In 1, p. 58, the caption of Figure 1 should be “Genie Project: Paul Morton, Melvin Pirtle, and Wayne Lichtenberger. Photograph courtesy of Dennis Galloway.”
The University of California’s Project Genie was an ARPA sponsored project to create an interactive programming environment. The SDS-930 was a relatively inexpensive machine with a maximum of 32 K of ...physical memory. To create a time-sharing machine from the base SDS-930 architecture, Pirtle and Lichtenberger extended the ’930 architecture to include protection and memory mapping. Deutsch and Lampson implemented an operating system for the modified ’930. Ultimately, SDS decided to market the Berkeley modifications to the ’930 and denoted it the ’940. They sold the machine to a new company called Tymshare. Tymshare heavily modified the Berkeley operating system over more than five years. Utilizing the system call manuals and the source code from Tymshare, it is possible to trace the operating system modifications that parallel the development of disk and telecommunication hardware in the late 1960s and early 1970s. It also illustrates what is required to turn a prototype system into a hardened commercial success.
50 years of RF and microwave sampling Kahrs, M.
IEEE transactions on microwave theory and techniques,
06/2003, Letnik:
51, Številka:
6
Journal Article
Recenzirano
Measurement of microwave and UHF signals is often done with sampling techniques. In this paper, the techniques and technology of sampling of electrical signals is reviewed from 1950 to the present. ...It includes both references to the open literature, as well as an extensive review of relevant patents. It also provides an overview of sampling applications and the use of computer technology to compensate and correct for errors in the sampling process.
In 1998 the main applications of audio DSP are high quality audio coding and the digital generation and manipulation of music signals. They share common research topics including perceptual ...measurement techniques and analysis/synthesis methods. Additional important topics are hearing aids using signal processing technology and hardware architectures for digital signal processing of audio. In all these areas the 1990s have seen a significant amount of application-oriented research.
The hardware and software interface to a programmable real-time RF propagation simulator is described. First, fading models are reviewed; and next, the digital filter design of the fade spectra ...filtering is detailed along with the implementation on a floating point digital signal processor (DSP). The hardware system design is given, followed by the application of this system to radio link propagation.
Measurement of microwave and UHF signals is often done with sampling techniques. In this review, the techniques and technology of sampling of electrical signals is reviewed from the beginning of the ...twentieth century to the present. It includes both references to the open literature as well as an extensive review of relevant patents. This review is specifically oriented toward applications and not theory. It was written to introduce the Special Session on "High Speed Sampling Circuits and Techniques" at IMS 2003.
We present a component-based multi-level mixed-signal design and simulation environment for microsystems spanning the domains of electronics, mechanics, and optics. The environment provides a ...solution to the problem of accurate modeling and simulation of multi-domain devices at the system level. This is achieved by partitioning the system into components that are modeled by analytic expressions. These expressions are reduced via linearization into regions of operation for each element of the component and solved with modified nodal analysis in the frequency domain, which guarantees convergence. Feedback among components is managed by a discrete event simulator sending composite signals between components. For electrical, and mechanical components, interaction is via physical connectivity while optical signals are modeled using complex scalar wavefronts, providing the accuracy necessary to model micro-optical components. Simulation speed vs. simulation accuracy can be tuned by controlling the granularity of the regions of operation of the devices, sample density of the optical wavefronts, or the time steps of the discrete event simulator. The methodology is specifically optimized for loosely coupled systems of complex components such as are found in multi-domain microsystems.
Mixed-signal multidomain systems present a challenge for computer-aided design tools. Optical and electronic simulation tools are available as separate entities. However, to date, successful ...system-level cosimulation has not been implemented, leading to expensive refabrication. We present a unique system-level simulation tool for mixed electrooptical systems. We apply our tool Chatoyant to the simulation of an optical high-speed free-space interconnect system designed for 10-GHz speeds. The 10G free-space optical interconnect module has optical, optoelectronic, and microwave components and thus is an ideal vehicle to use as a test system. We demonstrate how Chatoyant, a mixed-signal multidomain simulator, has been used to evaluate end-to-end performance of this complex system, including the exploration of design tradeoffs and mechanical tolerancing.
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