Symbolic Analysis Program Research Articles

Implementation of Symbolic Analysis of Mechatronic Systems

The paper presents the theoretical background and implementation details of a multi-domain symbolic analysis program developed with the emphasis on linearized hybrid systems combining classical electrical circuits, controllers, electro-mechanical converters and mechanical parts of electric drives. The systems analyzed can be composed of both basic elements and more complex behavioral blocks (regulators, converters, drives, etc.). All models are defined in an easily extensible library. Implemented algorithms for equation/matrix-based symbolic simplification allow obtaining symbolic expressions of acceptable complexity even for larger systems.

Finding ambiguity groups in low testability analog circuits

This paper discusses a numerically efficient approach to identify complex ambiguity groups for the purpose of analog fault diagnosis in low-testability circuits. The approach presented uses a numerically efficient QR factorization technique applied to the testability matrix. Various ambiguity groups are identified. This helps to find unique solution of fault diagnosis equations or identifies which groups of components can be uniquely determined. This work extends results reported earlier in literature, where QR factorization was used in low-testability circuits, significantly increasing efficiency to determine ambiguity groups. A Matlab program that implements this method was integrated with a symbolic analysis program that generates test equations. The method is illustrated on two low-testability electronic circuits. Finally, method efficiency is tested on larger electronic circuits with several hundred tested parameters.

SSCNAP: a program for symbolic analysis of switched capacitor circuits

The authors present a symbolic switched capacitor (SC) circuit analysis program, called SSCNAP, which was developed on a microcomputer. The program is based on a method that uses numerical algorithms at all stages. Partially or totally symbolic transfer functions, large-change sensitivities, relative sensitivities, and poles and their sensitivities for arbitrary K-phase SC circuits can be obtained using SSCNAP. No topological or duty-cycle constraints have been imposed on the circuits. The discussion is limited to ideal SC circuits that do not contain any resistances.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On a family of new two‐op‐amp switched‐capacitor biquads for high‐frequency applications

AbstractThis paper presents three novel biquads derived by applying the concept of so‐called basic elements for switched‐capacitor (SC) circuits. These biquads are without continuous feedback and comprise two op‐amps. They were derived assuming a transfer function denominator of the same form as the Fleischer‐Laker type E circuit. It is shown that by a simple modification of the switching arrangement, i.e. by changing the type of the basic SC element, the effect of the amplifier finite gain on the performance of SC filters can be significantly reduced. the efficiency of this approach has been established by extensive simulation studies using the dedicated symbolic analysis program SCYMBAL. Design equations and comparison with already known biquads of this type are presented. Examples are provided to demonstrate that the proposed circuits require a low total capacitance while finite‐gain effects are considerably reduced.

Switched-capacitor biquad with low influence of finite gains

The letter describes a switched-capacitor (SC) biquad which exhibits less effect of the finite gains on the Q-factor and centre frequency than other known biquads of this type. The properties of the circuit have been established by extensive simulation studies using a symbolic analysis program.

Reduction of symbolic sparse matrices

A new general method is derived for reduction of linear systems of equations with symbolic polynomial coefficients suitable for using sparse matrix techniques. Its implementation in a program for symbolic analysis of circuits offers significant advantages over the existing reduction method.