Modified Realization Technique for Digital Filters Derived from Analog Counterparts

A simple realization scheme for one-dimensional and two-dimensional recursive digital filters derived from analog reference transfer functions is presented. The method is based on proper predistortion of the analog transfer function to obtain a new Hurwitz polynomial. Analog-to-digital transformations, such as the bilinear transformation, are then applied to the resulting predistorted reference transfer function to obtain the discrete version of the system. It is shown that a proper choice of the predistorting function will yield digital realizations which are free of the delay-free loops and in most cases are near minimal. To illustrate the simplicity and efficiency of the technique, examples of 1-D and 2-D cases are worked out. The proposed scheme can readily be extended to include the multi-dimensional case.     

Expected power bound and stability of two-dimensional digital filters with multiplicative noise in the FMLSS model

This paper studies the two-dimensional (2-D) expected power bound (EPB) for 2-D digital filters with multiplicative noise in the Fornasini-Marchesini local state-space (FMLSS) model. By virtue of a class of linear matrix inequalities (LMIs), the novel existence criterion of 2-D EPB for 2-D digital filters in the considered model is obtained. The corresponding stabilization controller design method is presented based on the above criterion. Finally, two examples are presented to verify the effectiveness of our results.     

Design of 2-D stable analog and recursive digital filters using properties of the derivative of even or odd Parts of Hurwitz polynomials

In this paper, a method for the design of 2-D analog and recursive digital filters is presented. Starting from a structure in the analog domain, suitable even or odd parts of two-variable Hurwitz polynomials are generated. This enables 2-variable very strictly Hurwitz polynomials (VSHP) to be obtained,² thus avoiding non-essential singularities of the second kind. Thus it will ensure a stable 2-D recursive digital filter obtained by the use of bilinear transformations. Examples are given to illustrate the method.     

A new realization of 2-D adaptive separable-denominator state-space filters based on DLMS algorithm suitable for parallel processing

In the application of 2-D adaptive filters, a large amount of data must be processed and real-time processing is often required. In this paper, a new parallel-form realization of 2-D adaptive separable-denominator state-space filters suitable for high-speed processing is proposed. First, the 2-D local state-space model suitable for parallel processing is introduced. Next, the adaptive algorithm for this model is developed. This algorithm is based on the delayed least mean square (DLMS) method. In addition, the computation time required for the update of the coefficients is investigated. Finally, the proposed technique is applied to the design of 2-D digital filters in the spatial domain.     

Realization of digital transfer functions using cascaded lattice and ladder block structures

Several techniques are available for implementing a scalar digital filter using lattice and ladder structures which are known to yield low noise realizations. Of these, the lattice and ladder structures proposed by Gray and Markel have the advantage of being internally scaled. Block implementation of a scalar digital filter offers a number of advantages. In this paper, new algorithms to realize block digital filters in the form of cascaded lattice or ladder two-pairs are proposed. Block lattice and ladder structures similar to Gray and Markel's scalar structure are obtained by using Levinson recursion. Also, normalized block lattice and ladder structures are developed.     

A new type of wave digital filter

This paper proposes a new wave digital filter derived from doubly terminated LC-ladder networks by replacing each series or shunt arm element of the ladder by its equivalent digital two-port. It is shown that such two-ports may be cascaded without the use of adapters defined by Fettweis (1). A number of realizations of the wave digital two-ports, which are canonic with respect to both multipliers and delays, have been obtained. Also a realization which is canonic with respect to multipliers only is given and an example considered using this realization. The sensitivity of this filter with respect to the multiplier coefficient changes due to finite word length is compared with the conventional cascaded digital filter and also the one proposed by Renner and Gupta. It is found that the proposed filter appears to be a more desirable form of implementation than the conventional cascade form and comparable to that of Renner and Gupta (2).     

IIR数字陷波器的设计及FPGA实现

IIR（无限冲激响应）数字滤波器在许多领域得到广泛应用.这里介绍了一种利用Matlab设计一个IIR数字陷波器的方法,接着在硬件实现时将其转化为二阶级联形式,以VerilogHDL语言书写模块,最后利用Altera公司的Quartus Ⅱ软件进行FPGA设计及仿真.     

Transfer function realization of a class of doubly-terminated two-variable lossless networks and their application in linear-phase 2-dimensional digital filter design

A method is presented for the design of a class of two-dimensional (2-D) stable digital filters satisfying prescribed magnitude and constant group delay specifications. The design method generates a 2-D digital transfer function which is a product of two transfer functions H₁(z₁,z₂) and H₂(z₁,z₂), corresponding to a recursive filter and a nonrecursive filter, respectively, Component H₁(z₁,z₂) ensures a wave-digital realization, that is, the design method guarantees the generation of a corresponding analog function H_1A(s₁,s₂) which is realizable as the transfer function of a doubly-terminated two-variable lossless network. Thus the design technique ensures that not only is a given frequency response achieved, but also the generated transfer function is realizable as a cascade of a wave-digital filter and a nonrecursive digital filter. The class of filters considered here is one in which the doubly-terminated analog network used to realize the wave digital filter is a cascade of s₁- and s₂-variable lossess two-ports with all their transmission zeros at infinity.     

