Semiconductors & ICs

Digital Synchronizer Without Metastability

A proposed design for a digital synchronizing circuit would eliminate metastability that plagues flip-flop circuits in digital input/output interfaces. This metastability is associated with sampling, by use of flip-flops, of an external signal that is asynchronous with a clock signal that drives the flip-flops: it is a temporary flip-flop failure that can occur when a rising or falling edge of an asynchronous signal occurs during the setup and/or hold time of a flip-flop.

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Efficient Multiplexer FPGA Block Structures Based on G4FETs

Fewer G4FETs than conventional transistors would be needed to implement multiplexers. Generic structures have been conceived for multiplexer blocks to be implemented in field-programmable gate arrays (FPGAs) based on four-gate field-effect transistors (G4FETs). This concept is a contribution to the continuing development of digital logic circuits based on G4FETs and serves as a further demonstration that logic circuits based on G4FETs could be more efficient (in the sense that they could contain fewer transistors), relative to functionally equivalent logic circuits based on conventional transistors.

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VLSI Microsystem for Rapid Bioinformatic Pattern Recognition

Rapid processing is made possible by a massively parallel neural-computing architecture. A system comprising very-large-scale integrated (VLSI) circuits is being developed as a means of bioinformatics-oriented analysis and recognition of patterns of fluorescence generated in a microarray in an advanced, highly miniaturized, portable genetic-expression- assay instrument. Such an instrument implements an on-chip combination of polymerase chain reactions and electrochemical transduction for amplification and detection of deoxyribonucleic acid (DNA).

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Low-Noise Amplifier for 100 to 180 GHz

Noise temperature is lower than in the prior state of the art. A three-stage monolithic millimeter-wave integrated-circuit (MMIC) amplifier designed to exhibit low noise in operation at frequencies from about 100 to somewhat above 180 GHz has been built and tested. This is a prototype of broadband amplifiers that have potential utility in diverse applications, including measurement of atmospheric temperature and humidity and millimeter-wave imaging for inspecting contents of opaque containers.

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T/R Multi-Chip MMIC Modules for 150 GHz

A transmitting gain of 14 dB at 150 GHz has been demonstrated. Modules containing multiple monolithic microwave integrated-circuit (MMIC) chips have been built as prototypes of transmitting/receiving (T/R) modules for millimeter-wavelength radar systems, including phased-array radar systems to be used for diverse purposes that could include guidance and avoidance of hazards for landing spacecraft, imaging systems for detecting hidden weapons, and hazard-avoidance systems for automobiles. Whereas prior landing radar systems have operated at frequencies around 35 GHz, the integrated circuits in this module operate in a frequency band centered at about 150 GHz. The higher frequency (and, hence, shorter wavelength), is expected to make it possible to obtain finer spatial resolution while also using smaller antennas and thereby reducing the sizes and masses of the affected systems.

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Some Improvements in Utilization of Flash Memory Devices

Two developments improve the utilization of flash memory devices in the face of the following limitations: (1) a flash write element (page) differs in size from a flash erase element (block), (2) a block must be erased before its is rewritten, (3) lifetime of a flash memory is typically limited to about 1,000,000 erases, (4) as many as 2 percent of the blocks of a given device may fail before the expected end of its life, and (5) to ensure reliability of reading and writing, power must not be interrupted during minimum specified reading and writing times.

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GPS/MEMS IMU/Microprocessor Board for Navigation

A miniaturized instrumentation package comprising a (1) Global Positioning System (GPS) receiver, (2) an inertial measurement unit (IMU) consisting largely of surface-micromachined sensors of the microelectro-mechanical systems (MEMS) type, and (3) a microprocessor, all residing on a single circuit board, is part of the navigation system of a compact robotic spacecraft intended to be released from a larger spacecraft [e.g., the International Space Station (ISS)] for exterior visual inspection of the larger spacecraft. Variants of the package may also be useful in terrestrial collision-detection and -avoidance applications.

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