Second Order Band-Pass Filter Design Using Single CC-CDBA

Six new second order band-pass filter configurations using only a single current-controlled current differencing buffered amplifier (CC-CDBA) are proposed. Further, the proposed filters also have a minimum number of external electronic components. They realize current-mode, voltage-mode and transadmittance-mode filter characteristics. The quality factor and natural frequency can be adjusted electronically without changing the values of the passive components. The proposed filters use a minimum number of passive elements (two or three). There is no second order active filter structure which uses two passive components and one active component in the literature. The validity of the proposed filters is verified through PSpice simulations.     

Current-Mode Universal Filters Using Current Conveyors: Classification and Review

Several current-mode universal filters are reviewed. The filters are classified in two classes. The class I filters have floating passive elements, whereas class II filters have all resistors and capacitors grounded. Each class of filters includes two subclasses based on the filter’s capability to have independent control of the filter quality factor or not. The effects of nonideal second generation current conveyors are briefly discussed. Spice simulations using BSIM3 version 3.1 parameters, feature size 0.5 μm from MOSIS, are given, and a detailed comparison table is included.     

Adaptive 1-D and 2-D Filtering with Internally Passive Structures

Internally passive filters such as wave digital filters (WDF) and orthogonal filters, which have desirable properties, are developed as filter structures for adaptive filters. The equations for updating the multiplier coefficients as well as for computing the gradients are derived for these filters. The stability monitoring during the adaptation process for these filters is simple to implement. Simulation results are included to demonstrate the capability of these filters in system identification and noise cancellation. Moreover, motivated by applications of multidimensional adaptive filters in video compression and image enhancement, the proposed adaptive wave digital filters have been extended to two dimensions and applied as adaptive fan filters. Computer simulations are also conducted to show their potential applications to two-dimensional system identification and image enhancement.     

A new approach for the realization of voltage-mode second-order universal filters using current conveyors

In this work two different types of topologies are derived for realization any second-order filter characteristic by choosing properly, the admittances of passive elements. These topologies use two second-generation current conveyors (CCIIs). One of the topologies involves different types of CCIIs whereas the other uses the same type of CCIIs together with a unity gain voltage buffer. The buffer used provides not only low output impedance but also facilitates cascading of the filter circuits thus obtained. It is possible to derive many different filters realizing any second-order transfer function by the use of the proposed topologies. Moreover, the produced filters have low-sensitivity performance and permit orthogonal controlling of both the quality factor and the natural angular frequency.     

基于MOCC的电流模式连续时间滤波器

本文利用多端输出电流传送器MOCC实现电流模式低通滤波器和通用滤波器。所提出的电路结构简单 ,所有无源元件均接地 ,便于CMOS工艺实现。     

Current mode multifunction filter using two CDBAs

This paper presents a cascadable current-mode (CM) multifunction biquadratic filter. The proposed circuit realizes all five different filter transfer functions employing only two current differencing buffered amplifiers (CDBAs), while previously reported CM multifunction filters require more CDBAs and more passive component count for the same number of filter transfer function realizations. Examples for different filter transfer functions are given along with the results of circuit simulations. It is shown that theoretical and simulation results are in good agreement.     

动态运行配电网滤波装置优化配置问题的研究

针对配电网中多谐波源负荷并存的特点和多谐波源负荷工作时间的不确定性,考虑滤波装置的无功补偿性能,提出了动态运行的概念,给出了基于自适应遗传算法的动态运行配电网滤波装置递阶优化配置问题描述,通过实例分析说明了该动态运行分析方法的可行性和实用性.     

单一单位增益放大器的Q增强SC滤波器

本文阐述了采用单位增益放大器的SC滤波器的设计方法。基于无源Q增强技术,由Sallew Key有源RC电路导出了一系列Q增强的二阶SC低通、高通和带通滤波器。设计表明,本文提出的Q增强SC电路比文献给出的电路需要小得多的电容分散度。本文考察了这些电路灵敏度和有限GB对SC电路的影响。用分立元件做了实验,实验结果与理论计算相吻合。     

Voltage-mode high-Q band-pass filters and oscillators employing single CDBA and minimum number of components

In this paper, voltage-mode second order high-Q band pass filters and oscillators which employ only single current differencing buffered amplifier (CDBA) as the active component are proposed. One of the four filter circuits and two of the four oscillators described have minimum passive component count properties, without using the internal pole of the active element. These BP filters can be easily cascaded without any recourse to impedance matching circuitry. The circuits have been analysed theoretically, simulated and experimentally tested in a laboratory. It is shown that the results of simulations and experimental work are in agreement with theoretical predictions.     

