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.

COMMUNICATION, Standards, Standard, Standardization, Telecommunications transmission technologies, Communications protocols, Network architectures, Protocol, Telecommunications, Network Architecture, Space Exploration, Scientific Research, Data Communications, OSI Standard, International, International Telegraph and Telephone Consultative Committee

---

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.

Integrated circuits, Circuit design, Integrated circuit fabrication, Printed circuit boards, Boards/Cards, Circuit Printing

---

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.

Bandwidth, Signal processing, Estimation, Theory, Bandwidth Technology, Frequency

Similar abstracts:

• Abstracts: Prolog to planetary influences on electrical engineering (tutorial introduction to paper by Ronald N. Bracewell)
• Abstracts: On-line power system security analysis. Knowledge-based systems as operational aids in power system restoration
• Abstracts: Development of an automated windshear detection system using Doppler weather radar
• Abstracts: Thin film deposition and microelectronic and optoelectronic device fabrication and characterization in monocrystalline alpha and beta silicon carbide
• Abstracts: Scientific modeling with massively parallel SIMD computers. Mapping vision algorithms to parallel architectures

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.