Browse Prior Art Database

Adjusting Mechanical and Electrical Skew

IP.com Disclosure Number: IPCOM000077507D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Wojtczak, EP: AUTHOR

Abstract

To effect skew adjustment on a Phase Encoded (PE) write-only tape deck assembly, it is necessary to observe three data tracks. Track 4, the marginal track closest the pivot point for the write head assembly, may be considered the track about which the head assembly pivots and serves as the reference track. The second track observed is track 6 immediately adjacent track 4 and the third is track 5, the track farthest from the pivot.

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Adjusting Mechanical and Electrical Skew

To effect skew adjustment on a Phase Encoded (PE) write-only tape deck assembly, it is necessary to observe three data tracks. Track 4, the marginal track closest the pivot point for the write head assembly, may be considered the track about which the head assembly pivots and serves as the reference track. The second track observed is track 6 immediately adjacent track 4 and the third is track 5, the track farthest from the pivot.

Mechanical head alignment may be accomplished using a master skew tape and the circuit illustrated. The head is mechanically adjusted until light-emitting diode (LED) 3 and LED 4 are actuated simultaneously. The duration of single- shot (SS) 6 and that of SS7 (here 0.4 an 1.1 micro seconds, respectively) are selected such that polarity holds (PH) 9 and 10 cause simultaneous illumination of LEDs 3 and 4, when activated by signals from a common data byte. When this is achieved, a further adjustment is made to cause LED 5 to also be illuminated. The duration of SS8 (here shown as 7ms), in conjunction with the duration of SS6, assures that the head is aligned within the required tolerance when the three LEDs are simultaneously illuminated.

By permitting one of the inputs, such as data track 5 to be jumpered, electrical read and write skew correction is possible.

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