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High Density Recording Technique

IP.com Disclosure Number: IPCOM000094187D
Original Publication Date: 1966-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Morrison, JR: AUTHOR [+3]

Abstract

A substantial increase in the density of recording over other techniques is accomplished using a modified sawtooth waveform for writing the information. The increase occurs because of the relative orientations of the magnetic poles for the adjacent bits of information.

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High Density Recording Technique

A substantial increase in the density of recording over other techniques is accomplished using a modified sawtooth waveform for writing the information. The increase occurs because of the relative orientations of the magnetic poles for the adjacent bits of information.

The write waveform is a modified sawtooth wave having a positive excursion from an equilibrium condition to record a binary 1 and a negative excursion to record a binary 0. The transition from the equilibrium condition occurs in a very small period of time. The return to the equilibrium condition occurs over an extended period of time to provide the sawtooth portion of the waveform. The resultant magnetic pole distribution on the recording medium exhibits considerably less demagnetizing effects than those achieved using other types of recording waveforms. This effect occurs since the magnetic poles of one information bit on the medium are spread out and have less of an effect on the poles of the adjoining information bits.

Detection reliability is ordinarily a severe problem as the density of recording exceeds 10,000 bits per inch. When the modified saw-tooth waveform is employed for writing in this recording method, the detection problem is avoided. Both positive and negative excursions are detected in the read waveform, indicating the recorded 1's and 0's.

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