Seagate Technology Incorporated

Maxtor Corporation

David Finamore

Curtis W Egan

Michael Dickeson

Farhad Navid

Naveen Viswanath

Methods of tuning a notch filter to remove resonant frequency components from an output signal of a vibration sensor. Some methods according to the invention include exciting the vibration sensor with an excitation signal including energy in a frequency band that may include a resonant frequency of the vibration sensor, measuring the output signal of the vibration sensor in response to the excitation signal, detecting a frequency component of the output signal that corresponds to the resonant frequency of the vibration sensor, and configuring the notch filter to attenuate the detected frequency component. Related disk drives are also disclosed.

Sensor resonant frequency identification and filter tuning

A disk drive can include a data storage disk, a head, an acceleration sensor, and a controller. The head is configured to write data on the disk. The acceleration sensor generates an acceleration signal that is indicative of acceleration of the disk drive. The controller determines when the disk drive is being subjected to a vibration condition determination. The controller can inhibit writing of data through the head onto the disk based on comparison of the acceleration signal to the threshold value.

Controlling a write inhibit threshold based on vibration

Methods and structures for detecting touchdown of the read/write head on its recording surface or for detecting other read signal amplitude modulations as proportional to variance of the value of the read channel variable gain amplifier ('VGA'). Variance in the VGA values caused by the standard feedback control electronics associated therewith is proportional to amplitude modulations of the sensed signal picked up by the read channel (or servo read sensor). These amplitude modulations are, in turn, reflective of flying height of the read/write head as well as generally indicative of other parameters of the read channel operation. Touchdown of the read/write head and other parameters of the disk drive operation may therefore be detected as variances in the VGA control values.

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Louisville, CO, United States of America

David Finamore