Electrical/​Electronics

A photodetector circuit has been built for use in the receiver portion of a continuous-wave infrared Doppler lidar system for atmospheric research. As in nearly all Doppler lidar systems, the detection of the return signal in this system involves heterodyning, in a photodetector, with a...

A lidar apparatus called a microaltimeter has been proposed for use aboard a spacecraft in orbit around the Earth for mapping land and sea surfaces, including such features of special interest as ice, tree canopies, and flood plains. The microaltimeter is short for "microlaser altimeter" and...

Ignitor and keeper power supplies have been developed specifically for a Hall-effect thruster with a cold cathode. Prior to the development of these power supplies, difficulties had been observed in the operation of cold-cathode Hall thrusters; in particular, they did not start reliably...

Range Safety Officers (RSOs) are used by NASA and other government agencies to assure protection of life and property during launch operations. The current decision-making system used by the RSOs at NASA Wallops Flight Facility (WFF) and the National Ranges, including the Eastern Range (ER) and Western...

Experiments have shown that a substrate can be patterned with submicron features by the following procedure:

An advanced technique of deep reactive-ion etching (DRIE) has been developed for fabricating smooth vertical walls in silicon wafers. These walls are suitable for use as bounding surfaces of optical waveguides in photonic and optoelectronic devices. The roughness of a typical 8-µm-high...

A previously developed apparatus that tracks the orientation of the human eye has been modified to make it less susceptible to error induced by ambient infrared light. The apparatus is a commercial product intended primarily for use as a computer-control interface for a person who is physically unable to use a...

Neural networks of a proposed type would be formed with computational units called "neuromorphs" attached in a locally connected array. These neural networks would achieve pattern recognition invariant under rotation and translation by exploiting a combination of network symmetry and...