| With the tremendous development in electronic computer technique, computer aided systems are playing growing important roles in many fields. In years, many analog electronics experts all over the world think that the computer aided symbolic analysis has its important practicable value in analog circuits' analysis and design. It's long worldwide known that it's extremely difficult to process symbolic analysis in nonlinear circuits and systems. Globally, there are very few symbolic simulators for nonlinear circuits at present, and their functions are usually weak. Symbolic Analysis Program for Nonlinear Circuits (SAPNC), established by Dr. Chen Wen et al. under the direction of Prof. Qiu Shuisheng, pays great attention in symbolic simulation of strong-nonlinear circuits. Still in its infancy, SAPNC is the most powerful nonlinear symbolic simulator in bo(?) domestics and international.This thesis is worked with the foundation of infant SAPNC. The research work includes:Some improvement and expansion of SAPNC. Accomplish a satisfactory and practicable valuable formula approximation algorithm, and program it to corresponding sub-module linked to SAPNC. Extend the nonlinear analysis function of SAPNC, propose an expanded algorithm of Equivalent Small Parameter Method to solve multi-variable weak-nonlinear circuits and systems, and program it to corresponding sub-module. Some primary works in comparison of Equivalent Small Parameter Method and Volterra Series Method, in respect of computer aided symbolic analysis.The Results confirm that, SAPNC is a circuits' symbolic simulator with kinds of basic functions, and with further improvement it could be a useful tool for both teaching and research; Equivalent Small Parameter Method is a simple and practical analytic approximation algorithm for solving nonlinear circuits and systems with high accuracy, and it has certain advantages in calculation accuracy, needed memory and calculation speed, compared with Volterra Series Method. |
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