Prolog to: Services, Architectures, and Protocols for Space Data Systems: a tutorial introduction to the paper by Helgert
Article Abstract:
The Consultative Committee for Space Data Systems (CCSDS), an international effort of national space agencies, is working on a comprehensive set of standards for space data systems. The standards cover techniques for data classification, transmission and handling. The standardization of space data systems should lower their cost by standardizing techniques, components and services, and by creating cross-support services between different space agencies. CCSDS's generic model, the CCSDS principal network (CPN), consists of an on-board subnetwork, a spacelink subnetwork and a ground subnetwork. The network's bearer services correspond to layers 1, 2 and 3 of the Open Systems Interconnection reference model. Hermann J. Herlgert's paper, 'Services, Architectures, and Protocols for Space Data Systems,' comments on the progress CCSDS has made in the area of space data systems standards so far.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1991
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Prolog to layer assignment for printed circuit boards and integrated circuits
Article Abstract:
There are many technological commonalities between integrated circuits and printed circuit board design and manufacture. Both have evolved considerably in terms of circuit density over several decades. Layer assignment is becoming a significant issue to integrated circuits. Vias reduction is important for cutting costs and enhancing reliability. Additionally, layer assignment is used to minimize path lengths and a board's surface area. Layer assignment is carried out through either constrained or unconstrained processes, and algorithms have been developed for both approaches. The most important objective of integrated circuit design is the maximization of performance. Joy and Ciesielski review the history of layer assignment, and present details on a variety of algorithms. Some of the algorithms minimize vias and optimize performance.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1992
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Estimating and interpreting the instantaneous frequency of a signal -- Part 1: fundamentals
Article Abstract:
A simple sinusoid's frequency is well-defined, but non-sinusoidal periodic signals are more complex yet also have well-defined frequencies. The majority of information-carrying signals are not simple sinusoids and tend to be nonstationary random processes with spectral characteristics that vary with time. The concept of instantaneous frequency (IF) was developed to deal with such processes. The theory behind the IF concept, its definitions and various functions are presented. The relationship between instantaneous frequency and group delay is explored. The extent to which the IF corresponds to an intuitive expectation of reality is considered. The notions of monocomponent and multicomponent signals and instantaneous bandwidth are discussed.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1992
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