Detection and measurement of head disc interference using read b

Details Detection and measurement of head disc interference using read b Detection and measurement of head disc interference using read b

1997-09-30

1999-12-28

Strecker, Gerard

Electricity: measuring and testing

Magnetic

Magnetic information storage element testing

360 31, 369 55, G11B 5455, G11B 2736, G01R 3312, G01H 1700

Patent

active

060086408

ABSTRACT:
A method and apparatus for detecting and measuring head-disc interference, in a disc drive, for the purpose of taking preventative and corrective measures, to prevent disastrous head crashes and permanent data loss, is disclosed. The method and apparatus detect and measure the frequency modulation (FM) of a read back signal generated by longitudinal head oscillation, as a result of head-disc interference. The longitudinal head oscillation can be ascribed to the non-linear response of the air bearing supporting the head on the disk surface. The response exhibits a vibration frequency in the head in the 100 to 250 kHz range. The more severe the interference contact is, the higher the vibration amplitude which then leads to read signal frequency modulation (FM). A method and apparatus is described to detect the FM modulation and thereby to detect the severity of the head disk interference for proximity recording. A pre-written pattern on the disk can be read back to monitor for FM, and a modulation index, .beta., is generated by observing the resulting signal. By demodulating the modulated read back signal, the severity of the interference can be determined. This method can be applied as a diagnostic tool at a manufacturing test station, in a laboratory test setup, or in a disk drive using the disk drive's own read/write channel electronics, without the need for an external sensor.

REFERENCES:
patent: 5594595 (1997-01-01), Zhu
patent: 5742446 (1998-04-01), Tian et al.
patent: 5838153 (1998-11-01), Inbar

Affiliated with

Also associated with

Rating

Detection and measurement of head disc interference using read b does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Detection and measurement of head disc interference using read b, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detection and measurement of head disc interference using read b will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2384794