Abstract: In an optical fiber ferrule assembly, a bare optical fiber, an end coating of which is removed, is inserted and fixed into the central hole of a ferrule body. By setting the distance between a boundary point at which the bare optical fiber is fixed at the rear end of the ferrule body and a next point at which the bare optical fiber is fixed to a fixing member which is formed integrally with the ferrule body via a coating of an optical fiber core to the range of 0.5 to 6 mm, more preferably, to the range of 1 to 4 mm, stress concentration at the boundary point at which the bare optical fiber is bonded and the point at which the optical fiber core is fixed cab be reduced.

Abstract: In an optical fiber ferrule assembly, a bare optical fiber, an end coating of which is removed, is inserted and fixed into the central hole of a ferrule body. By setting the distance between a boundary point at which the bare optical fiber is fixed at the rear end of the ferrule body and a next point at which the bare optical fiber is fixed to a fixing member which is formed integrally with the ferrule body via a coating of an optical fiber core to the range of 0.5 to 6 mm, more preferably, to the range of 1 to 4 mm, stress concentration at the boundary point at which the bare optical fiber is bonded and the point at which the optical fiber core is fixed cab be reduced.

Abstract: An optical attenuator includes a holding sleeve, a pair of ferrules inserted into and fixed to the holding sleeve such that the ferrules oppose each other at base ends thereof at a predetermined distance between each base end, and an attenuating fiber inserted into and fixed to the pair of ferrules such that ends of the attenuating fiber are exposed. The optical attenuator is also provided with an opening in the holding sleeve so as to communicate with the outside. A filler is supplied into the sleeve through the opening.

Abstract: In an optical fiber ferrule assembly, a bare optical fiber, an end coating of which is removed, is inserted and fixed into the central hole of a ferrule body. By setting the distance between a boundary point at which the bare optical fiber is fixed at the rear end of the ferrule body and a next point at which the bare optical fiber is fixed to a fixing member which is formed integrally with the ferrule body via a coating of an optical fiber core to the range of 0.5 to 6 mm, more preferably, to the range of 1 to 4 mm, stress concentration at the boundary point at which the bare optical fiber is bonded and the point at which the optical fiber core is fixed cab be reduced.

Abstract: An optical attenuator includes a holding sleeve, a pair of ferrules inserted into and fixed to the holding sleeve such that the ferrules oppose each other at base ends thereof at a predetermined distance between each base end, and an attenuating fiber inserted into and fixed to the pair of ferrules such that ends of the attenuating fiber are exposed. The optical attenuator is also provided with an opening in the holding sleeve so as to communicate with the outside. A filler is supplied into the sleeve through the opening.

Abstract: An image vibration compensating apparatus is provided for properly compensating image vibrations while suppressing unnatural image vibrations after completion of intentional panning and tilting. A-D conversion is performed on an output signal of an X-direction gyro sensor and low frequency components are removed from the signal. The signal is then integrated at an integrator to be angle signal Ex. A panning detector detects a start and a stop of intentional panning from angle signal Ex. A subtraction value generator generates a value for canceling angle signal Ex resulting from the intentional panning. An angle control signal computing section cancels angle signal Ex resulting from the intentional panning with the value and outputs angle control signal VXref. An image vibration in the direction of panning is compensated based on angle control signal VXref.

Abstract: A method and apparatus for recording and/or reproducing signal on or from a recording medium, wherein correct tracking servo signals may be produced so that tracking errors may be detected correctly. The pilot signal from a recording amplifier 3, produced by frequency-dividing system clocks by a frequency divider 2, is recorded on the recording medium by a servo head 21 at the timing of a timing signal GP.sub.1. A tracking servo signal, obtained by reproducing the pilot signal by a recording/reproducing head 22, delaying the resulting signal by a delay circuit 4 and phase-shifting the resulting delayed signal by a phase shifting unit 5, is recorded at the timing of a timing signal GP.sub.2. The pilot signal and the tracking servo signal are reproduced by the recording/reproducing head 22 and the pilot signal is delayed by the delay circuit 4.

Abstract: A method and apparatus for recording and/or reproducing signal on or from a recording medium includes correct tracking servo signals which may be produced so that tracking errors may be detected correctly. The pilot signal from a recording amplifier 3, produced by frequency-dividing system clocks by a frequency divider 2, is recorded on the recording medium by a servo head 21 at the timing of a timing signal GP.sub.1. A tracking servo signal, obtained by reproducing the pilot signal by a recording/reproducing head 22, delaying the resulting signal by a delay circuit 4 and phase-shifting the resulting delayed signal by a phase shifting unit 5, is recorded at the timing of a timing signal GP.sub.2. The pilot signal and the tracking servo signal are reproduced by the recording/reproducing head 22 and the pilot signal is delayed by the delay circuit 4.

Abstract: The present invention provides a method of manufacturing a porous preform for an optical fiber, including the steps of removing impure particles from silica powder while being stirred in an alkaline liquid phase, and obtaining the porous preform for an optical fiber by applying the powder forming method to the silica powder used as a main raw material. The present invention further has a method of manufacturing a porous preform for an optical fiber, including the step of preparing a forming material by adding fine particles having a particle diameter satisfying the following formula (I) to the silica powder, and obtaining the porous preform by applying the powder forming method to the forming material: ##EQU1## wherein d: diameter of fine particles, and D: diameter of silica powder.

