Browse Prior Art Database

Programmed Skew Adjusting Procedure

IP.com Disclosure Number: IPCOM000077508D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Sorenson, WD: AUTHOR [+2]

Abstract

The master skew tape of Fig. 1 consists of magnetic bars and nonmagnetic spaces. The bars 11 and spaces 12 are equal in size so that a square-wave output may be obtained (Fig. 2) from each read head.

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Programmed Skew Adjusting Procedure

The master skew tape of Fig. 1 consists of magnetic bars and nonmagnetic spaces. The bars 11 and spaces 12 are equal in size so that a square-wave output may be obtained (Fig. 2) from each read head.

For optimum operation the read head assembly should be aligned perpendicular to the tape, as indicated by center line C1. In actual practice, the head assembly sometimes may become skewed as indicated by center lines C2 and/or C3.

The disclosed technique provides a method for adjusting the read head assembly to the C1 alignment using the machine display instead of an oscilloscope.

In the environment of a tape drive using a 100 microsecond square wave, reference is made to Fig. 3, wherein the output from track A is sampled at a four microsecond rate (51) until the output changes from one to zero. At this point, a 166 microsecond delay is initiated following which tracks A, B, and N will be read and placed into core memory every four microseconds (52) for 17 bytes.

In a machine having a four character display wherein each contains seven light-emitting diode (LED) segments which may be selectively energized to outline the desired character, such individual segments may be utilized to provide a visible output of the sampled conditions. Other machines may have a CRT or printer or other output which may be used for this purpose. Referring to Fig. 4, the output from track A is examined and the point 21 where the output goes from one to zero is used as the reference point. This reference point will not be displayed, but will be assumed to be midway between the second and third characters o...