Mineo Kaneko

Oscillation fault diagnosis for analog circuits based on boundary search with perturbation model

In this paper, a novel method for oscillation fault diagnosis for analog circuits is presented. Our method is based on the test whether there exist or not a solution of unknown parameters (transconductances of transistors) which makes nodal admittance matrix singular. The boundary search method for testing the existence of such a solution has been modified, and a pre-processing for diagnosis has been developed by which candidates for the cause of oscillation fault can be selected from various element value perturbations and stray elements in the circuit under test.<<ETX>>

AR spectrum estimation based on wavelet representation

A new adaptive AR spectrum estimation method is proposed. The cost function is defined by using the discrete-time wavelet transform coefficients of the linear prediction error. Instead of a single window throughout the whole frequency spectrum, a wavelet-like windowing method is used to increase the frequency resolution of the low-frequency components and to improve the time resolution of the high-frequency components. Special properties of the covariance matrix are used to derive an RLS algorithm which requires O(M/sup 2/) operations. Simulation results show that the wavelet based spectrum estimation method gives fine frequency resolution at low frequencies and good time resolution at high frequencies, while with conventional methods it is possible to have only one of these characteristics.<<ETX>>

AR spectral estimation based on multi-window analysis of the linear prediction error

A new method for autoregressive (AR) spectral analysis and a fast-transversal-filters (FTF) recursive algorithm are introduced. While conventional least-squares (LS) methods use a single windowing function in the analysis of the linear prediction error, the proposed method decomposes the linear prediction error into several bands and analyzes each of them through a different window. With this approach, the variance of spectral estimates and the tracking ability of the spectral analyzer can be traded off throughout the frequency spectrum, giving rise to spectral estimates that represent the true underlying spectrum with better fidelity than conventional LS methods. Mathematical background for the design of fast recursive algorithms for multi-window LS is exposed and an FTF algorithm is derived. Simulations comparing the performance of conventional and multi-window LS are shown.

Multi-band decomposition of the linear prediction error applied to the least-mean-square method with fixed and variable step-sizes

New least-mean-square adaptive algorithms based on multi-band decomposition of the linear prediction error are presented. In the first part of this paper the mathematical background for a stochastic approach to the multi-band decomposition-base scheme, where time and frequency resolutions are traded off along the frequency domain by using different step-sizes in the analysis of distinct frequencies, is presented and a least-mean-square algorithm with fixed step-sizes is derived. In the second part, an algorithm with independent variable step-sizes to allow time and frequency resolutions to be traded off in both time and frequency domains is introduced. Computer experiments compare the performance of multi-band and conventional least-mean-square methods when applied to autoregressive spectral estimation.

RLS algorithms for adaptive AR spectrum analysis based on multi-band decomposition of the linear prediction error

A structure for adaptive AR spectral estimation based on multi-band decomposition of the linear prediction error is analyzed and two RLS algorithms to solve the related adaptive filtering problem are derived. The presented structure gives rise to spectral estimates that represent the true underlying spectrum with better fidelity than conventional LS methods by allowing an arbitrary trade-off between variance of spectral estimates and tracking ability of the estimator along the frequency domain. The linear prediction error is decomposed through a power complementary filter bank and components of each band are analyzed by different window lengths, allowing long windows to track slowly varying signals and short windows to observe fastly varying components. The correlation matrix of the input signal is shown to satisfy both time-update and order-update properties for rectangular windowing functions, and an RLS algorithm based on each property is presented. Also, simulations comparing the performance of conventional and the proposed multi-band LS methods are depicted and discussed.

A distributed reconfiguration controller for linear array harvest problem: hierarchically quasi-normalized neural approach

WSI is considered liable to have several faults at the beginning of the production stage and during its operating lifetime. This paper describes a design of distributed controller for reconfiguration on harvesting linear array system as a degradable system with assumption that not only basic cells but also the connection links are subject to fault condition. An inherently distributed feature of a new class of cellular neural network is used in hierarchical method. The proposed method is a simple heuristic distributed process with cellular (next neighbor) information. It has simple structures that have minimum penalty in WSI area thus minimizing the reliability cost.<<ETX>>

Fault diagnosis with short circuit for linear analog networks

A novel method to prepare the fault dictionary for the short circuit faults in linear analog networks is proposed. In this method, the whole dictionary can be made with computational complexity O(n/sup 3/), where n denotes the number of nodes in the network. The authors discuss the volume of the dictionary, and an alternative fault diagnosis algorithm is presented, in which memories for the dictionary can be reduced to 2/m/sup 2/ times compared with the conventional algorithm, where m is the number of accessible nodes.<<ETX>>

Logical function and delay time extraction from MOS circuit data

An algorithm to extract logical function and delay-time from CMOS circuit-level data is proposed. The resultant data from this algorithm is a logic-level circuit description. It is applied to conventional logic simulators. As a result, a large circuit can be simulated at once, and the time needed for simulation and verification is saved. The algorithm consists of three parts, network partitioning, extraction of logical function, and extraction of delay time.<<ETX>>

Frequency dependent boundedness property for switched capacitor networks

A state equation model for switched-capacitor circuits is proposed. The model is similar in style to that using conventional differential state equations in the continuous-time domain, but differential operations are replaced with forward and backward Euler approximations. A frequency-dependent boundedness property and a partially-relaxed boundedness property are formulated in terms of an MED (mixed Euler difference) equation model, and a circuit-design problem based on these properties and its one feasible solution are derived.<<ETX>>