Article Abstract:
Advances in VLSI technologies have led to the implementation of very large and complex systems on a single chip. Current Computer Aided Design (CAD) tools are being pushed to their limits in order to keep up with increasing chip complexity. One of the main problems facing current CAD tools is the large amount of memory required when dealing with large systems. Most tools represent the circuit as a collection of primitives and shared information is duplicated. This paper discusses an approach for hierarchical switch-level simulation of digital circuits. The approach exploits the hierarchy to reduce the memory requirements of the simulation, allowing the simulation of circuits that are too large to simulate at the flat level. In addition, parts of the circuit can be replaced with automatically generated software models, thus increasing the simulation speed without sacrificing accuracy. The approach has been implemented in a hierarchical switch-level simulator, CHAMP. The program allows for user-supplied behavioral models, assignable delays, and bidirectional signal flow inside circuit blocks that are represented as transistor networks as well as across the boundaries of higher level blocks. (Reprinted by permission of the publisher.)
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Article Abstract:
This paper reports the simulation of a practical system which is being investigated as part of a research program in pattern recognition. It is used to show that the system is feasible and to establish the conditions in which the system is stable. SIMAN is used for the simulation enabling the user to integrate the discrete and continuous parts of the model in one package. The problem being investigated is the tracking of contours of a 2 dimensional object using a beam of light. Z-transforms have been used to model the opto-electronic contouring system. The shape is simulated either by waveform generation or by manual input of numeric data for nonuniform shapes. The paper describes the derivation of the model and the programming behind the simulation together with successful results. (Reprinted by permission of the publisher.)
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Article Abstract:
This note discusses 8086-8087 machine-language programming for simulation of nuclear reactor instrument current inputs by means of a digital-analog converter (DAC) feeding a bank of series input resistors. It also shows FORTRAN programming for generating the parameter tables used in the simulation. These techniques would be generally useful for high-speed simulation of quantities varying over many orders of magnitude. (Reprinted with permission of publisher.)
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