Abstract: In a motor control system, a first servo loop for a phase system and a second servo loop for a speed system are provided the pull-in operation of the motor during the transition time period is made stable, and also the operation efficiency of the low-speed CPU is not deteriorated. In the motor control system, the first servo loop is arranged by a speed detector for outputting a voltage corresponding to a frequency of a first reference signal used to set a rotational speed of the motor, a phase comparator for comparing a phase of the first reference signal with a phase of a control signal; and an adder for adding an output of the speed detector to an output of the phase comparator.

Abstract: A reference signal generator that operates in response to a digital control signal has an increased resolving power without the requirement for increasing the basic clock rate or increasing the bit capacity of a down counter by thinning a pulse from the basic clock signal each the down counter overflows so as to adjust the down-counting clock rate of the down counter. The down counter counts the higher-bit data of the digital control signal. The basic clock signal is multiplied by a decoded signal to obtain the adjustment of the down counting clock signal. The decoded signal is obtained by counting the overflow pulses from the down counter and decoding the counter output with the lower-bit data of the digital control signal.

Abstract: The present invention provides a method of manufacturing an optical fiber preform having the steps of disposing a rod member made of a silica-based material within a cavity of a mold, followed by loading a molding material within the mold cavity, and applying pressure to the mold from the outside to form a porous layer on the surface of the rod member and, thus, to obtain a porous preform, wherein at least one end portion of the rod member extends outside the mold cavity in the step of applying pressure to the mold. The particular method permits manufacturing a high quality porous preform free from splits or cracks, making it possible to obtain a high quality optical fiber preform free from residual bubbles.

Abstract: The method of manufacturing a silica glass preform comprises the steps of inserting a rod-like member mainly containing a ductile material, into a forming space of a mold, charging the remaining space of the forming space with a forming material containing silica glass powder or doped silica glass powder, compressing the mold charged with the forming material from outside such as to form a porous glass body of the forming material around the rod-like member, removing the rod-like member from the porous glass body, inserting a glass rod into the hole formed after removal of the rod-like member, purifying said porous glass body in which the glass rod is inserted, and consolidating said porous glass body purified in the above purifying step.

Abstract: A capstan servo device comprising a frequency generator for detecting the rotation rate of a capstan motor and generating two-phase FG signals mutually having a 90.degree. phase difference; a selector for selecting one of input four-phase signals produced from the two-phase FG signals and mutually having a 90.degree. phase difference; and a sync signal generator including an N-bit counter (where N.gtoreq.2) to receive a reference frequency signal inputted thereto and generating a sync signal by phase-comparing the two high-order bits of the frequency-divided output of the counter with the two-phase FG signals. In this device, the rotation speed of the capstan motor is controlled in accordance with an error voltage signal selected by the selector in response to the sync signal.

Abstract: A tape transport apparatus is comprised of a friction type capstan servo block having a friction type capstan driven by a capstan motor controlled by a capastan servo circuit in response to a control signal for determining a velocity of the capstan and a pulse signal generated in response to a rotation of the capstan motor, a reel servo block having a supply reel and a take-up reel driven by a supply and take-up reel motor controlled by a supply reel and take-up reel control circuit respectively, first and second tape tension detectors for detecting tape tension of the tape locating between the capstan and supply reel and between the capstan and take-up reel respectively, a control voltage generator for generating a control voltage, a tape tension control data generating circuit having a memory, the memory having a plurality of back tension characteristics data each of which is changed in response to the pulse signal so that the back tension of the supply reel motor is controlled in response to an outlet sign

Abstract: In a tape loading device in which a tape is drawn from a mounted tape cassette and loaded on a tape path which lies in front of the mounted tape cassette, a big capstan which is arranged in front of the mounted tape cassette is inserted into a space formed between the mounted tape cassette and a portion of the tape which has been loaded on the tape path, from a position where the big capstan does not interfere with the tape which is moved to the tape path, so that it is possible to make the diameter and length of the capstan large.

Abstract: A method for splicing optical fibers is provided which is applied to an optical fiber using, as the material of a clad layer, hexafluoroalkyl methacrylate, a residuum of which after pryolysis due to a thermogravimetric analysis is 10% or less by weight. The method comprises a step of removing a protective layer and a cushioning layer at an end portion of the optical fiber, to expose the clad layer, a step of positioning two optical fibers, the end portions of which have been treated, such that the end faces of cores of the two optical fibers are opposed and close to each other, and a step of heating the end portions of the two optical fibers by electrical discharge, to remove the exposed clad layer by pyrolysis and fusion bond the opposed end faces of the cores to each other.

Abstract: The present invention involves a method and apparatus to prolong the useful life of a drive tape used in a magnetic contact printer to advance master and copy tapes past a transcribing head to transcribe the signals from the master tape onto the copy tape. The present invention provides a method for using the entire length of the drive tape even though individual segments on different master tapes may be shorter than the length of the drive tape. In the method of the present invention the drive tape is rewound after each transcription only part of the way to the beginning of that transcription. The next transcription will then require the use of a part of the drive tape not used in the previous transcription. The apparatus of the present invention uses a digital logic circuit to carry out that method. The apparatus comprises a counter that senses the length of advance of the drive tape for each transcription and detectors that provide signals to terminate the rewindings of the drive tape at the proper points.