Abstract: A cutting tool having cutting edges made of a high speed tool steel exhibiting very high wear and anti-chipping resistances, and sufficient toughness is provided. The high speed tool steel consists essentially of by weight C:0.6 to 1.8%, Si:1.2% max, Mn:0.5% max, Cr:3.5 to 5.0%, Mo:10% max, W:21% max, V:2 to 4% and Co:7 to 10%, the balance being Fe and incidental impurities, and the steel of the cutting edge comprise MC-type carbide grains each having a maximum equal value diameter of a circle ranging substantially 5 to 14 &mgr;m, and the MC-type carbide grains having an equal value diameter of the circle ranging substantially 5 to 14 &mgr;m have a ratio between short and long diameters ranging over substantially 0.3.

Abstract: An optical frequency sweep signal generator using an optical frequency variable bandpass filter which can be practically used is provided.

Abstract: The invention offers an optical fiber amplifier with good frequency characteristics which allows the gain to be held constant even without an input signal beam and allows gain control with respect to input optical signals with high-speed power fluctuations. An excitation beam source 8 supplies an excitation beam for light amplification and a control beam source 15 supplies a control beam for controlling the gain to an EDF 4 which amplifies a signal beam by means of optical excitation. An excitation beam monitor 9 measures the power of the excitation beam when inputted to the EDF 4 and an excitation beam monitor 12 measures the power of the excitation beam when outputted from the EDF 4. A comparator 11 calculates the ratio between the power measured by the excitation beam monitor 9 and the power measured by the excitation beam monitor 12. A drive circuit 14 controls the power of the control beam supplied by the control beam source 15 based on the results obtained by the comparator 11.

Abstract: An optical polarization controller comprises a polarization control element, a polarizer, a light divider and a photo-detector. The polarization control element rotates a plane of polarization of an Input signal light by a rotation angle in a predetermined rotational direction and outputs the result as a rotated signal light. The polarizer extracts a component of the rotated signal light having a predetermined plane of polarization and outputs the component as a polarized signal light. The light divider divides the polarized signal light into a plurality of polarized signal lights which have the same planes of polarization as the plane of the polarized light outputted by the polarizer. The photo-detector detects a level of one of the plurality of polarized signal lights and supplies a control signal indicating the level to the polarization control element.

Abstract: A noise determination apparatus for simple and precise determination of a noise factor of an optical fiber amplifier is presented. An optical pulse Pin is inputted via an optical coupler 2 into an optical looping circuit 14, and for every loop around the circuit 14, the spontaneous emission light generated in a rare-earth doped optic fiber amplifier 4 is integrated. The amplitude of the light intensity of the optical pulse train outputted from the optical splitter 3 decreases as the looping cycles are increased, and ultimately, the light intensity of the accumulated spontaneous emission light becomes equal to that of the optical pulse train. The pulse train outputted from the photodetector 7 diminishes. The number of pulses in the looping process from the initial pulse train to the expiration event are counted by means of a pulse counting device 8.

Abstract: In an optical transmission system applicable to a SDH network, communication between two line terminating equipments is performed in a form of a STM frame composed of a SOH field and a payload, which is determined by CCITT recommendations. The line terminating equipment provides a FEC circuit which is preferably arranged at a location between MSP and MST function blocks. The FEC circuit is designed to perform coding/decoding operations, using a cyclic Hamming code, directly on each AU-4 message derived from the STM frame. Otherwise, the FEC circuit performs operations on each k-bit interleaved AU-4 message (where `k` is an integer larger than 1). Check bits generated by a FEC coding circuit are written into undefined byte areas in a MSOH field, and error correcting is performed at a decoder circuit on the basis of embedded check bits, therefore FEC operations are performed within a multiplex-section layer.

Abstract: In an article transporting system, a first linear moving arm and a second linear moving arm are juxtaposed to each other so as to be moved linearly while keeping a parallel positional relationship with each other. First end portions of the linear moving arms are coupled to an article transporting unit through first and second links. A linear drive mechanism is provided for linearly moving the article transporting unit in a direction perpendicular to the moving direction of the linear moving arms by the linear movement of the first and second linear moving arms. The first and second linear moving arms are synchronously linearly moved in opposite directions to each other. In this case, to avoid an unstable posture of the article transporting unit during the movement, a posture maintaining device is provided between one of the first and second linear moving arms and the article transporting unit.

