Browse Prior Art Database

Pulse Train Generation With Latching Logic Gates

IP.com Disclosure Number: IPCOM000088166D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Herrell, DJ: AUTHOR

Abstract

For the control of inverters within combinatorial latching logic and for the generation of precisely timed data signals, a series of repetitive pulses of a nonlatching character is required. For example, with an interdigitated double stream of such pulses feeding a latching interferometer logic AND gate chain, the required logic level pulses can be generated as shown in Fig. 1.

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 66% of the total text.

Page 1 of 2

Pulse Train Generation With Latching Logic Gates

For the control of inverters within combinatorial latching logic and for the generation of precisely timed data signals, a series of repetitive pulses of a nonlatching character is required. For example, with an interdigitated double stream of such pulses feeding a latching interferometer logic AND gate chain, the required logic level pulses can be generated as shown in Fig. 1.

A stream of pulses such as A or B can be generated using a multi-Josephson junction chain in parallel with a resistor R (Fig. 2), where R is small compared to the subgap resistance R(j) of an individual junction. When a supply current ramp I is applied to the circuit of Fig. 2, all the supply flows through the junction chain until a first device J1 switches and nearly all the supply current is shunted into the load. The current in the junction chain remains very low until the gap characteristic of junction J1 is reached. The voltage across resistor R is then held at 2delta/e and the current once again builds up in the junction chain until a second junction J2 switches.

This action repeats for as many Josephson junctions as there are in the chain. The current waveforms I, I(1) and I(2) are shown schematically in Fig. 3.

The spacing of the pulses depends on the exact distribution of the I(m) (O)'s of the junctions within the chain and the risetime of the supply current I. To a first approximation, assuming a linear ramp with a rate of rise of...