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Directional Coupling Read Only Storage

IP.com Disclosure Number: IPCOM000094424D
Original Publication Date: 1965-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Lockhart, NF: AUTHOR

Abstract

Entry of data in a read-only memory by directional coupling techniques permits use of the ordinary capacitance of the storage intersection to cancel the 0 signal, thus improving the signal-to-noise ratio.

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Directional Coupling Read Only Storage

Entry of data in a read-only memory by directional coupling techniques permits use of the ordinary capacitance of the storage intersection to cancel the 0 signal, thus improving the signal-to-noise ratio.

The configuration of the storage intersection is calculated to produce capacitively coupled signals and inductively coupled signals of equal value. The capacitively coupled signals are bidirectional in nature. The inductively coupled signals are unidirectional in nature. The capacitively coupled signals can thus be used to enhance or to cancel the inductively coupled signals. The 1 inter section is a configuration in which the capacitively coupled signal and inductively coupled signal add at the sense amplifier end of the wire. The 0 intersection is a configuration in which the capacitively coupled signal and inductively coupled signal cancel at the sense amplifier end of the wire. They add at the other end of the wire but this signal is terminated in a nonreflective termination. The 1 configuration thus provides a signal to the sense amplifier which is the sum of equal capacitively coupled and inductively coupled signals while the 0 configuration provides to the sense amplifier a null signal. This signal is the difference between the capacitively coupled signal and inductively coupled signal which signals effectively cancel. The 1 signal at the sense amplifier thus is a large signal while the 0 signal at the sense amplifier is a very small signal.

In the drawing, storage elements 11...14 are provided with data values through directional coupling of the inductive elements. Elements 11 and 12 are shown in diagram form. Elements 13 and 14 are shown schematically. Each element involves an intersection of a column conductor 15-16 with a row conductor 17-18, which serve, respectively, as sense and word selection conductors. Conductors 17-18 are connected at the left end to word drive circuits 19 and 20, respectively, and at the right ends to ground through resistances 21 and 22, respectively. Resistances 21 and 22 are the characteristic impedances of their related conductors and thus provide nonreflective terminations. Sense conductors 15 and 16 are terminated in resistances 23-26 which are the characteristic impedances of those conduc...