Abstract: The object of the present invention is to control the amplification rate of a photoperiodic circuit by stable negative feedback control, thereby suppressing fluctuations in the circulating light in the photoperiodic circuit. The circulating light in the photoperiodic circuit is converted into an electrical signal, indicating the intensity of the circulating light, which is held in a first sample-and-hold circuit. Additionally, an electrical signal indicating the intensity of circulating light of the circuit previous to that of the first sample-and-hold circuit is held in a second sample-and-hold circuit. The difference in the value between the electrical signals which indicate intensities of the circulating light are determined by a subtraction circuit. The result is supplied to an addition circuit through a third sample-and-hold circuit.

Abstract: A high fidelity optical amplifier having a stable amplification gain is presented. The problem of signal distortion in an output optical signal caused by an imbalance of light energy generation and consumption within the optical fiber is resolved by generating a delayed correction signal to be used in a feedback control circuitry. An incoming optical signal is split into two signals: one split signal is forwarded to a photo-detector element for generation of the correction signal while the other split signal is forwarded to a signal delay circuit. The optical delay circuit delays the timing of inputting the correction signal into output optical fiber for a specific duration of time to attain a full amplification gain within the optical fiber. The correction signal generation circuit performs differentiation of an electrical input signal followed by detection and selection of a maximum amplitude over a standard reference voltage.

Abstract: A method and an apparatus for monitoring the noise figure of an optical amplifier such as used in linear repeaters in an optical transmission system formed by cascaded linear repeaters. The apparatus includes at least one optical amplifier for amplifying input signal light and a narrow bandwidth optical filter for removing amplified spontaneous emission (ASE) light generated at the optical amplifier. A gain detector is provided to detect the gain of the optical amplifier and an ASE optical power detector detects an optical power of the ASE light generated at the optical amplifier. The apparatus includes a splitter for splitting light entering into the narrow bandwidth optical filter and a local oscillator for generating local light having a wavelength displaced from a wavelength of the input signal light. The light split by the splitter is coupled with the local light generated by the local oscillator. An optical power detector makes a heterodyne detection of the optical power of the coupled light.

Abstract: An optical amplifier using either rare-earth doped optical fiber, which can amplify an optical signal when a pumping light is injected, or a laser diode amplifier, which can amplify an optical signal by injection of an electric current. The amplifiers being of simple construction and having a gain which can be maintained constant through feedback control based on the detection of spontaneous emission from the sides of either the rare-earth doped optical fiber or the laser diode. The control being performed without the need for detection of input or output optical signal of the optical amplifier.

Abstract: A water-vapor permeable, waterproof coated fabric having a fibrous base fabric, and a porous film coated on one side of the base fabric. The porous film comprises a synthetic polymer composed mainly of a polyurethane resin and inorganic fine particles having a mean particle diameter of not more than 0.1 .mu.m. In the porous film, microcells intercommunicate in the thicknesswise direction of the film to form a honeycomb skin core structure having a diameter of 1 to 20 .mu.m. The porous film has a multiplicity of micropores having a diameter of not more than 1 .mu.m. The coated fabric has waterproof and water-vapor permeability characteristics sufficient to meet such performance characteristics required in various applications, such as rainwears, military garments, and sportswears.

Abstract: At least one optical repeater is connected in series to an optical signal transmission fiber of an optical fiber cable interconnecting transmitting and receiving terminals, and the optical repeater has an optical amplifier which is excited by pump light to amplify signal light. The pump light is supplied from the outside of the optical repeater, and the pump light supplied is input into the optical amplifier via at least one of its input end and output end. The optical repeater may include an optical divider for dividing the pump light supplied thereto into two, which are input into the optical amplifier via its input end and output end, respectively.

