Abstract: A disk drive self-servo writes on a storage disk. Servo bursts are self-written along a track using a transducer, a position error signal (PES) indicating repeatable runout due (RRO) for the servo bursts is determined using a reference pattern, an embedded runout correction (ERC) value is calculated based on the PES and stored in a corresponding servo sector, and then the disk drive self-writes other servo bursts.

Abstract: A disk drive self-servo writes on a storage disk. Servo bursts are self-written along a track using a transducer, a position error signal (PES) indicating repeatable runout due (RRO) for the servo bursts is determined using a reference pattern, an embedded runout correction (ERC) value is calculated based on the PES and stored in a corresponding servo sector, and then the disk drive self-writes other servo bursts.

Abstract: A method and system for self-writing track locations of a data disk in a disk drive in order to reduce overall track runout are disclosed. First set of servo bursts are self-written along a track via a transducer, and repeatable runout correction values for the first servo bursts are calculated. Then, second servo bursts are self-written along the track via the transducer such that the first and second servo bursts form a plurality of servo sector patterns that define the track centerline, wherein the second servo bursts are positioned using said correction values to essentially compensate for the runout in the first servo bursts and reduce the overall track runout.

Abstract: In the spindle control system of the present invention the compensator is divided into two portions. The first portion is driven by a first clock signal at a first frequency and a second portion is driven by a second clock signal at a second frequency derived from the first clock signal. In particular, the integrator utilizes a clock which increases the time measurement to be a longer interval than the measurement utilized for the remainder of the compensator circuit. This allows the absolute speed to be adjusted with a high resolution independent of the gain. Therefore, the gain can be maintained and the loop dynamics are preserved, maintaining dynamic range and stabilization while increasing the resolution of control of the spin speed.

Abstract: An automatic digital control system includes a proportional integral derivative (PID) compensator in which the digital differentiator portion, with its associated zero-order hold, is implemented according to an algorithm that reduces phase loss as a function of frequency. The digital differentiator is based only on a present error sample so that the output of the digital differentiator (with its ZOH) is made to resemble an amplitude-balanced step function (i.e., a doublet) during a given sample period T. The step transition occurs at one-half of the period (i.e., at T/2). Another embodiment further reduces phase loss by confining the output waveform of the differentiator to some fraction of the total sampling period. During the remaining portion of the sampling period the digital differentiator (again, with its associated ZOH) is forced to some desired reference level.

Abstract: Apparatus and accompanying methods for a custody transfer metering system, that illustratively utilizes a dual tube Coriolis mass flow rate meter and provides accurate totalized mass flow measurements and fault detection capability, are described. Specifically, this apparatus senses time differences occurring in the movement of both flow tubes. Four such time difference measurements are taken and combined in a pre-defined manner so as to eliminate differences appearing in the electrical characteristics of analog circuitry connected to each of two sensors used to detect tube movement and thereby to advantageously increase measurement accuracy. Mass flow rate of the fluid passing through the meter is determined, as a function of the combined time measurements, in terms of normalized mass and time units and thereafter converted into user specified mass units/unit time. The resulting converted value is used to compute totalized mass flow and to set and/or update various system outputs.

Abstract: An electronic signal processor for substantially eliminating timing errors in determining the time difference between two periodic analog signals which uses switches that allow one of the two signals to be connected to one channel for digitizing that signal and the other signal to be connected to a second channel, then the switches, after about a cycle, reverse the connections. The measured time differences over two cycles are then added or subtracted to substantially eliminate timing errors caused by variations in the operational characteristics of electronic components in the signal processor.

Abstract: A beam alignment system and method for aligning a first radiation beam with respect to a second radiation beam as these beams share a desired optical path. Beam steering means, such as a galvonometer controlled mirror, steer the alignment of the first beam as it enters the shared optical path. Detection means are employed to sense the relative alignment between the first and second beams as they travel through the shared path. This sensed alignment is compared to a desired alignment, and a position error signal is generated to indicate the error therebetween. The position error signal, in turn, is used to steer the galvonometer controlled mirror in order to force the beam alignment error between the two beams to zero.

Abstract: A beam alignment signal processing system wherein a true beam position error signal is generated regardless of beam intensity. This beam position error signal is used within a beam alignment system that maintains a desired alignment between first and second beams traveling in parallel along a desired optical path. A detector senses the position of the beams as the beams (or portions of the beams) are directed onto a surface thereof. The detector generates a set of position signals that indicate the position at which a beam, or at which an energy centroid associated with a plurality of beams, falls upon the detector surface. A first set of position signals is generated corresponding to the position of the first beam on the detector surface with the second beam turned off. These signals are stored in signal storage means. The second beam is turned back on, and a second set of position signals is generated corresponding to the position of the centroid of the first and second beams on the detector surface.