Abstract: Dither circuitry includes harmonic signal generation circuitry configured generate a high order even harmonic of a base excitation signal. The dither circuitry also includes a combiner configured to generate a dithered excitation signal based on the high order even harmonic and the base excitation signal. The dither circuitry further includes an output terminal configured to output the dithered excitation signal to a sensor device.

Abstract: A servo writer is disclosed operable to write servo sectors on a disk to define non-circular servo tracks. The servo writer comprises control circuitry including a servo control system operable to measure a position of a head over the disk to generate a position signal, generate a position error signal (PES) representing a difference between the position signal and a reference signal, process the PES with a servo compensator to generate a control signal, and position the head over the disk in response to the control signal. A disturbance is induced into the servo control system, and while positioning the head over the disk in response to the control signal, a plurality of servo sectors are written on the disk to define a servo track, wherein the disturbance induced into the servo control system causes the servo track to be non-circular relative to a rotation axis of the disk.

Abstract: A recording target error rate is selected for one or more of data storage devices, and for each data storage device, a dither value is determined for each read/write head in the data storage device, wherein for each head, using a dither value for writing data, essentially provides the selected recording target error for all the heads.

Abstract: The present invention provides a tape drive apparatus enabled to directly and accurately detect dew condensation on a rotary head drum. Tape serving as a recording medium is drawn out of a cartridge. The drawn tape runs in such a way as to be wound on a tape takeup reel provided in a tape drive apparatus body. Signals are recorded on and reproduced from the tape by winding the drawn tape around the rotary head drum. This tape drive apparatus has a prethreading mechanism that brings the tape into slight contact with the rotary head drum before the tape is completely wound therearound. Dew condensation on the rotary head drum is detected by rotating the rotary head drum during a status in which the tape is brought by the prethreading mechanism into contact with the rotary head drum.

Abstract: The effective resolution of a Position Error Signal (PES) in a disk drive servo is increased by synchronously dithering the analog PES while sampling it with an Analog-to-Digital Converter (ADC). For each cycle of a burst field signal on a servo sector, a DC offset is added to the analog PES before sampling. The offset is changed periodically during the sampling of the burst field signal. The set of all DC offsets used is evenly spread over a range which is substantially equal to the size of the least significant bit of the ADC multiplied by a positive integer.