On the Generalization of Block Pulse Operational Matrices for Fractional and Operational Calculus

A more rigorous derivation for the generalized block pulse operational matrices is proposed in this paper. The Riemann-Liouville fractional integral for repeated fractional (and operational) integration is integrated exactly, then expanded in block pulse functions to yield the generalized block pulse operational matrices. The generalized block pulse operational matrices perform as s^-α(α\s>;0,α∈R) in the Laplace domain and as fractional (and operational) integrators in the time domain. Also, the generalized block pulse operational matrices of differentiation which correspond to s^α(α\s>;0,α∈R) in the Laplace domain are derived. Based on these results, the inversions of rational and irrational transfer functions are proposed in a simple, accurate and efficient way.     

A simple form synthesis of linear time-variant digital filter via spectral decomposition of its impulse response

The paper describes a new technique to synthesize a finite impulse response of linear time-variant (LTV) digital filter. First, a finite impulse response is decomposed into a sum of products of two orthogonal sequences. The direct implementation of the decomposed impulse response leads to the parallel connection of linear time-invariant (LTI) digital filters, followed by time-varying multipliers. A simple filter structure is obtained by properly modifying the sequences to realize the parallel form structure as a cascade connection of first- or second-order recursive LTI filters. The structure is easy to implement on a computer and saves computation time. Numerical examples illustrating the technique are included.     

Modelling of linear discrete-time systems using modified cauer continued fraction

An algorithm, amenable for programming on a digital computer, has been presented for the modelling of linear discrete-time systems, as an alternative to the procedure of Shamash (1). The transformations inherent in the procedure are easily accomplished by the synthetic division technique. With the use of modified Cauer form of continued fraction (MCF), the new method matches a set of both the time-moments and Markov parameters of the system and of the model, as in the procedure of Parthasarathy and Singh (2), giving a better approximation to the system response at all times. A distinct feature of the proposed algorithm compared with the earlier methods of discrete system reduction (1),(2), is that a number of reduced-order models are generated simultaneously; this allows scope for better selection in choosing the right model for system analysis and design.     

Direct design of recursive digital filters based on a new stability test

In this paper we present an alternative approach to the direct design of 1-D recursive digital filters satisfying prescribed magnitude specifications with or without constant group delay characteristic. This method uses an iterative method to calculate the coefficients of the filter's transfer function and guarantees the stability of the designed filter using a new stability test reported by Ramachandran and Gargour. To illustrate the usefulness of the technique, examples are given.     

基于FPGA多带宽合成孔径雷达系统的数字接收技术

针对传统多带宽合成孔径雷达系统需要多个滤波器和多种采样时钟等问题,提出一种新的数字处理方法,并详细介绍了算法方案、仿真结果和基于现场可编程门阵列(FPGA)的算法实现.该方法仅需一个最高频率的采样时钟获取离散化数据,通过对数据的插值得到其他较低时钟频率的数据,而对不同带宽信号的滤波由数字滤波器来实现.这种方法简化了系统设计,提高了系统可靠性.     

数字化转型下产品与服务创新优先级演化分析———基于海尔智家案例

创新是企业赢得竞争优势的关键，厘清解决好产品创新与服务创新的优先级问题有助于制造企业服务化战略实施的顺利展开，而随着制造企业数字化应用场景的增多程度不断加深，使得两类创新优先级决策愈加困难。借助种群互惠模型解析了构建出两类创新共生演化规律演化模型，分析两类创新共生模式；结合海尔智家2011-2019年实施数字化与服务化转型的纵向案例分析，划分了其数字化转型的阶段，据此揭示解析了不同阶段下两类创新关系特征及动态演化规律。研究表明：数字化转型下两类创新存在着非对称互惠共生关系，且优先级变动具有阶段性特征；随着企业主导逻辑的转变，数字化转型经历着由内及外，再到融合，有效加速了两类创新协同发展。研究结果有助于增强对数字化环境下制造企业对两类创新相互关系的理解，为制造企业实施数字化与服务化转型提供理论指导。     

Realizability-Preserving Transformations for Digital and Analog Filters

The theoretical basis for the design of analog and digital filters by prototype and transformation is studied. Necessary and sufficient conditions are developed for a transformation to preserve realizibility as well as the frequency response. The attendant structural properties of such transformations are developed and compared with the reactance transformations of classical analog filter theory. The superiority of direct analog-to-digital transformation to the Constantinides approach is proven.     

