Methods Of Complex Field Modeling And Design For Testability For Analog Circuit

With the widespread engineering applications ranging from broadband signals and non-linear systems, time-domain integral equations(TDIE) methods for analyzing transient electromagnetic scattering problems are becoming widely used nowadays. TDIE-based marching-on-in-time(MOT) scheme and its fast algorithm are researched in this dissertation, including the numerical techniques of MOT scheme, late-time stability of MOT scheme, and two-level PWTD-enhanced MOT scheme. The contents are divided into four parts shown as follows.The problem of analog fault testing and diagnosis raised a great deal of interest recently. Testability and fault modeling is the basic problem of analog fault testing and diagnosis. The traditional hard(open and short) faults and discrete parameter faults are still the mostly used fault models. These models cannot characterize all soft faults occurring in analog circuits because that the parameter of analog element are continuous. If the slope modeling method is used, the required number of test points is larger than the faults to be modeled. Base on the system transfer function, symbolic techniques can model all the parameter shifting faults. But the transfer function of circuit under test(CUT) is not always available. Hence, a fault modeling method, which can model all the possible continuous parameter shifting faults is badly needed. This method needs few test point and the transfer function is unnecessary.Based on the considerations, the mathematic foundation of complex field is given at first. Then, simulation based testing modeling method is presented. Thirdly, design for testability(DFT) methods are researched. The detailed work are as follows.1)In the complex field, the general function(relationship) between the real and imaginary parts of output voltage are derived by using thevenin’s theorem, substitution theorem and superposition theorem. This function independent from the parameter value of fault source, and it is determined by the location of fault source and circuit construction. Hence, it can model all possible continuous parameter shifting faults in an uniform way. The theoretical proof and simulation results show that with few test points, this method has high fault resolution. It is also applicable to nonlinear circuit.2)To acquire smooth fault feature curve, the complex field modeling method need lots of parameter sweep simulations. To over come this shortcoming, a much more simpler modeling method, viz., complex field circle equation based testing modeling method is presented.3)Due to that the circle equation is a quadratic equation, different circles might have two intersections besides the fault free points. It is referred to as aliasing problem. A sensitive frequency generating and compression method are proposed to solve such problem.4)Besides the frequency selection method, another DFT method, viz., structure modifying method is researched to improve the testability of CUT.