31 research outputs found
Digital communications techniques Interim report, 15 Sep. 1969 - 15 Feb. 1970
Convolutional codes and recursive signal processing for digital communication
A space communications study Status report, 15 Dec. 1968 - 15 Mar. 1969
Harmonic distortion in frequency demodulator using feedback, delta modulation, recursive signal processing techniques, and multipath fadin
A space communication study Progress report, 15 Sep. 1966 - 15 Mar. 1967
Space communications studies of optimal signal reception, threshold extension, signal detection against noise, channel simulation, and synchronization technique
A space communications study Final report, 15 Sep. 1968 - 15 Sep. 1969
Analog and digital signal reception problems through noisy channels, and computerized digital TV system for space communication
A space communication study Final report, 15 Sep. 1967 - 15 Sep. 1968
Transmitting and receiving analog and digital signals through noisy media - space communications stud
A space communications study Final report, 15 Sep. 1966 - 15 Sep. 1967
Investigation of signal to noise ratios and signal transmission efficiency for space communication system
A Space Communications Study Final Report, Sep. 15, 1965 - Sep. 15, 1966
Reception of frequency modulated signals passed through deterministic and random time-varying channel
Image Processing for Cartographic Applications
The goal of classifying objects of cartographic interest in aerial photographs was approached using techniques from pattern recognition and image processing. Bridge and airport images were chosen as the initial objects of interest and segments of photographs containing them were digitized for the data base. Edge-detection and Hough transform algorithms identified structures as candidate bridges; additional decision logic (using global contrast and other attributes) further reduced the set. Results indicate the feasibility and low computational cost of the approach
Cornerstones of Sampling of Operator Theory
This paper reviews some results on the identifiability of classes of
operators whose Kohn-Nirenberg symbols are band-limited (called band-limited
operators), which we refer to as sampling of operators. We trace the motivation
and history of the subject back to the original work of the third-named author
in the late 1950s and early 1960s, and to the innovations in spread-spectrum
communications that preceded that work. We give a brief overview of the NOMAC
(Noise Modulation and Correlation) and Rake receivers, which were early
implementations of spread-spectrum multi-path wireless communication systems.
We examine in detail the original proof of the third-named author
characterizing identifiability of channels in terms of the maximum time and
Doppler spread of the channel, and do the same for the subsequent
generalization of that work by Bello.
The mathematical limitations inherent in the proofs of Bello and the third
author are removed by using mathematical tools unavailable at the time. We
survey more recent advances in sampling of operators and discuss the
implications of the use of periodically-weighted delta-trains as identifiers
for operator classes that satisfy Bello's criterion for identifiability,
leading to new insights into the theory of finite-dimensional Gabor systems. We
present novel results on operator sampling in higher dimensions, and review
implications and generalizations of the results to stochastic operators, MIMO
systems, and operators with unknown spreading domains
Synthesis of macrocyclic receptors with intrinsic fluorescence featuring quinizarin moieties
An unprecedented class of macrocycles with intrinsic fluorescence consisting of phenolic trimers and quinizarin is developed. Though they are lacking strong hydrogen bonds as observed in calixarenes, the two examples introduced here each adopt a vase-like conformation with all four aromatic units pointing in one direction (syn orientation). This “cone” conformation has been confirmed by NMR spectroscopy, molecular modeling, and X-ray crystallography. The laminar, electron-rich fluorophore as part of the macrocycle allows additional contacts to enclosed guest molecules