Application of Binary Filters in Automated Counting of Reticulocytes

Computer generated binary matched filters have been used in an attempt to recognize and count immature red blood cells (reticulocytes) on a standard blood smear slide in a coherent optical data processing system. The Fourier plane binary filters were synthesized on a digital computer using an appropriate polar geometry mathematical model. Various filters were constructed and tested for synthetic blood cells, and preliminary test results are presented for random samples of actual blood slides. These show a trend of manual reticulocyte count versus the matched filter count, but no statistical significance.     

一种基于Casorati-奇异值分解的超快平面波超声多普勒自适应时空域杂波抑制算法

超快超声平面波成像技术实现了超声的高帧频大视野同步采集，捕捉到更多有效原始信息，而传统滤波器在处理这种大视野数据方面有诸多不足。该文基于Casorati奇异值分解(Casorati-SVD)技术提出一种改进的自适应杂波抑制算法:首先，选取一个区域的原始平面波数据构建Casorati数据矩阵并进行奇异值分解；其次，根据分解后分量的多普勒频率和能量自适应匹配合适的滤波截止参数，抑制组织杂波和噪声并提取血流信号；最后，对每个区域重复前面的步骤并统计所有输出获取最终图像。该文分别在仿体、人体手臂动脉和家兔脑血流的回波信号上验证该算法抑制杂波的能力，这些实验结果表明，相比全局Casorati奇异值分解滤波器，这种改进的分区域自适应滤波算法将信噪比(SNR)提高4.4%～50%，对比信噪比(CNR)提高4.7%～55.9%。该技术实现了多普勒血流成像的空间自适应滤波，对临床血流成像的发展有重要意义。     

An improved PID switching control strategy for type 1 diabetes

In order for an "artificial pancreas" to become a reality for ambulatory use, a practical closed-loop control strategy must be developed and validated. In this paper, an improved PID control strategy for blood glucose control is proposed and critically evaluated in silico using a physiologic model of Hovorka et al. [1]. The key features of the proposed control strategy are: 1) a switching strategy for initiating PID control after a meal and insulin bolus; 2) a novel time-varying setpoint trajectory; 3) noise and derivative filters to reduce sensitivity to sensor noise; and 4) a practical controller tuning strategy. Simulation results demonstrate that proposed control strategy compares favorably to alternatives for realistic conditions that include meal challenges, incorrect carbohydrate meal estimates, changes in insulin sensitivity, and measurement noise.     

基于滑动窗口的LRU大流检测算法

由于高速链路中的流量测量缺乏可扩展性且高速链路中及时准确的识别大流对网络测量、控制和管理有重要的意义,且在高速链路中能有效、合理的利用有限的资源,是解决资源紧缺的有效方法,基于此提出一种基于滑动窗口的资源可控的LRU淘汰机制大流量测量算法。通过"滑动窗口"机制,实现流大小的无偏估计,然后采用LRU的思想过滤小流、检测大流。仿真实验证明该算法的可行性。     

Dynamic erbium-doped fiber amplifier based on active gainflattening with fiber acoustooptic tunable filters

We describe the first demonstration of a dynamic erbium-doped fiber amplifier (EDFA) based on automatic feedback control of active gain equalizing filters. The filters are all-fiber acoustooptic tunable filters capable of generating controllable filter shapes. Wide dynamic-range gain/power control is achieved with <0.6-dB signal ripple over 30 nm in various operating conditions. We also show, by numerical simulation, an important advantage of the dynamic EDFA over a conventional EDFA in cascaded structures     

Plate with piezoelectric actuators/sensors

This paper investigates the robust control of low-frequency modes of a thin all-clamped plate with piezoelectric actuators and sensors. Locations of the actuators and sensors are important in reducing the spillover effects of uncontrolled modes. Locations good for controlling the low-frequency modes are evaluated by using the modal shapes. The uncertainties at the high-frequency region and the low-frequency region around the frequency zero should be considered for the stability of the control system. These two uncertainties can limit the gain of the vibration controller. Low-pass filters and high-pass filters are introduced to alleviate the high-frequency and the low-frequency uncertainty, respectively. The linear quadratic Gaussian (LQG) control with the low-pass filters and high-pass filters is demonstrated to suppress the first three modes of an all-clamped plate and gives 10~20-dB reduction of vibration in the experiment. Also, the highest gains of the controller for the plant, which consists of the nominal model and several uncontrolled modes, are evaluated to vindicate the usefulness of high-pass filters     

频域反卷积滤波器的因果性的研究

本文首先介绍了成功应用于现代时域测量中的几种频域反卷积滤波器.并说明了这些反卷积滤波器元旦是非因果的.显然,滤波器非因果化要影响反卷积的估值,因此,对反卷积滤波器进行因果化是很必要的.进而,介绍了将这些反卷积滤波器因果化原理和方法,并给出了因果化的流程图.最后,对常用的反卷积滤波器的因果化进行了仿真研究,分别给出了这些反卷积滤波器困晨化前后的滤波效果.仿真结果表明,因果化的滤波器可改善反卷积的估值.     

