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Nondestructive Readout Memory

IP.com Disclosure Number: IPCOM000074158D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Bertelsen, BI: AUTHOR [+2]

Abstract

This magnetic film memory providing very high signal-to-noise ratios utilizes a conventional dispersion locked mode writing operation, as described in IBM Journal, Vol. 10, No. 1, January 1966, pp.89 to 94, by Kump et al, and a high frequency or microwave absorption read operation. Magnetic film 10, of the type described in the above referenced article, has a magnetic easy axis arranged parallel to the direction of word lines W1, W2, W3 and W4 connected between word pulse and selection circuitry 12 and ground. Bit lines B1, B2, B3 and B4, disposed perpendicular to word lines, carry high frequency or microwave current from high-frequency source and bit selection circuitry 14 to sense amplifier detector 16.

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Nondestructive Readout Memory

This magnetic film memory providing very high signal-to-noise ratios utilizes a conventional dispersion locked mode writing operation, as described in IBM Journal, Vol. 10, No. 1, January 1966, pp.89 to 94, by Kump et al, and a high frequency or microwave absorption read operation. Magnetic film 10, of the type described in the above referenced article, has a magnetic easy axis arranged parallel to the direction of word lines W1, W2, W3 and W4 connected between word pulse and selection circuitry 12 and ground. Bit lines B1, B2, B3 and B4, disposed perpendicular to word lines, carry high frequency or microwave current from high-frequency source and bit selection circuitry 14 to sense amplifier detector 16. Binary information indicative of a 1 is stored along the easy axis of the film and indicative of a 0 is stored perpendicular to the easy axis.

The memory is nondestructively sensed by applying to a selected word line,
e. g., W2, a perturb pulse having an amplitude less than the film locking threshold while the microwave current is being carried by the bit lines B1, B2, B3 and B4. The perturb pulse may have the same polarity as or opposite polarity to the word write pulse. A change in power absorbed by a bit in the selected word, when the perturb pulse is applied, indicating the presence of a 1 bit of information is detected in sense amplifier detector 16 connected to bit lines B1, B2, B3, and B4. The frequency of the high frequency...