Browse Prior Art Database

Cryotron Digital/Analog Converter

IP.com Disclosure Number: IPCOM000079229D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Landman, BS: AUTHOR

Abstract

Use of Josephson tunneling gates to implement a digital to analog (D/A) converter is proposed, wherein gap voltages of proper switched stacks of such gates are summed.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Cryotron Digital/Analog Converter

Use of Josephson tunneling gates to implement a digital to analog (D/A) converter is proposed, wherein gap voltages of proper switched stacks of such gates are summed.

Illustrated is a number of Josephson tunneling gates 10-22.

Each gate is serially connected to and biased by a current source I1.

Digital inputs X generate control currents Ic. Each input control current Ic(1) controls 2/i/ junctions (Rates). Thus, the voltages produced by these junctions are summed by wiring the junctions into a series stack. If the bottom of the stack is grounded, then the voltage Vo at the top of the stack is given by

(Image Omitted)

where X(i) denotes the logical state of the corresponding control current Ic(i). If vector W = (X(n)... X(2)X(1)X(0)), then Vo approximates the numerical value of w treated as a binary number, thus effectuating D/A conversion. A reset, obtained by lowering the bias current I1 momentarily, is required before converting the next word.

Variations may be obtained by varying the number of gates associated with each input X and, if desired, an analog output proportional to the sum or difference of two binary words may be obtained, by providing two stacks of the type described and stacking them to provide sum or difference.

1

Page 2 of 2

2

[This page contains 4 pictures or other non-text objects]