Mitsubishi Denki Kabushiki Kaisha

Keiichi Nishikawa

Yukio Izumi

Atsuo Onoda

Hidetada Nagaoka

Yuuji Oomura

Masao Sato

Akira Hashimoto

Yasutaka Mizutani

Kazuo Hasegawa

Yoichi Muratomi

Masayoshi Kamo

Yuji Ohmura

Hiroshi Ito

Kazuya Oda

Satoru Akutsu

Hideo Yoshida

Takahiko Nakamura

Shigemasa Yoshida

Katsumi Kurita

Yasuhide Kasagi

Yuzou Maruta

Mitinaga Suzuki

Kiyotaka Hoshi

Hideto Nishimura

Koichi Okubo

A head assembly moving along a long side of a magnetic card, more than one magnetic head rotating in the head assembly for reading/writing data, a rotary transformer and a carriage with a card holding mechanism for keeping a card at a predefined position are provided in a card reader of the present invention. A rotating part of the rotary transformer in the head assembly receives and sends a signal to the magnetic head and a fixing part of the rotary transformer is connected to a reading/writing circuit. On the card of the present invention, which is usually rectangular, there are tracks defined by plural arcs. The arcs are on plural same-size circles whose centers are aligned on one line along the long side of the card. A magnetic card or an optical card can be used for the present invention.

Card drive apparatus and card

An identification sequence issuing device comprising a code converter portion for converting an identification sequence character string that may include letters, numerals, and the like, into a string of character codes having one-to-one correspondence to the characters in the character string, and a check and selection portion for selecting as an identification sequence the character string corresponding to a character code string that is determined to meet a Reed-Solomon code rule with each character code being a symbol of the Reed-Solomon code and the character code string length being the length of the Reed-Solomon code. The identification sequence is issued based on the Reed-Solomon code of a generating polynomial having a plurality of initial elements as roots, and for additional issuing, identification sequences are issued based on the Reed-Solomon code with the number of roots of the generating polynomial reduced by 1.

Identification sequence issuing device and identification sequence

A flexible disk drive unit including a spindle motor for driving to rotate a magnetic disk; magnetic heads opposing the magnetic disk; a carriage attached to a frame and movable in a radius direction of the magnetic disk; wherein the frame and a motor base constitute a common member and the spindle motor is of a sensorless drive system and is directly attached to the frame; and wherein the frame is provided with an attaching hole for erecting a bearing of the spindle motor of the sensorless drive system on the frame.

Frame for flexible disk drive unit having distortion prevention hole and

A brushless motor driving circuit is provided for obtaining a reliable starting and stable rotation driving irrespective of the load condition of the motor. The brushless motor driving circuit has a terminal voltage detector located at each phase of the armature windings of the motor, a terminal voltage compensator for adding or subtracting a compensation value to/from the terminal voltage of the armature windings detected at respective phases during actual driving periods, and a comparator for comparing respective terminal voltages to obtain a rotor location signal after compensation has been performed. The compensation value is determined by a resistor of the armature winding and a winding current. The armature windings are driven by the rotor location signal detected at the comparator.

Drive circuit for brushless motor

A method of encoding position information of each recording portion on a recording medium with a predetermined number of information units, which includes the step of composing position information codes such that the first position information code of the first recording portion is different by one information unit from the second position information code of the second recording portion which is spaced by one recording portion from the first recording portion, by two information units from the third position information code of the third recording portion which is spaced by two recording portions, and by three information units or more from the fourth position information code of the fourth recording portion which is spaced by three recording portions or more.

Method of encoding position information

A magnetic recording and reproducing circuit comprises a recording and reproducing head including a recording coil; an erasing head disposed upstream of the recording and reproducing head and including an erasing coil; a flip-flop which receives pulse-shaped record data and outputs an output signal which reverses the state in accordance with the pulses of the recording data; a delay circuit which receives the output of the flip-flop and delays such output by a predetermined period of time; a record driver which receives the output of the delay circuit for causing a recording current to flow through the recording coil of the recording and reproducing head; and an erasing circuit for causing an erasing current to flow through the erasing coil of the erasing head at the time of recording.

Digital magnetic recording and reproducing circuit for suppressing

Magnetization inversion data at different frequencies are recorded as part of servo information before and after an erasing gap between a data sector and a servo sector, the time interval between pulses read out from these magnetization inversion data is detected using a gap detection timer, and a timing for reading out servo information is obtained according to the result of detection by the gap detection timer.

Method of recording and detecting servo information for positioning

Growing community of inventors

Kanagawa, Japan

Keiichi Nishikawa