Browse Prior Art Database

Skew Error Correction

IP.com Disclosure Number: IPCOM000091701D
Original Publication Date: 1968-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Roark, CS: AUTHOR [+2]

Abstract

In magnetic tape storage unit operation, information can be recovered which is normally lost because of excessive skew of the information pattern with respect to the reading apparatus. This circuit increases reliability by providing a longer than normal character gate channel for each information track in combination with the dual sensitivity channels usually used.

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Skew Error Correction

In magnetic tape storage unit operation, information can be recovered which is normally lost because of excessive skew of the information pattern with respect to the reading apparatus. This circuit increases reliability by providing a longer than normal character gate channel for each information track in combination with the dual sensitivity channels usually used.

The arrangement for one bit-track of a multibit system is shown. Information signals, detected and decoded as necessary, are supplied to amplifiers 1 and 2 for two sensitivity channels A and B. Channel A is the high-clip channel and is set to pass signals exceeding a given level, e.g., 35% of standard. Channel B is set to pass lower level signals, e.g., 20% of standard. Amplifiers 1 and 2 supply data signals to bit registers 3 and 4, respectively, which form portions of the skew register for the two sensitivity channels. As in the conventional dual-channel system, the contents of the several A channel bit registers are parity checked in A channel vertical redundancy check circuit 5. If no parity error exists, one gate leg of And 6 is conditioned by Error line 7 to gate the contents of register 3 to a character register for further processing. Error line 8 from VRC circuit 5 is not conditioned in this event and output And 9 of B channel register 4 is closed.

If a parity error exists in the A channel, the cause can be due to a partial signal dropout which could be detected by the lower clip level of channel B. Accordingly, an Error indication on line 8 conditions And 9...