一种新型过载传感器的数字化设计

针对以往输出模拟信号的过载传感器传输稳定性差、抗干扰性差、操作不便等问题,提出了一种可实现数字信号输出的新型过载传感器。选用基于MEMS技术的电容式加速度计实现对过载信号的高精度采集,信号经调理电路后通过STM32微处理器内部的模数转换模块处理数据,采用RS-485通信总线实现数字信号的传输,最终实现过载参量的灵敏采集和数字信号输出。实验证明,该传感器在性能可靠性及功能完整性方面均满足设计要求。     

Speech-transmission performance of p.c.m. systems

A method is described for calculating a quantity representative of the transmission performance of a p.c.m. system. The value obtained depends upon (a) the number of quantised output voltage states, (b) the companding law and (c) the volume of the input speech signal relative to the overload point of the system.     

Delta modulation with slope-overload prediction

An improved delta-modulation system is described which uses a delay line to obtain information about the `future? behaviour of the input signal. Conditions of potential slope overload are detected before the signal is encoded and the encoding pattern altered accordingly. Computer simulation results show that signal/noise ratios can be 3 dB better than for simple delta modulation.     

Overload vector quantisation by selective shell projection inlattice VQ

An efficient overload vector quantisation algorithm is proposed for lattice vector quantisation (LVQ). It selects a projection shell for each overload vector by changing its scaled position along the radial direction to the origin in the truncated lattice and obtains the adjusted overload scaling factor for dequantisation from the orthogonality principle. Experimental results show that this algorithm achieves a good performance in signal to quantisation noise ratio (SQNR) over the conventional algorithm using a single projection of the overload vector on the external shell     

Quantization Noise in ADPCM Systems

The system considered here consists of a differential pulse-code modulator (DPCM) in which the quantizer is replaced by an adaptive quantizer. Adaptation is accomplished by adjusting the stepsize at every sampling instant, depending upon the magnitude of the quantization error. Quantizing noise in adaptive DPCM (ADPCM) systems falls into three categories: granularity, slope overload, and quantizer saturation. Granular noise occurs because only a finite number of levels are available to represent the analog input signal during the encoding process. Slope overload happens when the slope of the input signal increases faster than the adaptive system can follow. Quantizer saturation exists because nonoptimal decisions on step-size adjustments can lead to situations in which quantizer overload occurs without slope overload. The result is an error larger than a purely granular noise analysis would suggest. Equations for the three types of quantizing noise in ADPCM systems are derived, and computer simulations are perforated. For flatand RC-filtered Gaussian input signals, oversampled at various rates, the simulation results agree well with theoretical predictions. Comparisons indicate that the ADPCM can perform better than the best analogous nonadaptive system in terms of signal-to-quantizing-noise ratio. Furthermore, the optimal operating point for the ADPCM is much less sensitive to changes in input signal parameters and system component values than in nonadaptive systems.     

Interstage network to control overload in cascaded continuous-time /spl Sigma//spl Delta/ modulators

An improved interstage network suitable for avoiding overload and for increasing the signal-to-noise ratio in low-oversampling-ratio cascaded continuous-time SigmaDelta modulators is reported. Feedforward coefficients, going from the input signal to the second stage, are used to control overload without affecting the behaviour of the noise cancellation filters. Moreover, the anti-aliasing functionality is preserved. Simulation results show the utility of the proposed network in terms of the overload performance     

子母弹抛撒冲击过载测试方法

为了准确测量子母弹子弹爆炸抛撒时的冲击过载,文中设计了一种可置于子弹内部或充当子弹的抛撒测试仪,并分析了仪器功能和特点。经实验表明:该方法在抛撒实验时可以很好地完成冲击过载数据采集和存储。最后,利用小波处理及频谱和模态分析相结合的数据处理方法,分析了数据的有效性和正确性。     

Running average error reduces overload noise in delayed delta-modulation systems

A simple but effective method to reduce overload noise and improve the overall performance in delta-modulation (DM) systems is presented in this paper. Two identical DM encoders operate on a different time-basis in such a manner that a running average of the error signal from the first encoder is taken into consideration by the second one. The resulting operation is a time adaptation process yielding diminished overload noise during overload bursts. Results obtained by computer simulation for speech signals show an overall signal-to-quantization noise ratio (SQNR) improvement up to 2.5 dB at optimum step size over classical schemes.     

