Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Determination Of Skew

IP.com Disclosure Number: IPCOM000097031D
Original Publication Date: 1962-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Chien, TR: AUTHOR [+2]

Abstract

The method detects changes in skew of a magnetic tape corresponding to one or more bits per tape width. It consists of coding the outermost channels of tape with related bit sequences and continuously comparing these sequences. The particular code sequence, used in the outermost channels, depends on the number of bits per tape width change in skew it is desired to detect.

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 74% of the total text.

Page 1 of 2

Determination Of Skew

The method detects changes in skew of a magnetic tape corresponding to one or more bits per tape width. It consists of coding the outermost channels of tape with related bit sequences and continuously comparing these sequences. The particular code sequence, used in the outermost channels, depends on the number of bits per tape width change in skew it is desired to detect.

The circuitry detects a one bit per tape width change in skew. The outermost channels of the tape are recorded with alternate 1's and 0's. The recording in the two channels is such that they agree for zero skew. At the beginning of the record cycle, AND 10 is conditioned by a start to record signal. If, at this time, there is no skew in the tape, the information read on channels 1 and 13 is the same. There is no output from exclusive OR 12. Flip flop 14 is, therefore, not set. So long as there continues to be no skew, OR 16 receives no input. There is no output at the change in skew signal terminal. If, however, at a subsequent time in the record cycle, skew occurs, the information coming in on channels 1 and 13 does not agree and OR 12 generates an output. Since no input is applied to OR 16 by flip flop 14, the output from OR 12 passes through OR 16 and conditioned AND 18 to appear as an output on the change in skew signal terminal.

If, on the other hand, there had initially been a one bit per tape width skew in the tape, the first output signal from OR 12 causes flip flop...