Semistate design theory

Using semistate theory forward and reverse binary hysteresis operators are defined from which design equations result for relevant circuits. Through variation of the design parameters swept hysteresis is introduced and experimental results presented on it.     

Semistate theory and analog VLSI design

Semistate theory as applied to electronic circuits is reviewed in a tutorial fashion. The resulting theory is applied to the design of linear VLSI circuits using an admittance framework for which the main components are MOS capacitors, differential pairs and current mirrors. The results are extended to nonlinear designs through the use of CMOS multipliers.     

A Novel Log-Domain Differentiator

A log-domain differentiator circuit, constructed using an appropriate input stage and a multiplier block, is proposed in this Letter. The input stage compresses the voltage at the capacitor's nodes and simultaneously produces a replica of the current that flows through the capacitor. The multiplier block realizes the desired output current. The analysis of the proposed circuit has been verified through simulation results.     

A Differentiator for Low-Frequency Signals

An electronic differentiator specifically for low-frequency signals is described. The difference between a signal and its staircase approximation is computed; the peaks of this function approximate the time derivative of the input signal. By regulating the width of the steps in the staircase function, very slow signals can be differentiated.     

A Square-Root Domain Differentiator Circuit

Companding circuits are very useful blocks for realizing low-voltage, high-frequency analog systems. They are implemented using the translinear principle and the quadratic/exponential I-V characteristic of MOS/BJT transistor. In this paper, a Square-Root Domain differentiator is proposed. It is constructed from an appropriate input stage that converts the input current into a compressed voltage at a capacitor's node, and simultaneously senses the capacitor's current. The overall configuration of the differentiator also includes a current geometric-mean circuit and a multiplier, both based on a translinear loop. An attractive characteristic of the proposed circuits is their immunity to body effect. HSPICE simulation results were used for evaluating the behaviour of the differentiator.     

有源微分电路设计

用理想运放模型设计的有源微分电路的不足表现为，幅频特性有远离微分规律的尖峰，符合微分规律的频带不宽。为此提出在有源微分电路的传递函数中计及实际运放幅频特性，增加与输入电容串联的电阻，可使有源微分电路的幅频特性没有不符合微分规律的尖峰，符合微分规律的频带达到最宽。     

Low-Voltage Differentiator for VHF Filtering

In this paper a G _m -C resonator circuit is proposed which is based on a new current-mode differentiating concept, compatible with low voltage and very high frequency operation.A prototype 4th-order 200 MHz band pass filter has been fabricated using a 0.8 m CMOS process and shows a side-band rejection lower than –80 dB. This response confirms the feasibility of the proposed resonator in very-high frequency applications such as IF band pass sections of RF front-end circuits. The filter consumes less than 5.5 mW from a 2.7 V supply and the measured dynamic range is 57 dB at IM3 of 0.5%, where the active area is 0.12 mm².     

用闪存区别手机价值

要确定一部现代电影的时代背景,一个简单的方法是看演员使用的手机,要判断一部手机的价值,同样可以通过看手机的存储容量.内存成为手机设计的一个关键,通过设备上的闪存,运营商才能够提供音乐、图片和视频服务.     

Design of Wideband Fractional-Order Differentiator Using Interlaced Sampling Method

In this paper, the design of a wideband digital fractional-order differentiator (FOD) is investigated. First, conventional FOD designs are reviewed, and the reconstruction formula of the interlaced sampling method is used to design the proposed wideband FOD by index substitution and the Grünwald–Letnikov fractional derivative. Because a closed-form window design is obtained, the filter coefficients are easily computed. Then, the weighted least squares and convex optimization methods are applied to design non-sparse digital FODs that are optimal in the least squares or min–max sense. Next, the iterative hard thresholding and orthogonal matching pursuit methods are used to design sparse digital FODs to reduce the implementation complexity. Finally, several numerical examples are presented to show that the proposed FODs have smaller design errors in the high-frequency band than conventional digital FODs that do not use the auxiliary interlaced sampling signal.     

A ?P-Controlled Sliding Integrating-Type Differentiator for Biomedical Signal Processing: Application to dc Ocular Rheography

This paper describes a measurement technique for precise evaluation of hematic ocular flow. The main characteristics and advantages of the proposed technique over conventional approaches are first pointed out. Next, the design criteria and the performance achievable with the prototype instrument developed to carry out the measurement completely automatically, are examined in detail. The instrument, thanks to its microprocessor-based implementation, allows a certain degree of tailoring of the measurement in accordance with the patient's peculiarities. Moreover, it provides the possibility of monitoring the ocular arterial inflow during the test, thus guaranteeing that safety limits will not be exceeded.     

