The Furukawa Electric Co., Ltd.

Nidec Copal Corporation

Hitachi Media Electronics Co., Ltd.

Yasushi Horie

Kazuo Chiba

Minoru Saito

Seiji Ono

Naomitsu Kuroda

Eiji Okubo

Kunio Negishi

An optical element feeding device driving method and an optical disk apparatus capable of detecting biting in a stepping motor and conducting restoration. The optical disk apparatus includes an optical element feeding device including a movable frame for supporting a spherical aberration correcting lens to move the lens in optical axis direction, a spring for applying force to the frame in the direction, a sensor for detecting a lens reference position, a stepping motor, and a lead screw and a nut for converting motor rotation into the direction, a motor driving circuit, a decision circuit for judging abnormality when an output of the sensor does not change even if the driving circuit outputs a driving signal to the motor after reference position detection, and a changeover circuit for lowering a driving frequency than in ordinary operation, based on an abnormality signal.

Optical element feeding device driving method and optical disk apparatus

A communication cable is provided that satisfies the requirement of Cat.6 for near-end cross talk wherein the difference between the maximum and minimum values of delay time among the four twisted wire pairs constituting the cable is within 25 ns/100 m. The communication cable is made by entwining four twisted wire pairs (T,), (T,), (T,), (T,) made by twisting pairs of insulated wires made by covering electrically conductive wires by polyolefin thermoplastic resin with each pair being twisted with a twist pitch different from the others (pitch: P,<P,<P,<P,) and the inter-pair interposer (,) made of polyolefin thermoplastic resin, while being entwined with each wire pair, around a central interposer (,) made of polyolefin thermoplastic resin having cross sectional area of S,. Cross sectional area S,of the central interposer (,) satisfies the relationship of inequality S,&gE;&lsqb;&lcub;4.1 d/(1&plus;{square root over (2)})&rcub;&middot;0.35&rsqb;,&times;&pgr;, while the inter-pair interposer (,) that is entwined with the twisted wire pairs is located at such a position as adjoins the twisted wire pair (T,) having the least pitch P,and does not adjoin the twisted wire pair (T,) having the largest pitch P

Communication cable

A communication cable formed by cabling units such that each two adjacent units have different twist pitches, each unit including insulated wire pairs twisted together. A twist pitch P.sub.i of insulated wire pair T.sub.i selected among insulated wire pairs constituting a unit U.sub.i, and a twist pitch P.sub.j of insulated wire pair T.sub.j selected among insulated wire pairs constituting a unit U.sub.j, are different. Twist pitches P.sub.i and P.sub.j are selected from a region which satisfies expression (1) and either (2) or (3). Twist pitch P.sub.i and twist pitch P.sub.k of insulated wire pair T.sub.k selected among insulated wire pairs constituting a unit U.sub.k, are selected from a region which satisfies expression (4) where twist pitches P.sub.i and P.sub.k are in compliance with prior conditions given by (4). In the following expressions, x represents a unit diametrical component, y represents a unit lengthwise component and d is the outside diameter of insulated wires which constitute the insulated wire pairs.

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Tokyo, Japan

Yasushi Horie