一系列新的基于电流模式的二阶滤波器

本文提出了一种新的基于电流模式的二阶滤波器综合电路，适当选择电路元件，可综合出一系列电流模式二阶低通、高通和带通滤波电路，对其中部分电路进行了理论设计和灵敏度分析，结果表明本文提出的电路灵敏度低、增益可独立调节。计算机仿真结果证实了理论分析的正确性。     

Automatic Generation of Wave Digital Structures for Numerically Integrating Linear Symmetric Hyperbolic PDEs

The numerical integration of partial differential equations (PDEs) resulting from passive physical problems can be performed by simulation of the actual system with multidimensional (MD) passive wave digital filters. Due to the principle of action at proximity, physical systems are usually massively parallel and only locally connected. Beyond these properties, the wave digital filters are well-known for their excellent numerical stability behavior and their high robustness. The new result of this paper is a synthesis procedure for automatic generation of the algorithms, based on MD wave digital filters for the numerical integration of PDEs describing linear hyperbolic passive systems. The proposed procedure permits a fully automated software development, based on the given partial differential equation.     

Wide Dynamic Range High Output Impedance Current-mode Multifunction Filters with Dual-output Current Conveyors

This paper reports five new single-input multiple-output current-mode multifunction filter circuits which can simultaneously realise three basic filter functions all at high impedance outputs. The circuits employ only the same type of active elements, grounded passive components, andno element matching conditions are imposed. The filters permit orthogonal adjustment of the quality factor Q and angular resonant frequency ω₀. The active/passive sensitivities are shown to be low.     

Log-domain high-order low-pass and band-pass filters

Continuous time current-mode high-order low-pass and band-pass filters based on the log-domain concept are presented in this paper. The passive RLC ladder networks are used as the prototype to achieve the proposed filter by simulating the RLC network synthesis method. The achieved filters have inherited the good sensitivity performance from the RLC passive prototype. Fifth-order RLC ladder low-pass filter and sixth-order RLC ladder band-pass filter are used as prototypes and the signal flow graph (SFG) technique is used for the synthesis. The SFG can identify group of integrators and several signal paths. Log-domain lossy and lossless integrators based on BJT technology are deployed to achieve the integrators for realization of proposed filters. The simulations were carried out and the results exhibited several features which are in agreement with the RLC prototype. The frequency response of filters along 100 kHz to 10 MHz can be electronically tuned through 5–500 µA of bias currents. The THD lower than 1% of LP and BP filters were measured at 10 MHz input. The multi-tone tested was included in the paper for verifying the performance of proposed LP and BP filters. The intermodulation distortions around −50 dB and −60 dB were also investigated for the proposed LP and BP filters.     

New current–mode special function continuous-time active filters employing only OTAs and OPAMPs

This paper reports three current mode second order filters, each of which realizes a specific function without any external passive elements. These filters realize low-pass notch (LPN), high-pass notch (HPN) and all-pass (AP) functions. Two OPAMPs, a double output OTA and a single output OTA are employed for each circuit. The filter structures can be easily cascaded since they have high output impedances. This property is especially useful for achieving high-order filters using these LPN and HPN filters as building blocks. The presented theory is verified with macro models in SPICE simulations and, using the SPICE parameters of the layout technology, post layout simulations are carried out, with parasitics extracted from the layouts of the filter chips.     

Modular log-domain filters realized using wave port terminators

Log-domain wave filters that simulate the passive LC ladder prototype filters are introduced in this paper. The proposed circuits are constructed from the wave equivalents of the reactive elements corresponding to those in the prototype circuit. The wave equivalent circuits are obtained by using a novel log-domain wave port terminator. The wave equivalent of a capacitor in a shunt branch was chosen as an elementary building block for creating high-order filters. The wave equivalent circuits of all other reactive elements in a shunt or in a series-branch connection can be readily obtained using the elementary building block plus some inverters. This way the derived high-order filter configurations are modular. A design example of a third-order elliptic low-pass filter is given, and the performance of the filter was verified by simulation.     

On the practical realization of higher-order filters with fractional stepping

We propose the use of a compact integer-order transfer function approximation of the fractional-order Laplacian operator s^α to realize fractional-step filters. Lowpass and bandpass filters of orders (n+α) and 2(n+α), where n is an integer and 0<α<1, can, respectively, be designed. A 5th-order lowpass filter with fractional steps from 0.1 to 0.9 (i.e. 5.1→5.9) is given as an example with its characteristics compared to 5th- and 6th-order Butterworth filters. Spice simulations and experimental results are shown.     

New universal filter using only current followers as active elements

A new universal current-mode (CM) biquad filter is presented which can realise all the five standard filter functions namely lowpass, bandpass, highpass, notch and allpass employing only unity-gain current followers (CF) as active elements. The workability of the proposed universal biquad, realised with CMOS unity-gain current followers, is established by SPICE simulations. The new circuit provides explicit CM outputs from high output impedance terminals and possesses a number of advantageous features all of which are not available simultaneously in any of the previously reported CF-based universal biquad filters.     

Integrable Current-Mode Filter Realisation using Dual-Output Current Conveyors for Low-Frequency Operation

The realisation criteria of continuous-time current-mode (CM) active filters for low frequency operation are investigated. New lossless and lossy integrators for low frequency operation using dual-output current conveyors (DO-CCII) are proposed. Basing on these building blocks, a CM universal filter with low natural frequencies suitable for integrated circuit implementation is presented. Using the proposed filter, natural frequencies as low as a few ten hertz can be achieved on an integrated circuit chip without using any external passive components. The proposed circuit simultaneously produces three basic filter responses at its high impedance outputs and it has good passive and active sensitivity performance.     

The Application of Particle Swarm Optimization to Passive and Hybrid Active Power Filter Design

This paper proposes an optimal design method for passive power filters (PPFs) and hybrid active power filters (HAPFs) set at high voltage levels to satisfy the requirements of harmonic filtering and reactive power compensation. Multiobjective optimization models for PPF and HAPF were constructed. Detuning effects and faults were also considered by constructing constraints during the optimal process, which improved the reliability and practicability of the designed filters. An effective strategy was adopted to solve the multiobjective optimization problems for the designs of PPF and HAPF. Furthermore, the particle swarm optimization algorithm was developed for searching an optimal solution of planning of filters. An application of the method to an industrial case involving harmonic and reactive power problems indicated the superiority and practicality of the proposed design methods.      

Single DDCC Biquads with High Input Impedance and Minimum Number of Passive Elements

Two new configurations for the design of biquad filters with high input impedance are presented. The first configuration can synthesize low-pass and high-pass filter functions according to the passive components used. The second one can synthesize a band-pass filter function. The proposed configurations employ only one differential difference current conveyor (DDCC) as active elements and minimum number of passive elements, namely two resistors and two capacitors. Another filter topology based on DDCC is presented that allows modifying the quality factor without changing its natural frequency. All the filters enjoy low sensitivities. SPICE simulation results are given to confirm the validity of the analysis and to point out the high performance of the filters.Muhammed A. Ibrahim was born in Erbil, Iraq in 1969. He obtained his B.Sc. and M.Sc. degrees from Salahaddin University, Erbil, Iraq and Istanbul Technical University, Istanbul, Turkey in 1990 and 1999, respectively, all in electronics and communication engineering. Between 1992 and 1996 he worked as Research Assistant at Salahaddin University where he was later appointed as Assistant Lecturer in 1999. Since 2000 he has been studying for his Ph.D. degree in Electronics and Communication Engineering Program at Istanbul Technical University. His main research interests are CMOS circuit design, current-mode circuits and analog signal processing applications. He has more than 20 international journal and conference papers in scientific review.H. Hakan Kuntman received his B.Sc., M.Sc. and Ph.D. degrees from Istanbul Technical University in 1974, 1977 and 1982, respectively. In 1974 he joined the Electronics and Communication Engineering Department of Istanbul Technical University. Since 1993 he is a professor of electronics in the same department. His research interest include design of electronic circuits, modeling of electron devices and electronic systems, active filters, design of analog IC topologies. Dr. Kuntman has authored many publications on modelling and simulation of electron devices and electronic circuits for computer-aided design, analog VLSI design and active circuit design. He is the author or the coauthor of 76 journal papers published or accepted for publishing in international journals, 91 conference papers presented or accepted for presentation in international conferences, 99 turkish conference papers presented in national conferences and 10 books related to the above mentioned areas. Furthermore he advised and completed the work of 7 Ph.D. students and 31 M.Sc. students. Currently, he acts as the head of the Electronics and Communication Engineering Department in Istanbul Technical University. Dr. Kuntman is a member of the Chamber of Turkish Electrical Engineers (EMO).Oguzhan Cicekoglu received the B.Sc. and M.Sc. degrees from Bogazici University and the Ph.D. degree from Istanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996 respectively. He served as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Bogazici University where he held various administrative positions between 1993 and 1999. He served also as part time lecturer at various institutions. He was with the Biomedical Engineering Institute of the Bogazici University between 1999 and 2001. He is currently Associate Professor at the Electrical and Electronics Engineering Department of the same University.His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. Oguzhan Cicekoglu is the author or co-author of 62 journal papers and about 90 international or local conference papers published or accepted for publishing in journals or conference proceedings.He served as the committee member in various scientific conferences and as reviewer in numerous journals including Analog Integrated Circuits and Signal Processing, IEEE CAS-I, IEEE CAS-II, International Journal of Electronics, Microelectronics Journal, Solid State Electronics and IEE Proceedings Pt.G.Oguzhan Cicekoglu is a member of the IEEE.