基于改进离散跟踪微分器的目标状态估计算法

目前,大多数目标跟踪算法都是基于模型的,不正确的模型经常导致错误的结果。为此,提出了一种不依赖于模型的目标状态估计算法。首先,针对信号跟踪的特点,在控制不受限制的条件下,推导出了二阶离散系统最速控制综合函数;然后,基于此控制函数构造了一种简单的快速离散跟踪微分器;最后,将此离散跟踪微分器与移动平均技术结合用于目标的状态估计。数值仿真结果表明提出的方法对输入信号具有非常好的跟踪能力,能很好地滤除噪声且能给出较好的微分信号。     

基于跟踪微分器的滚仰式成像导引头视线角速率估计

针对滚仰式半捷联成像导引头难以直接获得精确的视线角速率这一问题,提出利用弹体姿态角速率、失调角、框架滚仰角等信息解算出惯性系下的视线角的方法.针对解算出的惯性系下的视线角,通过选择合适的跟踪微分器提取出惯性系下的视线角速率信息.仿真试验表明,选择合适的跟踪微分器能够在大背景噪声下对惯性系下解算出的视线角连续平滑地微分,进而可得到精确的视线角速率.     

Fractional Order Digital Differentiator Design Based on Power Function and Least squares

In this article, we propose the use of power function and least squares method for designing of a fractional order digital differentiator. The input signal is transformed into a power function by using Taylor series expansion, and its fractional derivative is computed using the Grunwald–Letnikov (G–L) definition. Next, the fractional order digital differentiator is modelled as a finite impulse response (FIR) system that yields fractional order derivative of the G–L type for a power function. The FIR system coefficients are obtained by using the least squares method. Two examples are used to demonstrate that the fractional derivative of the digital signals is computed by using the proposed technique. The results of the third and fourth examples reveal that the proposed technique gives superior performance in comparison with the existing techniques.     

无人动力伞带跟踪微分器的高度控制方法

为全面改善无人动力伞飞行高度控制性能,提出一种带跟踪微分器的积分先行控制(TD-IPD)方法。以线性二次型最优控制引出的积分先行控制器为基础,考虑到微分环节的干扰问题,引入跟踪微分器将信号从干扰中分离出来,并用最速控制综合函数fsun(·)减小达到稳态时所用步数;由于积分环节易饱和,采用饱和补偿方法对积分环节结构进行修改,从而提高积分环节抗饱和能力;以某动力伞的高度控制为对象,通过Matlab仿真验证了所提方法的有效性。     

An Effective Approach to Finding Differentiator Window Functions Based on Sinc Sum Function

An approach to finding digital differentiator window functions is studied. The frequency response of the truncated ideal differentiator is expressed by two parts. One is the ideal frequency response and the other is the deviation on the interval from ω=0 to ω=π. The deviation expression is the sum of weighted functions, where the general expression of these functions is equal to the half-sum of a pair of sinc sum functions plus π, and each weight is a window constant. Using the properties of the sinc sum function eight properties of the general expression and six properties of the deviation expression are deduced. By these properties both the relative errors of the passband and the change of their ripples can be small if each weight is proper and the truncated ideal differentiator is ideal at ω=0. From the expression of the deviation a matrix equation with window constants as unknowns can be written. Examples are given about how to write the matrix equations and how to find the optimized window constants. Four new differentiator windows as a family are obtained. These windows belong to the fixed window. Different from existing windows, the new windows are optimized in terms of reducing the relative errors of the passband. Comparisons show that new windows are better or much better than the Hanning, Hamming, Blackman, Kaiser, Chebyshev and polynomial windows in terms of differentiator performances.     

卓尔InfoGate UTM在政府行业中的应用

政府网络所面临的安全威胁为了在新一轮的国际竞争中占据有利地位,各国都将电子政务的建设作为一项重要的工作,我国政务信息化的发展近年来也取得了很大的成绩,对国家信息产业的发展也起着重要的推动作用。但是,我国政府网络也面临着越来     

Frequency and Offset Online Estimation of Sinusoidal Signals Based on High-Order Nonlinear Continuous Differentiator

Real-time parameter identification of si-nusoidal signals is an essential research topic due to its broad utilization in both theoretical studies and engineer-ing practice. A tracking differentiator based online estima-tion framework has been proposed to simultaneously iden-tify frequencies and offset of given multi-sinusoidal signal. Tracking differentiator is exploited in presented framework to track the time derivatives of measurements which are then utilized to estimate the frequencies and offset. We introduce a tracking differentiator called high-order non-linear continuous differentiator into the framework, giving birth to a new estimation algorithm. Comparative exper-iments on both single and two sinusoidal signal are sim-ulated, indicating the superiority of proposed method on both convergent speed and estimation accuracy.     

Realization of a Constant Phase Element and Its Performance Study in a Differentiator Circuit

A simple method for fabricating a constant phase element (CPE) has been discussed. Dependence of the phase angle on several physical parameters have also been elaborated. Finally, a fractional-order differentiator circuit has been constructed using the CPE, and its performance has been compared with the simulated results.     

以住宅为例谈建筑设计在科技信息下的可变形态及其实现

唯有运动才是一切事物的动力源泉,寻求动态的美是人们与生下来的本能,所以,对于建筑来讲,其形态的变化也应同这种动态的特点相符合。本文以住宅建筑为例,论述了在当前科技信息基础上,建筑可变形态设计的价值、重要性及其方法,目的在于进一步提高设计美感,确保人们居住舒适、安全。