摘要:
Methods, systems and computer program products for compensating repeatable run-out (RRO) are described. In some implementations, RRO may be compensated by predicting the RRO and subsequently subtracting the predicted RRO from the actual value of the RRO to cancel out the undesired effect caused by the RRO during operation. More specifically, RRO generated at each spindle motor rotation may be predicted by measuring the position errors associated with the RRO with respect to a current position of a read/write head. A computational model then may be utilized to determine one or more correction factors to compensate for the RRO.
摘要:
A control system includes a write head that writes servo data on a rotating medium. A control module signals the write head to write a servo test track on the rotating medium and subsequent to a reference servo track. The reference servo track is written prior to an interrupt event. The control module detects a position of the servo test track relative to the reference servo track and signals the write head to write a new servo track based on the position after the interrupt event.
摘要:
A control system includes a write head and a control module configured to signal the write head to write a servo test track on a rotating medium at a position relative to a reference servo track on the rotating medium. The servo test track is written on the rotating medium subsequent to an interrupt event. The reference servo track having been written to the rotating medium prior to the interrupt event, detects the position of the servo test track relative to the reference servo track and signals the write head to write a new servo track on the rotating medium based on the detected position of the servo test track relative to the reference servo track.
摘要:
Methods, systems and computer program products for compensating repeatable timing variations associated with a spindle motor are described. Specifically, a repetitive error correction factor may be determined using a computational model which predicts timing variations. The correction factor can then be used to cancel the effect of the actual timing variations upon the spindle motor.
摘要:
Methods, systems, and apparatus, including computer program products, are described for calibrating spindle motor controllers. In one aspect, a method is provided that includes receiving a compensator output from a spindle motor controller that compensates for variations in a velocity of an associated spindle motor, and filtering the compensator output to compensate for a spindle motor system pole and produce a high frequency roll-off.
摘要:
Methods, systems, and apparatus include, in one aspect, a method including receiving from a controller a signal for controlling a device for rotating a machine-readable medium; and increasing a bandwidth of a transfer function corresponding to the controller by at least filtering the signal to compensate for a pole of the transfer function.
摘要:
Methods, systems and computer program products for compensating repeatable timing variations associated with a spindle motor are described. Specifically, a repetitive error correction factor may be determined using a computational model which predicts timing variations. The correction factor can then be used to cancel the effect of the actual timing variations upon the spindle motor.
摘要:
Systems and techniques to calibrate a control loop include, in at least one implementation, a system including the control loop configured to generate a clock signal and lock the clock signal to timing marks detected on a machine readable medium, a repetitive error correction module configured to receive a predicted phase and a corrected phase error for the clock signal, generate a predicted repetitive phase disturbance using the predicted phase and the corrected phase error for the clock signal, and calibrate a phase error to compensate for variations in repetitive phase errors in the clock signal using the predicted repetitive phase disturbance; and a servo track generator configured to generate servo tracks using the clock signal.
摘要:
Methods, systems, and apparatus, including computer program products, are described for calibrating control loops, specifically phase-locked loops. In one aspect, an apparatus is provided that includes an oscillator model that generates a predicted phase based on an input, a first averaging submodule that generates an average predicted phase over a predetermined number of samples, and a first summing submodule that receives a first corrected phase error and generates a predicted repetitive phase disturbance using the first corrected phase error, the predicted phase, and the average predicted phase.
摘要:
A light emitting diode (LED) lighting system includes a first string of first LEDs emitting light having a first color. A second string of second LEDs emits light having a second color and connected in series with the first string of first LEDs; A first switch and a second switch are connected in series. A regulator module is configured to modulate the first switch and the second switch to provide a desired current ratio. The desired current ratio corresponds to a ratio of a first current through the first string of first LEDs to a second current through the second string of second LEDs.