Browse Prior Art Database

Josephson Oscillator

IP.com Disclosure Number: IPCOM000089397D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Chaudhari, P: AUTHOR [+2]

Abstract

Josephson oscillators are expected to be useful in communications applications and as generators of clock pulses, for example, in integrated Josephson circuits. This article discloses an oscillator which, in addition to providing the basic oscillator function at high frequencies, can be easily fabricated and has an adjustable output frequency.

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Josephson Oscillator

Josephson oscillators are expected to be useful in communications applications and as generators of clock pulses, for example, in integrated Josephson circuits. This article discloses an oscillator which, in addition to providing the basic oscillator function at high frequencies, can be easily fabricated and has an adjustable output frequency.

The basic oscillator is shown in the above figure. The circuit includes a plurality of Josephson devices J1, J2, J3, connected in parallel, to which the current I(c) is applied. This current is fed via control magnetically coupled relationship with these junctions. The critical field H(c), developed by the current I(c) in line A, switches the junctions J1-J3 to the voltage state. Thus, the current flow in the circuit is reduced to zero. This, of course, means that H(c) also reduces to zero. At this point, junctions J1-J3 switch on again, establishing the oscillatory feature of the circuit. Resonant cavities, strip lines, antenna arrays and the like can be used to enhance the oscillations. Several junctions or devices may be used to ensure that enough field is present to switch each of the junctions while not enough may be present for a single device. Of course, a greater number of devices than three can be used.

The multiplicity of devices provides a surprising and unexpected result. The number of devices controls the total R, L, and C of the circuit. Each additional device, therefore, will change the c...