Log-domain wave filters

A systematic method for designing log-domain wave filters is presented. Wave filters simulate topologically and functionally passive doubly terminated LC ladder prototype filters of low sensitivity. The design in the log-domain is based on a transposition of the signal flow graph (SFG) that corresponds to the wave equivalent of elementary two-port blocks in the linear domain, to the corresponding log-domain SFG. This is achieved by using an appropriate set of complementary operators, in order to preserve the linear operation of the whole circuit. Simulation results of a fifth-order low-pass and a fourth-order bandpass log-domain wave filter are given, using HSPICE. The proposed circuits are suitable for low-voltage operation and in high-frequency applications.     

A Novel Diversity-Controlled Genetic Algorithm for Rapid Optimization of Bandpass FRM FIR Digital Filters Over CSD Multiplier Coefficient Space

The conventional frequency response masking (FRM) approach is one of the most well-known techniques for the design of sharp transition band finite impulse response (FIR) digital filters. The resulting FRM digital filters permit efficient hardware implementations due to an inherently large number of zero-valued multiplier coefficients. The hardware complexity of these digital filters can further be reduced by representing the remaining (non-zero) multiplier coefficient values by using their canonical signed-digit (CSD) representations. This paper presents a novel diversity-controlled (DC) genetic algorithm (GA) for the discrete optimization of bandpass FRM FIR digital filters over the CSD multiplier coefficient space. The resulting bandpass FIR digital filters are permitted to have equal or unequal lower and upper transition bandwidths. The proposed DCGA is based on an indexed look-up table of permissible CSD multiplier coefficients such that their indices form a closed set under the genetic operations of crossover and mutation. The salient advantage of DCGA over the conventional GA lies in the external control over population diversity and parent selection, giving rise to a rapid convergence to an optimal solution. The external control is achieved through the judicious choice of a pair of DCGA optimization parameters. An empirical investigation is undertaken for choosing appropriate values for these control parameters. The convergence speed advantages of the DCGA are demonstrated through its application to the design and optimization of a pair of bandpass FRM FIR digital filters with equal or arbitrary lower and upper transition bandwidths. In both cases, an increase of about an order of magnitude in the speed of convergence is achieved as compared to the conventional GAs.     

Current-mode high-order OTA-C filters

A new way to implement current-mode continuous-time filters is presented which uses operational transconductance amplifiers (OTAs). Based on the simulation of a signal flow graph on the all-pole lowpass transfer function, the two current-mode realizations of high-order OTA-C filters are obtained.     

Efficient implementation of tunable ladder filters using multi-output current controlled conveyors

A methodology to realize continuous-time current-mode tunable ladder filters of any order has been presented. This proposed technique individually simulates signal flow graph (SFG) of each branch element from passive filter prototype using only multi-output second generation current controlled conveyors (MCCCIIs) and grounded capacitors. This leads to simple structure, ease of design and suitability for IC fabrication. A third-order Butterworth low-pass filter, a third-order elliptic low-pass filter and a sixth-order Chebyshev band-pass filter are employed to demonstrate the proposed realization scheme. These simulated filters retain minimum requirement of passive and active elements and provide the filter corner frequency tunability. Moreover, the method allows an implementation of the elliptic filters by simply adding floating capacitors to all-pole filter structures.     

One-cycle control of three-phase active power filter with vector operation

Active power filters (APFs) provides an effective measure to eliminate the power line harmonic/reactive currents generated by nonlinear loads or by distributed energy sources that are connected to the grid. Active power filters are typically connected in parallel to the harmonic/reactive current sources and cancel the harmonic/reactive components in the line current so that the current flow into and from the grid is sinusoidal and in phase with the grid voltage. Since the APFs process only the harmonic/reactive power, their power-handling capability can be much higher than that of the cascade power-factor-correction methods. In this paper, the one-cycle control method is extended to control three-phase APFs. The proposed control approach employs one integrator with reset along with several logic and linear components to control a voltage-source converter to achieve three-phase unity power factor for the current to and from the power grid. No multipliers or sensors for the load current and the APF inductor current are required. Furthermore, there is no need to calculate the reference for controlling APF inductor current so that complicated digital computation is eliminated. The operation switching frequency is constant that is desirable for industrial applications. The proposed control approach features great simplicity, excellent harmonic/reactive current cancellation, and solid stability. It is a cost-effective solution for power quality control for electronic equipment, buildings, industrial facilities, ships, airplanes, distributed power generation stations, etc. All findings are supported by experimental results.     