Abstract: Dual video recording/reproducing apparatus includes a video playback unit, a video recording unit having recording circuitry for recording a video output signal from the video playback unit, as well reproducing circuitry for reproducing a video signal, and a sub-picture signal former responsive to a video signal supplied thereto for providing a sub-picture signal adapted to be displayed as a sub-picture insert of a main picture. A switch couples either the video output from the video playback unit or the video output from the reproducing circuitry included in the video recording unit to the sub-picture signal former. The video signal which is not coupled to the sub-picture signal former constitutes the main picture signal; and the sub-picture and main picture signals are combined to form a display signal which, when displayed, produces a main picture and a sub-picture insert.

Abstract: In optical branching equipment which is supplied with an optical signal of a first wavelength band from a trunk line terminal equipment via a trunk line cable and is inserted in the trunk line, the optical signal is normally provided to the trunk line cable after being bypassed from a branching circuit to branch line terminal equipment connected to a branch line cable, and when trouble develops in the branch line, the optical signal is delivered to the trunk line cable via a short circuit. In the short circuit there is inserted an optical limiter amplifier which is capable of amplifying light of the first and second wavelength bands. Normally the optical limiter amplifier is saturated by control light of the second wavelength supplied from the branch line terminal equipment via the branch line cable, and consequently, the optical signal of the first wavelength band is suppressed.

Abstract: A videotape tape guide for guiding videotape in a videocassette. The videotape tape guide is comprised of an elongated cylinder having first and second open ends. A groove extends longitudinally from the first open end of the elongated cylinder to the second open end of the cylinder. The longitudinally extending groove allows the material required to form the tape guide to be reduced, thereby reducing the cost of the tape guide. Further, the groove allows firm seating in the videocassette to prevent rotation of the tape guide when positioned therein.

Abstract: A working apparatus for working a crankshaft having a journal portion and a crank pin includes first and second follow-up mechanisms. The first follow-up mechanism has first and second support members for rotatably clamping the journal portions therebetween. The second support member is moved in relation to the first support member by a first actuator. The second follow-up mechanism has third and fourth support members for rotatably clamping the crank pin therebetween. The fourth support member is moved in relation to the third support member by a second actuator. A first fillet roller is provided at the first support member and pressed against the journal portion, to roll thereon, and a second fillet roller is provided at the third support member and pressed against the crank pin, to roll thereon.

Abstract: A moisture-permeable waterproof laminated fabric comprising a water-repellant base fabric and at least one porous film provided on one surface of the base fabric. The porous film is formed of a synthetic polymer composed chiefly of a polyamino acid urethane resin and has numerous fine pores provided by microcells which are continuous in the direction of its thickness. The laminated fabric has satisfactory waterproofness and moisture permeability as required for munition, survival and sport uses.

Abstract: Method for producing an interlaced multifilament yarn by rubbing and scratching a material multifilament yarn with a rotary rough surface member and with such intensity that individual filaments constituting the filament yarn are not substantially broken, the rotary surface member having projections which are smaller than the cross-sectional diameter of the individual filaments of the material yarn; diffusing a jetted fluid which is jetted in the yarn running direction along a predetermined yarn passage from a jetting aperture of a supply conduit through a nozzle formed with a rectifying and diffusing portion having a substantially uniform cross-section, and impinging the diffused jetted fluid against the running material multifilament yarn so that the individual filaments of the multifilament yarn mostly vibrate in a direction substantially parallel to a plane defined by the yarn running direction and the fluid jetting direction, the vibration taking place in a section of the yarn passage facing the rectifyi

Abstract: Method for producing an interlaced multifilament yarn comprising previously rubbing and scratching a material multifilament yarn with an intensity such that the individual filaments constituting the multifilament yarn are not substantially broken by a rotary rough surface member having sharp projections which are smaller than the cross-sectional diameter of the individual filament of the multifilament yarn; then diffusing at least one jetted fluid, each jetted in the yarn running direction along a predetermined yarn passage from a jetting aperture of a supply conduit through a nozzle formed with a rectifying and diffusing portion having a substantially uniform section with the supply conduit being fixed with respect to the members defining the yarn passage; and then impinging the diffused jetted fluid against the running material multifilament yarn so that the individual filaments of the multifilament yarn mostly vibrate in a direction which is substantially parallel to a plane defined by the yarn running dir