Browse Prior Art Database

Automatic Skew Adjustment

IP.com Disclosure Number: IPCOM000078327D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Birdsall, IP: AUTHOR

Abstract

The trailing edges of read signals for all the tracks of a tape are lined up by automatically adjusting the timing of deskewing single-shots in a tape unit.

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Automatic Skew Adjustment

The trailing edges of read signals for all the tracks of a tape are lined up by automatically adjusting the timing of deskewing single-shots in a tape unit.

The deskewing single-shots pass signals from read heads to read circuits, not shown, as timed width pulses. A hand-held motor screwdriver is held against the skew adjustment potentiometer shaft of each single-shot in turn, to adjust each single-shot relative to a reference single-shot until all the output pulses are lined up with the reference output pulse. The screwdriver is operated under the control of a circuit connected to selected test points (TP) of the tape unit. Single- shots SS1 and SS2 initiate timed pulses for trailing edges of tape unit pulses.

The reference single-shot is chosen as the one with the most lagging output pulse trailing edge. For example, if the reference track TR pulse leads the selected track TS pulse, the single-shot timing for the track TS must be shortened by turning its skew adjustment counterclockwise. This occurs when flip-flop FF1 is set by AND circuit 61. Similarly, FF2 is set by 62, when TR lags TS, to turn the adjustment clockwise. No adjustment is made when TR and TS are equal.

This technique is equally applicable to other single-shots, not shown, in the read path of tape drives and also to disc drives.

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