connections is defined and is partitioned into a plurality of regions in connection with Fresnel-reflection space. Then, at least a noise index and a constant are calculated for each region; and HOUGH conversion is performed on each region of the waveform. In addition, a center-value filtering process is performed, using the constant, with respect to each region of the waveform to create a filtered waveform. Further, a mean difference process is performed on the filtered waveform to create a mean difference waveform. A location of a temporary connection is set at a specific location of the mean difference waveform whose level exceeds a predetermined range. Approximate lines are calculated with respect to a left-side section and a right-side section of the temporary connection on the mean difference waveform. A connection loss is calculated for the temporary connection based on the approximate lines. Then, a decision is made, based on the connection loss, as to whether or not the temporary connection indicates a real connection. Thus, it is possible to automatically detect locations of connections and connection loss with high precision.

Optical fiber testing method for measuring connection location and

In an optical line testing device, light pulses are radiated to an optical line so as to receive response light, corresponding to each of the light pulses reflected by the optical line, for a certain period of time. The response light is converted to waveform data. The waveform data are averaged to create averaged data. The averaged data are stored in a memory and are also used to visually display a response waveform corresponding to the response light. A human operator manipulates an operator console while looking at the response waveform so as to analyze the response waveform, thus detecting a property of the optical line. A data range is set between first data and last data selected from among the averaged data representing the response waveform. According to an optical line testing method, the data range is partitioned into several regions so that an approximate line is calculated, using a method of least squares, with respect to each of the regions. Based on the relationship between the approximate line and the level of the response waveform, the property of the optical line is measured with respect to a terminal end of the optical line, a position of Fresne's reflection, and a connection loss of the optical line.

Optical line testing device and method for automatically and efficiently

A thin plate cutting/joining apparatus includes a cutting apparatus for pressing the front end of a following thin plate and the rear end of a preceding thin plate together and cutting the pressed front and rear ends of the thin plates in stepped scarf shapes; an adhesive coating apparatus for coating an adhesive on the cut surfaces of the end portions of the thin plates; and a joining apparatus for pushing the thin plates coated with the adhesive against each other and vertically pressing them, so as to joining the end portions of the thin plates.

Growing community of inventors

Tokyo, Japan

Takao Minami