Dynamic magnetic information storage or retrieval – Monitoring or testing the progress of recording
Patent
1989-10-26
1992-12-15
Sniezek, Andrew L.
Dynamic magnetic information storage or retrieval
Monitoring or testing the progress of recording
360 46, G11B 2736
Patent
active
051722801
ABSTRACT:
An apparatus and a method for calibrating the write current applied to a write head (110, 114) in a tape drive (100) finds the peak value of the write current applied to the tape head (110, 114) (i.e., the write current value providing the maximum read voltage amplitude on a tape (104)) by indirectly measuring the voltage sensed by a read head (112, 115). The apparatus includes a digital write current control circuit (170, 160) that applies a write current having a magnitude responsive to a digital write current value. An amplifier (190) in a read circuit (180, 182, 184, 190, 196) has a gain responsive to a digital read gain value. The method includes the steps of sampling the output of a pattern detector (146) (e.g., a gap detector) as the digital read gain value is adjusted for each of a number of digital write current data values applied to the write current control circuit (170, 160). The digital read gain value is adjusted to provide a predetermined range of the number of samples wherein the pattern corresponds to a predetermined pattern. The digital read gain value for each digital write current value is inversely related to the amplitude of the signal recorded on the tape (104). The sampled digital read voltage gain values are then stored. The digital write current value corresponding to the minimum stored digital read gain value also corresponds to the peak value of the actual write current. The digital write current value corresponding to the minimum digital read voltage gain value is then selected and stored as the calibrated digital write current.
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Streaming, Copyright.COPYRGT. 1982, Archive Corporation, ISBN O-9608810-O-X, Library of Congress Catalog Number: 82-072125, pp. 5-1 through 5-21.
Quintus John J.
Sheehan Michael S.
Vu Tuong M.
Archive Corporation
Sniezek Andrew L.
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