Browse Prior Art Database

DC Ripple Erase

IP.com Disclosure Number: IPCOM000085416D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Boni, RL: AUTHOR [+2]

Abstract

Described is a DC erase scheme, wherein the head inductance provides energy to maintain an effective DC erase current through itself. Due to the fact that the erase head inductance is not a hindrance, as in high-frequency erase schemes, more turns can be wound on the head and the current necessary to erase effectively can be smaller.

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DC Ripple Erase

Described is a DC erase scheme, wherein the head inductance provides energy to maintain an effective DC erase current through itself. Due to the fact that the erase head inductance is not a hindrance, as in high-frequency erase schemes, more turns can be wound on the head and the current necessary to erase effectively can be smaller.

As shown in Fig. 1, the erase driver current output is asymmetrical. During the +I portion, the arrows depict current flow in the erase head.

As is shown in Fig. 2, during the -I portion of the driver current, the direction of current flow is reversed. Due to the blocking effect of blocking diode D1, loop A of recording means 10 is void of current. Simultaneously, loop B of recording means 10 has current flowing in a direction identical to current flow during the positive cycle of the driver current. The flow of current shown in loop B of Fig. 2 is derived from the erase head inductance.

In Fig. 3, several cycles of erase head current are shown. When ripple on the erase head current is above the steady DC current required for effective erase, no trace of the erase frequency is left on tape.

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