Browse Prior Art Database

Head/Disk Assembly Tester Autocalibrator

IP.com Disclosure Number: IPCOM000042027D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Davenport, JS: AUTHOR [+2]

Abstract

In the manufacture of disk files, the magnetic disks are subjected to a surface analysis test to insure that the storage characteristics of the disk meet predetermined specifications. One such test involves comparing the amplitude of the read signal from data stored on a disk with a reference voltage, called clip level. The clip level signal is generated by a digital-to-analog converter (DAC) which is controlled to provide a signal that a known percentage of the nominal signal amplitude expected. The compare test is a go/no-go type test. In order to insure that the tester is operating according to specifications, a "standard" disk surface is tested and the tester is recalibrated. These calibration runs are costly and complex.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 56% of the total text.

Page 1 of 2

Head/Disk Assembly Tester Autocalibrator

In the manufacture of disk files, the magnetic disks are subjected to a surface analysis test to insure that the storage characteristics of the disk meet predetermined specifications. One such test involves comparing the amplitude of the read signal from data stored on a disk with a reference voltage, called clip level. The clip level signal is generated by a digital-to-analog converter (DAC) which is controlled to provide a signal that a known percentage of the nominal signal amplitude expected. The compare test is a go/no-go type test. In order to insure that the tester is operating according to specifications, a "standard" disk surface is tested and the tester is recalibrated. These calibration runs are costly and complex. The figure shows an arrangement in which the tester is provided with a self-calibration system that becomes part of the surface test routine and precedes each test, thereby eliminating the need for providing reference runs and recalibration by a standard. The autocalibration system, shown in the figure, includes an input terminal 9 and block 10, which represents all hardware preceding the amplitude detection circuits. The autocalibration system further includes comparator 11, DAC 12, DAC modifier 13, a controller 14, which has one input terminal 15 connected to the output 16 of the amplitude detection circuits and another input 17 supplied from the program block 18. Input 20 of the comparator 11 is co...