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AC Erase for High Density Digital Recording

IP.com Disclosure Number: IPCOM000087988D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Boni, RL: AUTHOR [+2]

Abstract

The figures depict a method and device whereby AC erase is utilized for obliterating previously recorded digital data on a magnetic recording media.

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AC Erase for High Density Digital Recording

The figures depict a method and device whereby AC erase is utilized for obliterating previously recorded digital data on a magnetic recording media.

Fig. 1 shows the relationship between the erase wavelength b and the erase gap length L of the erase head shown in Fig. 2. As can be seen from Fig. 1, the longer the erase gap L relative to the erase signal wavelength b, the more effective is the erase (less data residual). By selecting the gap length to straddle multiples of erase cycle wave-length, a more efficient erase technique is achieved. Also, by selecting the erase wavelength to coincide with data null, readback interference is reduced.

Fig. 2 depicts a circuit configuration which enables the use of the AC erase. The circuit includes an erase driver connected to an erase head via an inductive interface. A capacitor C is connected in series with the erase head. By resonating the erase head inductance (L(H)) with the series capacitor at erase frequency, the voltage requirement of the driver is significantly reduced.

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