A new identification method of viscoelastic behavior: Application to the generalized Maxwell model

This paper focuses on the generalized Maxwell model (GMM) identification. The formulation of the transfer function of the GMM is defined, as well as its asymptotes. To compare identification methods of the parameters of the GMM, a test transfer function and two quality indicators are defined. Then, three graphical methods are described, the enclosing curve method, the CRONE method and an original one. But the results of graphical methods are not good enough. Thus, two optimization recursive processes are described to improve the results of graphical methods. The first one is based on an unconstrained non-linear optimization algorithm and the second one is original and allows constraining identified parameters. This new process uses the asymptotes of the modulus and the phase of the transfer function of the GMM. The result of the graphical method optimized with the new process is very accurate and fast.     

传感器建模误差对其动态性能补偿效果影响的定量分析

研究了建模误差对传感器动态性能补偿效果的影响。定量分析了一阶系统、二阶系统的建模误差与工作频带拓宽倍数之间的关系，并给出了其关系图谱。由定量分析的关系式及其图谱得出结论：对于一阶系统，补偿效果只与建模误差有关，与时间常数无关，补偿效果一般均较明显；对于二阶系统，补偿效果由误差与阻尼比来决定，在较大的范围内，阻尼比越大，则获得同样补偿效果所需的建模精度就可以越低。这可为设计可靠实用的动态补偿滤波器及评价补偿效果提供依据。     

Study of recursive model for pole-zero cancellation circuit

The output of charge sensitive amplifier （CSA） is a negative exponential signal with long decay time which will result in undershoot after C-R differentiator. Pole-zero cancellation （PZC） circuit is often applied to elim- inate undershoot in many radiation detectors. However, it is difficult to use a zero created by PZC circuit to cancel a pole in CSA output signal accurately because of the influences of electronic components inherent error and environmental factors. A novel recursive model for PZC circuit is presented based on Kirchhoff＇s Current Law （KCL） in this paper. The model is established by numerical differentiation algorithm between the input and the output signal. Some simulation experiments for a negative exponential signal are carried out using Visual Basic for Application （VBA） program and a real x-ray signal is also tested. Simulated results show that the recursive model can reduce the time constant of input signal and eliminate undershoot.     

Stochastic adaptive pole-zero assignment with convergence analysis

The adaptive control u_n is designed for the stochastic system A(z)y_n+1 = B(z)u_n+C(z)w_n+1 with unknown constant matrix coefficients in the polynomials A(z), B(z) and C(z) in the shift-back operator with the purposes that (1) the unknown matrices are strongly consistently estimated and (2) the poles and zeros are replaced in such a way that the system itself is transferred to A⁰(z)y_n+1 = B⁰(z)u_n⁰+_n+1 with given A⁰(z), B⁰(z) and u_n⁰ so that the pole-zero assignment error {_n+1} is minimized. The problem of adaptive pole-zero assignment combined with tracking is also considered in this paper. Conditions used are imposed only on A(z), B(z) and C(z).     

Design of IIR filters using a pole-zero mapping approach

This paper presents a new technique for designing IIR filters that have minimum deviation from equiripple response. The algorithm is also able to find transfer functions with unequal numerator and denominator orders, which are suitable for both digital and analog IIR sampled-data realizations. Elliptic filters are produced as a particular case, when equal numerator and denominator orders are specified. Pole-zero mapping is used for scalar update of optimization parameters, thereby reducing the algorithm complexity. Zeros are structurally allocated on the unit circumference for efficient stopband shaping. Moreover, filter stability is easily enforced by restricting the radii of the poles to be lower than 1. A Taylor series expansion is employed to determine the step size of the parameter updates. The proposed approach is based on evaluations of partial cost functions to avoid local minima, and hence increase the robustness and the convergence rate of the optimization process. Design examples are shown to illustrate the efficacy of the proposed design technique, compared to alternative design techniques.     

零极点配置控制器及其在随机参数液压系统中的应用

根据状态反馈控制构成零极点配置控制系统，通过大量的仿真试验研究，说明这种控制方法能有效地改善随机参数影响下的液压控制系统的性能。     

Speech analysis by pole-zero decomposition of short-time spectra

A new method for representation of speech spectra based on a pole-zero decomposition technique is proposed in this paper. In this method the parameters of a pole-zero model for the smoothed short-time spectrum of speech are determined by adopting a cepstral matching criterion. The cepstral coefficients of the impulse response of the model are equal to the cepstral coefficients of the signal up to a specified number which determine the order of the model system. This is analogous to autocorrelation matching in linear prediction analysis. It is shown that the model spectrum represents both peaks and valleys of the smoothed spectrum equally well, unlike the all pole model of linear prediction analysis where only the peaks are well represented. The pole and zero parameters are derived in an identical manner by approximately deconvolving the pole and zero contributions in the cepstral domain. The residual from the inverse pole-zero system can be used to obtain information about the excitation signal.     

基于多媒体WAV文件的语音特征识别

Ｗｉｎｄｏｗｓ的ＷＡＶ文件提供的语音信息可以满足语音特征识别的要求。根据讲话者在讲话时鼻腔相对固定以及汉语鼻音声母少的特点,使用极零模型,并以所有汉语鼻声母音节的零点谱为参数,实现汉语讲话音辨别。所选择的参数有效,系统模板存储量少,系统训练和识别的运算量小。     

热处理电阻炉温度的自适应零极点配置控制

本文介绍了能同时考虑系统的伺服性能和调节性能的自适应零极点配置控制的基本原理,并成功地将其应用于热处理电阻炉的温度控制中。     

一种采用增益增强方法的CMOS全差分运算放大器

设计了一种全差分、增益增强CMOS运算放大器。该放大器由三个折叠式共源共栅运算放大器组成，可用于12位40MHz采样频率的流水线A／D转换器。详细分析了折叠式共源共栅运算放大器中由增加增益增强电路产生的零极点对。该放大器在0.35μm CMOS工艺中开环增益为112dB，单位增益带宽为494MHz。