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Browse Prior Art Database

Josephson Junction Clock Oscillator

IP.com Disclosure Number: IPCOM000080503D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Klein, M: AUTHOR

Abstract

Present Josephson junction logic schemes require clock signals which are supplied from sources external to the cryogenic system. This has the disadvantages that (a) available pulse sources tend to be slower than the Josephson junction logic speeds, and (b) extra external apparatus and signal cables are needed.

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Josephson Junction Clock Oscillator

Present Josephson junction logic schemes require clock signals which are supplied from sources external to the cryogenic system. This has the disadvantages that (a) available pulse sources tend to be slower than the Josephson junction logic speeds, and (b) extra external apparatus and signal cables are needed.

The following describes a circuit arrangement for generating clock signals within the cryogenic system, using Josephson junction devices with their inherent speed capabilities.

In the figure, a Josephson junction 1 is connected to a terminated transmission line 2. The impedance of transmission line 2 is designed so that with current Iv flowing in a portion of transmission line 2 which is disposed adjacent junction 1, junction 1 recovers from the voltage state without interruption of gate current Ig. Bias current, I(bias), is provided in control line 3 such that with gate current Ig and bias current I(bias), but no current Iv, junction 1 switches to the voltage state.

Assuming that the gate current, I(g), and the bias current, I(bias), are starts to flow in transmission line 2. After a delay determined by the length of transmission line 2, current, Iv, reaches its maximum level and junction 1 switches back to the current state. After a second delay, also determined by transmission line 2, Iv decays and the junction switches to the voltage state. The circuit of the figure, therefore, behaves as a line-controlled oscillator....