REGULATING TUNING RATE OF ADAPTIVE FILTER COEFFICIENTS FOR FEED-FORWARD DISTURBANCE REJECTION IN A SERVO CONTROL LOOP
First Claim
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1. A circuit comprising:
- a filter coefficient adaptation circuit that responds to an acceleration signal and a position error signal, which is indicative of head position error, by tuning filter coefficients of an adaptive filter to reduce the position error signal, the filter coefficient adaptation circuit responding to a characteristic of the acceleration signal to constrain a rate at which the filter coefficients are changed to track changes of the acceleration signal.
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Abstract
In a servo control loop, the rate of change of filter coefficients used by an adaptive filter to counteract external disturbances to head position is regulated in response to a characteristic of an acceleration signal. Regulating the rate of change of the filter coefficients may improve the stability of the servo control loop.
21 Citations
20 Claims
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1. A circuit comprising:
a filter coefficient adaptation circuit that responds to an acceleration signal and a position error signal, which is indicative of head position error, by tuning filter coefficients of an adaptive filter to reduce the position error signal, the filter coefficient adaptation circuit responding to a characteristic of the acceleration signal to constrain a rate at which the filter coefficients are changed to track changes of the acceleration signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method comprising:
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tuning filter coefficients of an adaptive filter circuit in response to an acceleration signal, which is indicative of mechanical vibration and a position error signal, which is indicative of head position error, to reduce the position error signal; operating the adaptive filter circuit responsive to the filter coefficients to filter the acceleration signal to generate a feed-forward signal that controls a head actuator to counteract disturbances to head position caused by the vibration; and regulating, responsive to a characteristic of the acceleration signal, a rate of change at which the filter coefficients are changed to track changes of the acceleration signal. - View Dependent Claims (16, 17, 18, 19)
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15. (canceled)
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20. A servo control circuit comprising:
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a finite impulse response (FIR) filter that filters an acceleration signal, which is indicative of mechanical vibration, using a plurality of coefficients weights that are applied to a plurality of time-delay filter taps of the acceleration signal to generate a feed-forward signal; a filter coefficient adaptation circuit that responds to the acceleration signal and a position error signal, which is indicative of head position error, by tuning the coefficients weights of the FIR filter to reduce the position error signal, the filter coefficient adaptation circuit responding to a characteristic of the acceleration signal to regulate a rate of change at which the coefficients weights are changed to track changes of the acceleration signal; and a head actuator that responds to the feed-forward signal to control head position to counteract disturbances to head position caused by the vibration.
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Specification