Implantable stimulator and recording device for artificial prosthesis control

This paper presents an application-specific integrated circuit (ASIC) consisting of both, a four-channel neural stimulator and a single-channel recording amplifier, along with their digital control and regulated voltage supplies. The ASIC has been designed to be compatible with different types of electrodes although the use of sieve electrodes was considered a priority. The main performances of this ASIC as stimulator are: fully programmability for several stimuli shapes (monophasic, biphasic, arbitrary amplitude/duration pairs for stimulation and recovery phases), wide frequency range (7 Hz to more than 350 Hz with 1 Hz resolution) and high-current range ( in two scales, with 6 bits resolution). Furthermore, any anode can be associated with any cathode, thus improving the spatial selectivity of some electrode types. From the recording viewpoint, the ASIC exhibits very low noise , high CMRR (94 dB) and digitally programmable gain and bandwidth. The overall digital control is designed to control up to 16 stimulation channels and four recording amplifiers using a regular and modular implementation for the analog parts which gives rise to higher ASIC performances with a small increase in area. The system has been integrated using high voltage CMOS technology. “In vitro” experimental results are also presented.     

A theory on constructing a hyper-acuity electronic device

The vision system can differentiate a misalignment of two lines up to 1/10 of photoreceptor size (called hyper-acuity), even though its retinas are moving randomly. Over the last few decades, several theories have been proposed to explain this phenomenon. Using computer simulation, it is shown that a device can be built to achieve hyper-acuity. The study also reveals several interesting insights.     

An architecture for a configurable mixed-signal device

The mixed-signal programmable system-on-chip (PSOC) architecture for high-volume low-cost applications is presented. Programmable analog, digital, and clocking circuits are combined with flash memory and a microcontroller to provide a platform for single-chip solutions for low-cost consumer applications. Both programmable analog and digital circuits are designed to support a moderate level of abstraction, balancing flexibility against cost and performance. A rough comparison of alternative approaches based on functionality and cost is presented.     

A direct electronic Fourier transform device for imaging

A novel device employing elastophotoconductivity in CdS to create electronic signals representing the spatial Fourier transform of an image is described.     

A phased-array stimulator system for studying planar and curved cardiac activation wavefronts

Wavefront propagation in cardiac tissue is affected greatly by the geometry of the wavefront. We describe a computer-controlled stimulator system that creates reproducible wavefronts of a predetermined shape and orientation for the investigation of the effects of wavefront geometry. We conducted demonstration experiments on isolated perfused rabbit hearts, which were stained with the voltage-sensitive dye, di-4-ANEPPS. The wavefronts were imaged using a laser and a charge-coupled device (CCD) camera. The stimulator and imaging systems have been used to characterize the relationship between wavefront velocity and fiber orientation. This approach has potential applications in investigating curvature effects, testing numerical models of cardiac tissue, and creating complex wavefronts using one-, two-, or three-dimensional electrode arrays.     

电子器件用中温钎料的研究进展

从中温钎料的基本性能要求出发,综述了中温(400~600℃)钎料的发展历程和近年来中温钎料的最新研究进展。指出由超细焊粉制备的焊膏是今后中温钎料发展的一个重要方向。     

运动视觉跟踪电子设备的改进设计

针对运动视觉跟踪电子设备跟踪运动目标效果差的问题,提出一种运动视觉跟踪电子设备的改进方案。在传统的运动视觉跟踪电子设备基础上,引进了蒙特卡罗算法,并且修改了接收函数,使得跟踪运算过程中补偿了由于计算上的误差所导致的跟踪效果差的问题,根据运动视觉误差补偿方法构建了相对应的数学模型,有效地解决了传统运动视觉跟踪电子设备跟踪运动目标效果差的问题。通过仿真实验可以有效的证明,该方案能够有效地解决跟踪运动目标效果差的问题。     

The trap-controlled transistor: a persistent electronic or optoelectronic device

It is noted that semiconductor defect-induced trap states can be regarded as atomic-sized charge storage elements. Two types of junction field-effect transistor are proposed which use trap occupation to modulate the channel width. Trap occupation may be controlled either electronically or optically, giving device characteristics that are determined by the specific properties of the defect responsible for the trap level. Potential applications include very-high-density dynamic, static or nonvolatile memories, integrating optical detectors, and wavelength-selective optoelectronic switches.     

基于单片机的心率监测和分析系统设计

文章设计了一款实用的人体心率脉搏测量显示装置,下位机通过单片机采集心率传感器发出的脉搏信号,上位机利用功能强大的虚拟仪器LabVIEW设计出脉搏信号的采集与分析系统,对心率的测定提供精准、形象的画面,可为医生分析人体健康情况提供重要的参考.     

An adaptive gating approach for X-ray dose reduction during cardiac interventional procedures

The increasing number of cardiac interventional procedures has resulted in a tremendous increase in the absorbed X-ray dose by radiologists as well as patients. A new method is presented for X-ray dose reduction which utilizes adaptive tube pulse-rate scheduling in pulsed fluoroscopic systems. In current pulsed systems, the X-ray tube is pulsed at a fixed rate of 30 pulses/sec (or higher) and an image is formed at the end of each pulse. In the proposed system, pulse-rate scheduling depends on the heart muscle activity phase determined through continuous guided segmentation of the patient's electrocardiogram (ECG). Displaying images generated at the proposed adaptive nonuniform rate is visually unacceptable; therefore, a frame-filling approach is devised to ensure a 30 frame/sec display rate. The authors adopted two approaches for the frame-filling portion of the system depending on the imaging mode used in the procedure. During cine-mode imaging (high X-ray dose), collected image frame-to-frame pixel motion is estimated using a pel-recursive algorithm followed by motion-based pixel interpolation to estimate the frames necessary to increase the rate to 30 frames/sec. The other frame-filling approach is adopted during fluoro-mode imaging (low X-ray dose), characterized by low signal-to-noise ratio images. This approach consists of simply holding the last collected frame for as many frames as necessary to maintain the real-time display rate. Results of simulated system performance on an image sequence from a diagnostic study of left ventricular volume produced an average of approximately 3:1 dose reduction without compromising the diagnostic quality of the generated images. The adaptive pulsed-progressive system concept is viewed as the next evolutionary step in X-ray fluoroscopic systems.     

