Application Research Of The Theory Of Active Network Synthesis And Auto Design Of Analog Circuits

Technology of circuit network synthesis is one of the critical technologies of auto circuits design, and the theory of active analog circuit synthesis based on NAM(Nodal Admittance Matrix) expansion has become a hot issue in the research field of Circuits and Systems. In view that design of active analog circuits requires the computer-aided tools with higher degree of automation, the method of analog circuit synthesis with high efficiency and automation proves to be one of the key technologies to solve this problem.Moreover, this dissertation does a further study of the theory of active network synthesis, proposes the method of active analog circuit design based on NAM expansion, and embarks on the research of multi-level symbolic simulator design in analog circuits. Meanwhile, by using the admittance parameters and the scattering parameters, the method of vector fitting is taken to establish the rational functions of the complicated signals and corresponding circuit model, which solves the signal integrity issues.This dissertation makes the following contributions:1. From the perspective of matrix, method of systematical circuit design is studied by the application of the theory of active network synthesis, the method of which is applied to active filter design, including synthesis of voltage mode filter, current mode filter, trans-impedance filter, Tow-Thomas Biquad filter and conversion from the voltage mode filter to the current mode filter.2. Research of modeling of active modules using pathological elements is studied,the research of which can be applied to convert the active analog circuits to circuits network including passive elements and pathological elements. Symbolic analysis method of circuit network is presented.3. The symbolic analysis and simulation of circuit network including pathological elements are realized with the computer-aided design. Meanwhile, the behavior of active devices is described using Verilog language, the description combined with the HSPICE simulation program achieves high-level behavioral modeling of the modules and the HSPICE simulation of the concrete realization in the bottom.4. Method of synthesis of simulated inductor and FDNR(Frequency DependentNegative Resistance) is studied, simulation results of which demonstrate the effectiveness of this method of circuit synthesis. Meanwhile, the concept of pathological elements with polarity is put forward combining the theory of pathological elements and nodal admittance matrix expansion, and principle of combination of Nullors is analyzed, which solved some detailed problems in circuit modeling and circuit mapping.5. The method of vector fitting is applied to the admittance parameters and scattering parameters of the complicated signal to establish the models corresponding to rational functions. These models include Poles-Residues model, State-Space model and equivalent circuit model. In this way, an accurate approximation of the original signal is achieved and issues of the signal integrity are solved.