Calculation of distribution function of ringing power in telephoneexchange

An exact calculation of the minimum required power of a ringing signal generator in a telephone exchange is presented. The problem of power calculation is treated as a traffic problem. As can be seen, the required ringing power is a function of the traffic parameters of subscribers, the electrical characteristics of the telephone lines and sets, and the allowed overload time     

Adaptive 2nd-order delta-modulation system with 1-bit memory

A system of companding is described, as applied to a 2nd-order delta-modulation system, which has a memory of only one sampling interval, leading to a fast response to overload, and improvement in dynamic range and signal/noise ratio.     

On SCP Overload Control in Mobile Intelligent Network Based on Queue Size

1IntroductionIntelligent network,an affiliated network over com-munication network,is introduced for the quick provi-sion of newservices[1 ~2].In the structure of intelligentnetwork,a Service Control Point(SCP) serves a lot ofService Switch Point(SSPs)[3 ~4].It is a veryi mportanttopic that howto guarantee the Qos of SCP (e .g.thenumber of successfully processed calls per unit ti me)whenthe network becomes overloadedinthis centralizednetwork structure . There were many studies about the…     

复合压力传感器研制

为满足行业配套组件的发展需求,研制了一种新型复合压力传感器。该传感器采用分体结构设计,将压力信号转换成深度信号,利用精密的信号处理电路,将微弱的深度信号进行放大、比较等处理,可同时输出连续量电信号和阶跃量信号。该传感器具有精度、过载倍数和可靠性高,温度系数小,耐腐蚀等特点,整体性能均高于单一功能类的产品。     

弹体侵彻中加速度计的机械滤波仿真研究

利用ANSYS/LS-DYNA软件对弹体侵彻混凝土靶板过程中,不同的机械滤波材料滤波能力进行了仿真分析。研究了应用于加速度传感器的不同滤波材料对加速度激励信号的影响,分析结果显示,0.5cm厚低密度聚乙烯材料在弹体侵彻混凝土靶板中可以起到较好的机械滤波器的作用,达到了对高过载环境下加速度计的滤波、保护目的。     

掺铒光纤放大器的增益锁定

本文从掺铒光纤放大器的速率方程理论模型出发、根据光功率传输方程，对多个WDM信道传输时EDFA动态特性进行了模拟分析。提出了以某一路信道进行反馈从而实现增益锁定的方案，模拟计算结果表明，当EDFA的输入功率不超过形成激光振荡所容许的最大输入功率时，以某一路信道信号光进行反馈可以实现增益的稳定锁定；增益锁定作用的时间响应相当快，达到稳态增益锁定值的时间小于5ms；当上下信道或信道功率变化时，增益锁定仍然十分有效。     

基于PSD的药柱位移测试系统的研究

榴弹水平发射时会产生高轴向过载环境,推进剂药柱在此环境中长度收缩变形产生过载位移。而Position Sensitive Device（PSD）是基于横向光电效应的光电位置敏感器件,具有位置分辨率高,响应速度快,处理电路简单等优点。文章就一维PSD位移测量原理和相关特点,以FPGA主控模块为核心,集信号调理、采集存储等功能于一体,创新性的设计了传感器与壳体一体化测量系统。文章就测试系统各个模块进行了说明并对测量数据进行了处理分析,采用多项式拟合曲线,提高了系统的测量精度;经过高过载实验,验证了系统的可靠性和稳定性,为药柱位移测试评估方法的建立提供了可靠的实验数据。     

