Engineering topics

Lee, Jun-Ji

Publications and source records attributed to Lee, Jun-Ji.

5 records

NASA NTRS1989

VLSI Universal Noiseless Coder

Proposed universal noiseless coder (UNC) compresses stream of data signals for efficient transmission in channel of limited bandwidth. Noiseless in sense original data completely recoverable from output code. System built as very-large-scale integrated (VLSI) circuit, compressing data in real time at input rates as high as 24 Mb/s, and possibly faster, depending on specific design. Approach yields small, lightweight system operating reliably and consuming little power. Constructed as single, compact, low-power VLSI circuit chip. Design of VLSI circuit chip made specific to code algorithms. Entire UNC fabricated in single chip, worst-case power dissipation less than 1 W.

Rice, Robert F.↗

NASA NTRS1989

Noiseless Coding Of Magnetometer Signals

Report discusses application of noiseless data-compression coding to digitized readings of spaceborne magnetometers for transmission back to Earth. Objective of such coding to increase efficiency by decreasing rate of transmission without sacrificing integrity of data. Adaptive coding compresses data by factors ranging from 2 to 6.

Rice, Robert F.↗

NASA NTRS1988

A VLSI design for universal noiseless coding

The practical, noiseless and efficient data-compression technique presented involves a conceptual VLSI design which is capable of meeting real-time processing rates and meets low-power, low-weight, and small-volume requirements. This form of data compression is applicable to image data compression aboard future low-budget spaceflight missions, for such instruments as visual-IR mapping spectrometers and high-resolution imaging spectrometers.

Lee, Jun-Ji↗

NASA NTRS1987

Noiseless coding for the magnetometer

Future unmanned space missions will continue to seek a full understanding of magnetic fields throughout the solar system. Severely constrained data rates during certain portions of these missions could limit the possible science return. This publication investigates the application of universal noiseless coding techniques to more efficiently represent magnetometer data without any loss in data integrity. Performance results indicated that compression factors of 2:1 to 6:1 can be expected. Feasibility for general deep space application was demonstrated by implementing a microprocessor breadboard coder/decoder using the Intel 8086 processor. The Comet Rendezvous Asteroid Flyby mission will incorporate these techniques in a buffer feedback, rate-controlled configuration. The characteristics of this system are discussed.

Rice, Robert F.↗

NASA NTRS1987

Real-time data compressor for Eos-class missions

A conceptual design for a real-time VLSI compressor capable of processing rate up to one gigabit per second is presented. This scheme is capable of providing a three-to-one distortion-free data reduction factor to both the High Resolution Imaging Spectrometer and processed SAR imaging data. The design uses a VLSI parallel/piplined architecture capable of processing at a real time rate. The design consists of a parallel array of VLSI compressor modules. Each module is built on a single customized VLSI chip using existing state-of-the-art semiconductor technology.

Lee, Jun-Ji↗