Automatic adaptive multi-point moment matching for descriptor system model order reduction

We propose a novel automatic adaptive multi-point moment matching algorithm for model order reduction (MOR) of descriptor systems. The algorithm implements both adaptive frequency expansion point selection and automatic moment order control via a transfer function based error metric. Without a priori information of the system response, the proposed algorithm guarantees a much higher global accuracy compared with standard multi-point moment matching without adaptation. The moments are computed via a generalized Sylvester equation which is subsequently solved by a newly proposed generalized alternating direction implicit (GADI) method. Numerical examples then confirm the efficacy of the proposed schemes. © 2013 IEEE.published_or_final_versio

Noise-Sensitive Loops Identification for Linear Time-Varying Analog Circuits

The continuing scaling of VLSI technology and the increase of design complexity have rendered the robustness of analog circuits a significant design concern. Analog circuits with strong parasitic effects can be modeled using a multi-loop structure, which is more sophisticated than the traditional single feedback loop structure and results in a more complex small signal stability analysis from the noise perspective. A Loop Finder algorithm has been proposed to allow designers to detect and identify noise-sensitive return loops, which are also called "unstable" loops in previous works, without the need to add breakpoints in the circuit. Besides, efficient pole discovery and impedance computation methods have been explored so that the Loop Finder algorithm can deal with very large scale analog circuits in a reasonable amount of time. However, this algorithm only works for circuits that can be described using a linear time-invariant (LTI) system model. Many practical circuits, such as switch capacitor filters, mixers and so on, have time-varying behaviors. To describe such circuits, a linear time-varying (LTV) system model needs to be employed. In this research, we first examine the stability property of LTV systems in time domain, mostly based upon the Floquet Theory. We then take an in-depth look at the transfer function of an LTV system in the frequency domain and build the link between it and the Floquet theory. Finally, we propose an efficient algorithm for identifying noise-sensitive loops in linear time-varying circuits. This methodology provides a unifying solution for loop-based noise analysis for both LTI and LTV circuits

Engineering Education and Research Using MATLAB

MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks