16 research outputs found
A superconducting-nanowire 3-terminal electronic device
In existing superconducting electronic systems, Josephson junctions play a
central role in processing and transmitting small-amplitude electrical signals.
However, Josephson-junction-based devices have a number of limitations
including: (1) sensitivity to magnetic fields, (2) limited gain, (3) inability
to drive large impedances, and (4) difficulty in controlling the junction
critical current (which depends sensitively on sub-Angstrom-scale thickness
variation of the tunneling barrier). Here we present a nanowire-based
superconducting electronic device, which we call the nanocryotron (nTron), that
does not rely on Josephson junctions and can be patterned from a single thin
film of superconducting material with conventional electron-beam lithography.
The nTron is a 3-terminal, T-shaped planar device with a gain of ~20 that is
capable of driving impedances of more than 100 k{\Omega}, and operates in
typical ambient magnetic fields at temperatures of 4.2K. The device uses a
localized, Joule-heated hotspot formed in the gate to modulate current flow in
a perpendicular superconducting channel. We have characterized the nTron,
matched it to a theoretical framework, and applied it both as a digital logic
element in a half-adder circuit, and as a digital amplifier for superconducting
nanowire single-photon detectors pulses. The nTron has immediate applications
in classical and quantum communications, photon sensing and astronomy, and its
performance characteristics make it compatible with existing superconducting
technologies. Furthermore, because the hotspot effect occurs in all known
superconductors, we expect the design to be extensible to other materials,
providing a path to digital logic, switching, and amplification in
high-temperature superconductors
Spaceborne memory organization Interim report
Associative memory applications in unmanned space vehicle
Spaceborne memory organization, phase 1 Final report
Application of associative memories to data processing for future space vehicle
Superconducting Heater Cryotron-Based Reconfigurable Logic Towards Cryogenic IC Camouflaging
Superconducting electronics are among the most promising alternatives to
conventional CMOS technology thanks to the ultra-fast speed and ultra-high
energy efficiency of the superconducting devices. Having a cryogenic control
processor is also a crucial requirement for scaling the existing quantum
computers up to thousands of qubits. Despite showing outstanding speed and
energy efficiency, Josephson junction-based circuits suffer from several
challenges such as flux trapping leading to limited scalability, difficulty in
driving high impedances, and so on. Three-terminal cryotron devices have been
proposed to solve these issues which can drive high impedances (>100 k{\Omega})
and are free from any flux trapping issue. In this work, we develop a
reconfigurable logic circuit using a heater cryotron (hTron). In conventional
approaches, the number of devices to perform a logic operation typically
increases with the number of inputs. However, here, we demonstrate a single
hTron device-based logic circuit that can be reconfigured to perform 1-input
copy and NOT, 2-input AND and OR, and 3-input majority logic operations by
choosing suitable biasing conditions. Consequently, we can perform any
processing task with a much smaller number of devices. Also, since we can
perform different logic operations with the same circuit (same layout), we can
develop a camouflaged system where all the logic gates will have the same
layout. Therefore, this proposed circuit will ensure enhanced hardware security
against reverse engineering attacks.Comment: 12 pages, 5 figure
Microelectronic elements applied to the design of digital computer
Call number: LD2668 .R4 1967 P3
Roving vehicle motion control Quarterly report, 1 Mar. - 31 May 1967
System and subsystem requirements for remote control of roving space vehicle motio
Satellite on-board processing for earth resources data
Results of a survey of earth resources user applications and their data requirements, earth resources multispectral scanner sensor technology, and preprocessing algorithms for correcting the sensor outputs and for data bulk reduction are presented along with a candidate data format. Computational requirements required to implement the data analysis algorithms are included along with a review of computer architectures and organizations. Computer architectures capable of handling the algorithm computational requirements are suggested and the environmental effects of an on-board processor discussed. By relating performance parameters to the system requirements of each of the user requirements the feasibility of on-board processing is determined for each user. A tradeoff analysis is performed to determine the sensitivity of results to each of the system parameters. Significant results and conclusions are discussed, and recommendations are presented
Transistorized Digital Computer with Both Real and Stored Time Analog Readout of Information - for Use in Deep Space Investigations of Micrometeor Phenomena
Electrical Engineerin
Recommended from our members
Principles of logic design
This study involves logic design and switching theory, in particular their practical application to the logic design and understanding of digital machines. Digital machines, of course, play an extremely important role in that large class of machines known as digital computers. But they also play an important role in many other kinds of practical devices important in the design of communications systems, digital control systems, counters, registers, digital meters, and so on.
The basic content of switching theory is very simple. It embodies that body of machines and machine behavior that can be realized with "switches", things that are either "on" or "off", and nothing, really, could be much simpler than that. Of course the world is really comprised of very many complex structures which are really composed of exceedingly simple lesser structures, so that we really shouldn't be too surprised that even though the elements of switching theory are quite simple, their consequences are not necessarily so.
The goals of our study are several, and include at least the following:
1) to develop some understanding and capability in using the techniques, design procedures, and models that have been developed for understanding and designing digital networks;
2) to explore in some modest detail the kinds of questions with which logic designers and practitioners concern themselves;
3) to develop an appreciation for the tremendous variation possible in digital design requirements and specifications, i. e,, for the complexity of the 'finite' digital problem, and hence an understanding of the need for systematic design techniques by which to attack such problems;
4) to gain some practice with the fundamental tools and techniques of logic design I so that the reader can adapt the techniques to the "new" problem presented by his own particular design constraints; and
5) to provide an introduction to the literature so that the discerning student can, in the future, dip into the ever growing literature in the field, and find it to some degree comprehensible, and advantageous to use