Abstract: A vibration extraction processing unit extracts a deflection component synchronous with a rotation from a clock signal of a non-contact sensor so as to correct a clock jitter. A clock generating unit generates a clock signal of any format frequency preliminarily set up according to the clock signal from the vibration extraction processing unit. A sector correction processing unit measures an error due to the frequency deflection so as to correct the writing start position for the format pattern signal of each sector containing a servo frame signal stored in a memory according to the measured error. Writing processing units read out the corrected format pattern signal from the memory according to a synchronous signal corresponding to a single turn of a disc and a format frequency clock signal and then writes into a disc medium face.

Abstract: A servo track writer for writing a servo track signal to a disk medium in a disk drive including the disk medium, a head for reading/writing information from/to the disk medium, and an internal actuator for moving the head across tracks formed on the disk medium. The internal actuator has a rotatable carriage for supporting the head. The servo track writer includes an external actuator having an arm, a solid deformation element provided in relation to the arm, and an effector mounted on the arm; an internal actuator control unit for controlling the internal actuator; an external actuator control unit for controlling the external actuator; a solid deformation element control unit for controlling the solid deformation element; and an arm position detecting device for detecting a position of the arm. The solid deformation element is divided into a first segment functioning as an actuator for minutely displacing the carriage, and a second segment functioning as a sensor for detecting a position of the effector.

Abstract: A vibration extraction processing unit extracts a deflection component synchronous with a rotation from a clock signal of a non-contact sensor so as to correct a clock jitter. A clock generating unit generates a clock signal of any format frequency preliminarily set up according to the clock signal from the vibration extraction processing unit. A sector correction processing unit measures an error due to the frequency deflection so as to correct the writing start position for the format pattern signal of each sector containing a servo frame signal stored in a memory according to the measured error. Writing processing units read out the corrected format pattern signal from the memory according to a synchronous signal corresponding to a single turn of a disc and a format frequency clock signal and then writes into a disc medium face.

Abstract: A servo track writer for writing a servo track signal to a disk medium in a disk drive including the disk medium, a head for reading/writing information from/to the disk medium, and an internal actuator for moving the head across tracks formed on the disk medium. The internal actuator has a rotatable carriage for supporting the head. The servo track writer includes an external actuator having an arm, a solid deformation element provided in relation to the arm, and an effector mounted on the arm; an internal actuator control unit for controlling the internal actuator; an external actuator control unit for controlling the external actuator; a solid deformation element control unit for controlling the solid deformation element; and an arm position detecting device for detecting a position of the arm. The solid deformation element is divided into a first segment functioning as an actuator for minutely displacing the carriage, and a second segment functioning as a sensor for detecting a position of the effector.

Abstract: A positioning device positions a driving unit of which a torque constant fluctuates depending on a position, whereby a proper quantization error is obtained even when a maximum current value in a movable range changes. The positioning device includes a position detector for detecting a present position of the drive unit, a control circuit for generating a digital drive command value corresponding to a positional error between a command position and a present position, a D/A converter for converting the digital drive command value into an analog voltage, and a driver, having a plurality of gains, for converting the analog voltage into the analog drive current with a selected gain. The control circuit selects the gain of the driver in accordance with the present position. The gain of the driver (voltage/current converting amplifier) is made variable and controlled corresponding to the position, and hence there is no necessity for covering the maximum current range with the digital command value.