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Pulse Position Recording

IP.com Disclosure Number: IPCOM000077785D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Viele, L: AUTHOR

Abstract

Information is written by a transducer on magnetic media using pulse-position modulation.

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Pulse Position Recording

Information is written by a transducer on magnetic media using pulse- position modulation.

As is well known, data may be represented by positive and negative transitions for purposes of writing information on magnetic media. The IBM Technical Disclosure Bulletin article entitled "Pulsed-Field Magnetic Recording" by F. Ainscow, published November, 1970, Vol. 13 No. 6 page 1613, describes write current related to the data as shown in Figs. 1 and 2. Fig. 3 shows a variation wherein a positive and negative pair of signals correspond to each data transition. Thus, the first positive/ negative pair in Fig. 3 represents the positive data transition of Fig. 1.

Pulse-position modulation of only one of the pulses in a pair of pulses preserves timing relationships while conveying information for recording. In Fig. 4, the pulses of Fig. 3 have been preserved as identical positive/negative pairs for each data transition, and the negative pulses have been moved from their normal position to represent transition direction. For example, a positive transition is represented by a lagging negative pulse, and a negative transition is represented by a leading negative pulse. If desired, the functions of the positive and negative pulses could be reversed.

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