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Digital to Analog Converter

IP.com Disclosure Number: IPCOM000081535D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Fang, FF: AUTHOR

Abstract

IBM Technical Disclosure Bulletin, Vol. 16, No. 1, June 1973, pp1-2, in an article entitled "Cryotron Digital/Analog Converter" by B. S. Landman, shows a digital-to-analog converter incorporating a series chain of Josephson junctions, wherein the number of Josephson junctions switched are related to the value of a digital signal on control lines associated with the Josephson junctions. An analog signal which is determined by the number of Josephson junctions switched, represents the input digital signals in an analog voltage form.

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Digital to Analog Converter

IBM Technical Disclosure Bulletin, Vol. 16, No. 1, June 1973, pp1-2, in an article entitled "Cryotron Digital/Analog Converter" by B. S. Landman, shows a digital-to-analog converter incorporating a series chain of Josephson junctions, wherein the number of Josephson junctions switched are related to the value of a digital signal on control lines associated with the Josephson junctions. An analog signal which is determined by the number of Josephson junctions switched, represents the input digital signals in an analog voltage form.

In the arrangement shown, as soon as the gate current is removed the analog information is lost. Ordinarily, this must be done to convert the next indigital signal to analog form. The operation of such an arrangement is, therefore, substantially discontinuous.

The figure provides an arrangement whereby there is no interruption of output during the conversion of the next incoming digital sample. Thus, Josephson junctions J2, J1 and/or J0 are switched to their resistive state, depending on which of the digital inputs is activated.

When the Josephson junctions are switched, a loop L2, L1 and/or L0 receives current diverted from the switched Josephson junctions which, in turn, switches Josephson junctions J2', J1' and/or J0' because the loops L2, L1 and/or L0 act as control lines for the second series chain of Josephson devices. Thus, two chains of junctions are employed with the first output driving another iden...