An electronic controller for adaptive suspension

Developing an adaptive suspension system for a luxury car weighing over 2000 kg presents an exacting challenge in embedded control. This article describes the development of an adaptive suspension controller by Lamerholm Fleming Ltd for Rolls-Royce Motor Cars Ltd. during the period from 1995 to 1997. The controller replaced an earlier design, which had originally entered production in 1989. The new system uses hydraulic dampers (shock absorbers) which can be switched between three different settings by means of two solenoid controlled valves. Each damper setting provides a different complex force/velocity response for bounce and rebound. These mechanical characteristics are determined by the precise magnitudes of springs and orifices within the damper. The function of the electronic controller is to select the optimum damper setting for any particular driving conditions and to choose the best time to switch from one setting to another. The aim of the whole suspension system is to provide the best possible compromise between ride, comfort and handling     

An enhanced fast handover triggering mechanism for Fast Proxy Mobile IPv6

Handover delay performance is a critical issue to support real-time applications in wireless networks. To address this issue, this paper presents an Enhanced fast handover Triggering Mechanism (ETM) to improve the handover performance of mobile nodes (MNs) in Fast Proxy Mobile IPv6 (FPMIPv6). Making use of the information from the link layer, the ETM predicts two cases that the MNs perform in the reactive handover mode. Then, it establishes the bi-directional tunnel in advance for fast handover. As a result, the reactive handover delay is significantly reduced. Integrating the ETM into FPMIPv6 forms an enhanced Fast Proxy Mobile IPv6 (eFPMIPv6) protocol. Simulation experiments show that with the presented ETM mechanism, the eFPMIPv6 outperforms the original FPMIPv6 in terms of the overall handover performance.     

一种环保型电子封装用复合材料

以平均粒径10 μm高纯Si颗粒为增强体,以A1-Si20为基体,采用挤压铸造专利技术制备体积分数为65%的高体积分数环保型Sip/A1-Si20复合材料.试验结果表明:复合材料的铸态组织均匀、致密,没有明显的颗粒团聚和偏聚,也不存在微小的孔洞和明显的缺陷;Sip/A1-Si20是轻质(密度为2.4 g/cm3)、低膨胀(7.77×10-6/℃)、高导热(156.34W/m.℃)复合材料,电导率为4.08 MS/m,具有较高的比模量和比强度,可以对其进行镀Ni和封装焊接,能较好的满足电子封装和热控器件的使用要求.     

An accurate model for a depletion mode IGFET used as a load device

An accurate model has been described for an n-channel, silicon gate, depletion mode insulated gate field effect transitor (IGFET), in configuration most often used in LSI design (V_GS=OV). The model is derived from basic semiconductor charge analysis, approximating the profile of the redistributed implanted impurities in the channel. Excellent agreement with experimental results is shown. This model has the potential to accurately predict the charge capacity behavior in storage cells, in very high density random access memories, where “pseudo depletion mode” devices are used.     

浅谈电子元器件生产中的无铅手工焊

无铅焊接存在润湿性较差、温度较高、氧化速度快等缺点。在工艺上需严格控制焊接温度和时间,才能保证焊接质量。     

A new algorithm for simulation of power electronic systems usingpiecewise-linear device models

This paper describes a new algorithm for simulation of power electronic systems. Piecewise-linear (PWL) approximation is used to model nonlinear components, including switching devices, nonlinear reactive components, and nonlinear control circuitry. A representation of PWL elements is constructed such that a constant system matrix is obtained, regardless of the states of PWL elements. An efficient method for state determination is proposed, which is capable of resolving difficulties caused by discontinuous characteristics of PWL elements. The resulting simulation algorithm is quite general, requires no prior knowledge of the circuit operation, is void of convergence problems, and yields relatively short simulation times on desktop PC machines     

An integrated hybrid device for binary-phase-shift-keyingsubcarrier modulation

We propose an integrated optical/radio frequency (RF) hybrid device for binary-phase-shift-keying subcarrier modulation that is based on optical amplitude modulation and interference with phase delay. The device consists of two multiple-quantum-well (MQW) electroabsorption (EA) modulators branched with two multimode interference (MMI) couplers. When an RF carrier was applied to one modulator and a digital signal to the other one, the phase modulation of the RF subcarrier was realized     

An upper limit for high power switching with a polymer currentlimiter device

The high power electrical switching properties of a polymer current limiter device configured to switch at only one electrical contact are studied as a function of applied voltage. It is shown that a dramatic change in switching behavior occurs at a characteristic voltage. Below this voltage, the device switches to a high resistance state whereas at higher applied voltages it does not. It is shown that the high voltage, low resistance state has similar electrical characteristics to an arc discharge and a qualitative model for the state is proposed. Material variation experiments are also described which demonstrate that the voltage at which the observed change in switching behavior occurs depends sensitively on the composite material composition and fabrication parameters