创新驱动社会服务数字转型发展的趋势、国内外实践与建议

党的十九大报告明确指出“我国社会主要矛盾已经转化为人民日益增长的美好生活需要和不平衡不充分的发展之间的矛盾”。为破解这一矛盾,迫切需要把握创新驱动社会服务数字转型发展战略机遇,推动社会服务高质量发展。文章研判了政务服务、教育服务、医疗卫生服务、养老服务、就业服务、公共安全服务等社会服务领域创新驱动数字转型发展趋势,梳理了发达经济体创新驱动社会服务数字转型的政策实践,总结了中国创新驱动社会服务数字转型发展的成效,明确中国创新驱动社会服务数字转型的发展思路,并提出4个方面政策建议：（1）构建社会服务数字转型发展技术创新体系;（2）推进创新驱动数字赋能政府服务流程再造;（3）推动创新驱动数字赋能公共服务转型发展;（4）营造数字赋能社会服务转型政策法律环境。     

Plastid transformation: Advances and challenges for its implementation in agricultural crops

Chloroplast biotechnology has emerged as a promissory platform for the development of modified plants to express products aimed mainly at the pharmaceutical, agricultural, and energy industries. This technology’s high value is due to its high capacity for the mass production of proteins. Moreover, the interest in chloroplasts has increased because of the possibility of expressing multiple genes in a single transformation event without the risk of epigenetic effects. Although this technology solves several problems caused by nuclear genetic engineering, such as turning plants into safe bio-factories, some issues must still be addressed in relation to the optimization of regulatory regions for efficient gene expression, cereal transformation, gene expression in non-green tissues, and low transformation efficiency. In this article, we provide information on the transformation of plastids and discuss the most recent achievements in chloroplast bioengineering and its impact on the biopharmaceutical and agricultural industries; we also discuss new tools that can be used to solve current challenges for their successful establishment in recalcitrant crops such as monocots.How to cite: Quintín Rascón-Cruz Q, González-Barriga CD, Iglesias-Figueroa BF, et al. Plastid transformation: Advances and challenges for its implementation in agricultural crops. Electron J Biotechnol 2021;51. https://doi.org/10.1016/j.ejbt.2021.03.005     

Mapping the mix: Linking instruments,settings and target groups in the study of policy mixes

This article proposes the extension of a conceptual framework aimed at analysing policy mixes and their outcomes and demonstrates its value added for the study of sustainability transitions. The argument is that policy mixes research should not focus only on the form of policy instruments, but also on their implementation context. Policy mix form designates the specific policy instruments that are involved according to a policy strategy. Policy mix context includes the specific setting where each policy measure is implemented, such as enterprise or family. It also includes the specific target group of each measure, such as youth or smokers. We apply this conceptual framework to the policy concept and implementation of tobacco control policies in Switzerland, which are an exemplary case for analysing transitions as they are geared towards behavioural change. In a mixed method approach, we triangulate different sets of quantitative and qualitative indicators in order to assess the implementation of eleven subnational policy mixes. Our findings show that taking into account the moderating role of settings between policy instruments and target groups allows for a more in depth analysis of policy processes. Observing the interactions between the four elements policy instruments, policy strategy, the implementation settings and the target groups allows capturing the complexity of policy mixes, at the crossroads of policy design, policy implementation and policy outcomes. Taking implementation settings and target groups into account in the analysis of policy mixes allows for a refined understanding of policy compliance and thus, from a broader perspective, of sustainability transitions.     

Topological interpretation of the inverse connection matrix A.sb

This paper discusses a new algebraic model of electrical networks by which a deeper understanding is achieved of the interrelation existing between a system of independent cut sets and the corresponding system of independent “contours”, in the sense of orthogonal network theory (1).The new model allows, by a redefinition of f-cut sets, to give an interpretation in terms of linear graph theory to the inverse connection matrix A^.s_b, i.e. to the transformation matrix between voltages in the orthogonal and the primitive reference frames, for a general choice of independent contours.Furthermore, a directly algebraic derivation of the voltage transformation is presented, recalling the properties of dual vector spaces and without invoking the principle of invariance of the instantaneous power.     

Model transformation based sliding mode control of discrete-time two-dimensional Fornasini–Marchesini systems

This paper investigates the problem of sliding mode control (SMC) for discrete-time two-dimensional (2-D) systems subject to external disturbances. Given a 2-D Fornasini–Marchesini (FM) local state space model, attention is focused on designing the 2-D sliding surface and sliding mode controller, which guarantees the resultant closed-loop system to be asymptotically stable. Particularly, this problem is solved using the model transformation based method. First of all, sufficient conditions are formulated for the existence of a linear sliding surface guaranteeing the asymptotic stability of the equivalent sliding mode dynamics. Based on this, a sliding mode controller is synthesized to ensure that the associated 2-D FM system satisfies the reaching condition. The efficiency of the proposed 2-D SMC law design is shown by a numerical example. This paper extends the idea of model transformation to the 2-D systems and solves the SMC problem of a more general 2-D model in FM type for the first time.