Continuous Cardiac Output Measurement: Aspects of Doppler Frequency Analysis

From the suprasternal notch blood flow velocity in the aorta can be measured non-invasively by a Doppler probe. Integration over systole after frequency analysis gives a measure of stroke volume if a separate diameter observation is incorporated. Frequency analysis by a zero crossing counter or by a set of parallel phaselock loops was less effective than a set of bandpass filters. Observations on dogs, baboons and humans before and after exercise or surgery suggest the indications to be useful. Application to judging heart failure by the effect of introducing a volume load is indicated. Changes in output also are measured in freely moving subjects.     

用信流图法设计n阶CCⅡ电流模式滤波器

提出了用信流图设计ｎ阶ＣＣⅡ（第二代电流传输器）电流模式低通滤波器的方法。该滤波器由具有双输出端的第二代电流传输器（ＣＣⅡ±）和同相第二代电流传输器（ＣＣⅡ＋）及接地ＲＣ元件构成。与同类电路［４］比较,设计更简便,结构更简单。ＲＣ元件全部接地,便于集成。     

基于多输出端电流模式全差分积分器的梯形滤波器实现

本文提出了利用低电压多输出端电流模式全差分积分器（MCDI）综合连续时间电流模式滤波器的方法。首先对所设计的无源梯形滤波器用信号流图形（SFG）进行综合，然后用MCDI实现该SFG，分析并模拟了MCDI及所提出的滤波器的特性，应用3.3V、0.5μm、CMOS工艺参数仿真得到的1dB波纹四阶Chebyshev低通滤波器功耗仅为1mW左右，且其截止频率可在很宽的范围内调控，此外，这种滤波器还具有结构简单，对称性好，失真小等优点，适于全集成。     

MOSFET-Only filter design automation based on polynomial regression with exemplary circuits

In this work, a novel design automation method is presented for easy construction of MOSFET-Only or MOSFET-C filters. In contrast to previous works in the literature, the proposed algorithm is simple since it uses polynomial fitting models obtained from SPICE data in order to reformulate small signal parameters and some DC characteristics of MOSFET’s. Polynomial regressive models facilitate to interact between design constraints (power, area, speed, pole frequency etc.) and design variables (operating voltages, currents and device dimensions). In this regard, two novel agile MOSFET-Only filters produced with the proposed automation process are presented in order to qualify the automation flow. The produced filters are simulated in LT-SPICE and CADENCE-SPECTRE environment by using 0.18 µm TSMC technology. These agile filters can easily be used in a wide range of applications such as encrypted communications or very high frequency circuits. In addition, it is shown that there is a good agreement between proposed design automation flow and simulations.     

Design of Low-Pass Elliptic Filters by Means of Cascaded Microstrip Rectangular Elements

A new method for synthesizing nonredundant low-pass elliptic filters in a microstrip configuration is presented. The realization consists of the cascade connection of proper rectangular elements, each one corresponding to four reactive elements of the lumped-constant prototype. This allows an effective control of parasitic and unwanted reactance which results in the possibility of realizing higher order filters with cutoff frequencies up to X-band. Fifth- and seventh-order filters were fabricated on alumina substrates showing very good performance, particularly in the passband.     

Design of microstrip quadruplet filters with source-load coupling

Quadruplet microstrip filters with source-load coupling are proposed to achieve similar skirt selectivity and/or in-band flat group delay as that of a sixth-order canonical form or an extracted pole microstrip filter. The diagnosis method of unwanted effects such as asynchronous resonant frequencies and unwanted couplings, which often occurs in the microstrip's open environment, is described in detail. A systematic design flow to implement a quadruplet microstrip source-load coupled filter with proper filter response is also provided. Two trial filters exhibited quasi-elliptical and flat group-delay response are designed and fabricated. Both theoretical and experimental results are presented.     

广义Chebyshev最优滤波器设计

本文论证了等波纹广义Chebyshev函数滤波器的最优化特性,提出了由设计指标得到广义Chebyshev函数的方法,并且引入信号流图非常简便的得到了对应网络的拓扑结构,最终完成滤波器的设计.本文对具有带外传输零点的滤波器设计具有相当重要的意义.     

Automated design of switched-current filters

This paper describes the automated design and synthesis of switched-current (SI) filters using SCADS, a flexible CAD system integrated in a major VLSI design suite. With this system, the nonspecialist can produce high performance analog filters suitable for mixed signal CMOS IC's fabricated using only standard digital processes. To achieve high levels of performance on silicon, filter designs are realized using an enhanced differential circuit technique (S²I) in its integrators and sample-and-hold cells. The design system is described in terms of the embedded circuits, its integrated tool set, the filter design flow and the engineering procedures for ensuring reliable circuit operation. Examples of high performance video frequency filters are presented, each generated automatically by SCADS within one day. Fabricated in a 0.8 μm standard CMOS process, they demonstrate state-of-the-art performance