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Excessive Skew Error Correction

IP.com Disclosure Number: IPCOM000095082D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Morphet, JC: AUTHOR

Abstract

The system corrects any error caused by excessive skew when reading magnetic tape having a plurality of tracks A... N. The output of readhead assembly 21 is provided via lines 22A...22N to both track excessive skew detector 10 and bit dropout detectors 12A... 12N. Each detector 12 detects if each bit from a respective tape track is less than a predetermined level, in which case it is considered a dropout. A signal is provided on a respective detector output line 13A... 13N. Detector 10 determines which track or tracks exceed the normal skew accommodation of the system. It Or 14A receives input leads 11A and 13A. Or 14N receives inputs 11N and 13N. Hence, the output of Or 14A indicates if there is any error in track A of tape 20. Such occurs regardless if the error is caused by dropout or by excessive skew of track A.

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Excessive Skew Error Correction

The system corrects any error caused by excessive skew when reading magnetic tape having a plurality of tracks A... N. The output of readhead assembly 21 is provided via lines 22A...22N to both track excessive skew detector 10 and bit dropout detectors 12A... 12N. Each detector 12 detects if each bit from a respective tape track is less than a predetermined level, in which case it is considered a dropout. A signal is provided on a respective detector output line 13A... 13N. Detector 10 determines which track or tracks exceed the normal skew accommodation of the system. It Or 14A receives input leads 11A and 13A. Or 14N receives inputs 11N and 13N. Hence, the output of Or 14A indicates if there is any error in track A of tape 20. Such occurs regardless if the error is caused by dropout or by excessive skew of track A. Likewise, the output of any of the other Or's 14 indicates whether or not a Or 14A receives input leads 11A and 13A. Or 14N receives inputs 11N and 13N. Hence, the output of Or 14A indicates if there is any error in track A of tape
20. Such occurs regardless if the error is caused by dropout or by excessive skew of track A. Likewise, the output of any of the other Or's 14 indicates whether or not a particular track has an error either by dropout or excessive skew.

Error correction circuit 16 corrects the error in any one or more tape tracks having an error indication from one or more Or's 14.

The detailed form of corre...