一种具有过流保护功能的振荡器设计

提出了一种用于峰值电流模式控制的高压BUCK变换器的振荡器,并具有特殊电流限保护功能。在BUCK变换器正常工作时,该振荡器提供频率为340KHz的时钟信号;当振荡器处于异常状态,如负载过重或输出电压较低时,振荡器频率会随着输出电压的降低逐渐减小,该振荡器可以有效地防止电流失控现象的发生,并且减小了在异常情况时系统的功耗,同时也克服了功率管在电流过大时烧毁的危险;另外该振荡器还提供具有前沿消隐功能的斜坡补偿信号。该电路是基于CSMC的0.6μm 25V BCD工艺实现的,并通过电路模拟软件Hspice对振荡器电路完成了仿真验证。     

Designing for learnability in human-robot communication

In a future scenario where many devices can be controlled using the voice, easy and intuitive access will be crucial for avoiding cognitive overload when users are faced with many different systems and interaction models. We propose a model for interaction with spoken language interfaces applied to heterogeneous tasks for service robots, based on the idea of using a family of lifelike characters. We argue that we can signal important features of the speech interface by using certain visual cues. The aim is to facilitate learning and transfer between interfaces. We discuss challenges for dialogue design affecting learnability in the light of the speech interface constructed for our full-scale robot prototype CERO.     

Direct-feedback coders: Design and performance with television signals

Direct-feedback coding is a refinement on the well-known differential coding method. Two filters are used at the transmitter of a direct-feedback coder; one connected in series with the input and the other in the forward path of a feedback loop that contains the quantizer. The first filter preemphasizes the signal and determines the overload characteristic of the coder; the other filter shapes the quantization noise and sets the stability of the feedback. At the receiver a filter reconstitutes the signal spectrum and deemphasizes the noise. For television the preemphasis should he a short time-constant differentiator, the deemphasis a short time integrator, and the feedback filter a long time integrator. Conventional differential coders use a single filter in the feedback path both to provide preemphasis and to shape the feedback characteristic, so the design is a compromise. Compared with direct-feedback coding they usually have less feedback gain and a larger time constant in the preemphasis and deemphasis, consequently, the contouring noise is more visible and the streaking caused by transmission error is longer. Although only application to television is considered, the methods have wider use. General formulae are given for the output noise and optimum filter characteristics; they take into account signal spectra, frequency weighting for noise, sampling rate, quantization step size, and an overload parameter. Measurements on real coders, operating on TV signals, and digital simulations confirm the results.     

Recent Advances in Calcium-Based Anticancer Nanomaterials Exploiting Calcium Overload to Trigger Cell Apoptosis

Calcium ion is vital for the regulation of many cellular functions and serves as a second messenger in the signal transduction pathways. Once the intracellular Ca²⁺ level exceeds the tolerance of cells (called Ca²⁺ overload), oxidative stress, mitochondrial damage, and cell/mitochondria apoptosis happen. Therefore, Ca²⁺ overload has started to be deeply exploited as a new strategy for cancer therapy due to its high efficiency and satisfactory safety. This review aims to highlight the recent development of Ca²⁺-based nanomaterials (such as Ca₃(PO₄)₂, CaCO₃, CaO₂, CaH₂, CaS, and others) able to trigger intracellular Ca²⁺ overload and apoptosis in cancer therapy. The intracellular mechanisms of varied Ca²⁺-based nanomaterials and the different types of strategies to enhance Ca²⁺ overload are discussed in detail. Moreover, the design of more efficient Ca²⁺ overload-mediated cancer therapies is prospected mainly based on 1) the enhanced cellular uptake by surface modification and morphology optimization of nanomaterials, 2) the accelerated Ca²⁺ release from nanomaterials by increasing the intracellular H⁺ level and by photothermal effect, and 3) the overload maintenance by Ca²⁺ efflux inhibition, Ca²⁺ influx promotion, or promoting Ca²⁺ release from the endoplasmic reticulum.     

An improved monolithic instrumentation amplifier

The design of an instrumentation amplifier fabricated using monolithic thin-film-on-silicon bipolar processing is described. The circuit features input as well as output overload protection, internal compensation, and improved noise and drift performance. A novel method of input-output signal coupling is described, which does not depend on tracking current sources, and provides a high degree of isolation for all but the desired signal components. The circuit is described in detail, and the layout techniques used to minimize thermal interaction are outlined. Finally, the performance of the circuit as typified by several production lots is reported.