Browse Prior Art Database

Magnetic Tape Coding

IP.com Disclosure Number: IPCOM000092415D
Original Publication Date: 1966-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Chesarek, DJ: AUTHOR [+2]

Abstract

A code with implementation for providing accurate positioning of a movable device is shown.

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Magnetic Tape Coding

A code with implementation for providing accurate positioning of a movable device is shown.

A tape containing binary marks associated with location addresses is laid along the path of the device which contains a transducer for reading the marks while traversing the tape. The tape has an A column for 1's and an adjacent B column for 0's. Address information is coded with a mark in the appropriate column and an adjacent space in the other column. A record mark 1, used to designate the end of one address group and the beginning of the next, is coded as two adjacent marks, i.e., a mark in both columns.

The circuitry for interpreting the code includes transducers 1 and 2 for reading the A and B columns of the tape, waveform shaping circuits 3 and 4 for the transducers, counter 5, trigger 6, registers 7 and 8, and appropriate logic. As each mark is read, its binary value is transmitted through Or 9, and either And 10 or 11 to one of the registers. At the same time counter 5 is incremented. Whenever an 1 is recognized, a signal is passed through And 12 which resets counter 5 and flips trigger 6 to select the other register for the new address. At any given time the contents of the previously used register form the high-order portion of the current location address.

The contents of counter 5 form the low-order position of the address. Thus each binary mark serves a dual purpose. It provides both coarse and fine positioning information.

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