Browse Prior Art Database

Modular Tree Decoder

IP.com Disclosure Number: IPCOM000089399D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 38K

Publishing Venue

IBM

Related People

Zappe, HH: AUTHOR

Abstract

This article describes a tree decoder which is modular in character. The modular character of the decoder is achieved by isolating the current flow in any decoder stage to that decoder stage, with coupling between decoder stages being totally magnetic in character.

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Modular Tree Decoder

This article describes a tree decoder which is modular in character. The modular character of the decoder is achieved by isolating the current flow in any decoder stage to that decoder stage, with coupling between decoder stages being totally magnetic in character.

Referring to the figure, a modular cell 1 is shown which includes three devices that are capable of carrying Josephson current, such as an interferometer gate. The three gates include a driver gate J1 which is controlled by the output of a preceding stage or by an input signal applied to a control line 2 which is disposed in electromagnetically coupled relationship with gate J1. Also included are two decoder gates J2, J3 which are controlled by address lines 3,4, respectively. Devices J2, J3 are disposed in branches 5, 6, respectively, which have equal inductance and are connected to a common point 7 via resistors R. Driver gate J1 is connected to branches 5, 6 via a forward inductance L(F), while common point 7 is connected to driver gate J1 via return inductance L(R). Portions 8, 9 of branches 5, 6, respectively, form control lines disposed in electromagnetically coupled relationship with a pair of succeeding driver gates J4, J5, each of which is connected to a modular cell exactly like modular cell 1 just described.

The same elements in the second stage of the modular tree decoder have been assigned the same reference characters. From Fig. 1, it should be clear that each succeeding stage of the decoder contains twice as many modules 1 as its preceding stage. Thus, while only two stages have been shown, it should be clear that, utilizing the arrangement of Fig. 1, one out of four, one out of eight, one out of sixteen, etc., array line drivers, for example, may be selected. Resistor R of modular cell 1 is of such value that its associated driver gate J1, for example, is self-resetting.

In operati...