基于反向遍历组合单元BDD的延时参数激励波形自动生成算法

本文研究了深亚微米工艺条件下单元特征参数提取和建模的激励生成,提出了一种基于反向遍历组合单元BDD的延时参数激励波形生成算法。该算法通过分析组合单元延时参数激励波形的特征和单元BDD的特征,推导了组合单元延时激励波形的生成定理,给出了基于该定理的组合单元延时激励波形生成算法。算法能快速完备地生成延时参数的激励波形,避免了复杂的布尔函数运算,提高了激励波形的生成效率。

数字多波束逐点聚焦延时参数的压缩算法

针对数字多波束合成技术在超声成像领域应用中存在逐点聚焦延时参数的存储容量过大的问题,提出了一种四波束逐点聚焦延时参数的压缩存储与实时生成算法。首先将四波束的聚焦延时问题转换成单波束的聚焦延时问题,然后对转换后的单波束聚焦延时数据进行量化、压缩和存储。在聚焦时,将压缩存储的延时参数进行解压,实时生成四波束所需的延时参数。以8通道128阵元的平阵探头为例,对该算法进行了相关的数学推导和证明,并对其性能进行了分析讨论,验证了该算法的优越性。

时间敏感网络延时组成的精确分析与测量方法

在依据时间敏感网络(time-sensitive networking, TSN)标准估算相邻节点之间的最大传输延迟Δt时,将不可避免地引入额外的无效等待时间,这种等待时间被称为“泡沫延时”。分析了泡沫延时对增加端到端延时和降低规划成功率的负面影响,并通过细粒度地分析Δt的延时组成,首次提出Δt的精确测量方法。基于精确的Δt,消除了TSN规划时产生的泡沫延时。基于两款定制的TSN交换设备搭建了真实的测试环境,测试结果显示,泡沫延时至少占端到端延时的26.4%,并且消除泡沫延时后规划成功率提升了8.9%~39.1%。

合并单元内部延时故障对主变保护的影响

合并单元是智能变电站广泛应用于电气量采集、处理及输出的设备,随着智能变电站自动化技术的发展,对合并单元的功能和性能要求越来越高,其内部参数的隐蔽性也使现场缺陷分析变得更难发现。分析了一起500kV智能变电站CSD-602合并单元内部延时故障引起的主变保护动作告警事故。通过现场调取录波报文分析,并结合二次CT回路连接结构,发现公共绕组CT回路电流存在相角异常情况,最终判定CSD-602合并单元内部延时故障导致差动电流增大引起主变保护动作告警。通过事故反推演和仿真分析,进一步证明了CSD-602合并单元内部延时故障这一隐蔽性问题造成主变保护动作告警。

浅析回声仪定标延时的改正

简述回声仪定标延时的改正数的推求,并同测某一水下地形,分别采用SDH-13D、SDH-13A回声仪定标延时绘出地形图,进行改正前后等高线走势和断面数据的比较.

自适应参数型多径时延估计方法的研究

在考虑多通道非平稳信号干扰及背景噪声的情况下 ,提出了基于自适应参数型时间延时估计方法。该方法能准确地进行多径传输情况下的时间延时估计 ,有效地抑制干扰和噪声的影响。仿真结果说明了该方法的有效性。

单片机技术在时间继电器测试中的应用

介绍时间继电器延时参数的测试,单片机测试框图以及软件流程。另外对检测的外围线路以及对在检测过程中的电磁兼容EMC问题也进行了相关介绍和说明。

台阶爆破工业电子雷管精确延时爆破设计与应用

为了充分发挥工业电子雷管延时精度高、网路设计灵活的优势,基于现场试验和理论分析开展了台阶爆破工业电子雷管延时参数设计方法的研究。针对爆破振动控制,提出了基于多目标振动控制的延时参数设计方法;针对爆破破碎优化,提出了基于等间隔短延时的延时参数设计方法。在此基础上开发了工业电子雷管智能起爆系统,大幅提高现场联网施工效率。结果表明,针对爆破破碎优化,单位孔距最优延时时间为0.8~2.5 ms/m,硬岩和脆性岩体的最优单位孔距延时时间的取值窗口范围更窄。针对爆破振动控制,当孔间延时间隔较小时,群孔振动峰值随着延时间隔增大而迅速衰减,随着延时间隔进一步增大,振动强度呈现锯齿形起伏变化。研究成果验证了工业电子雷管精确延时爆破设计方法的合理性,可为工业电子雷管的爆破参数优化提供参考依据。

单片机技术在时间继电器测试中的应用

介绍了时间继电器延时参数的测试,并对单片机测试框图及其软件流程进行了相应介绍。此外,对检测的外围线路以及在检测过程中的电磁兼容EMC问题进行了相关介绍和说明。

SUBSAMPLE TIME DELAY ESTIMATION BASED ON PHASE SPECTRUM OF BAND LIMITED STOCHASTIC SIGNALS

The accuracy of conventional time delay estimation （TDE） algorithms is limited by the sampling interval. A novel algorithm of subsample TDE suitable for widehand signals is presented to improve the accuracy. This algorithm applies periodogram and parabolic interpolation to the cross correlation spectrum of band limited stochastic signals, and can obtain a continuous time delay estimator. Simulations are carried out to compare the performance of the proposed algorithm with that of other subsample TDE algorithms. Results show that the proposed algorithm outperforms other algorithms and reachs the Cramer-Rao lower bound （CRLB） at a high signal- to-noise ratio. For the wideband characteristic and the randomness of the transmitting signal, the proposed algo- rithm is suitable for the low probability of intercept radars.

Guaranteed cost sampled-data control for uncertain nonlinear time-varying delay system

The robust guaranteed cost sampled-data control was studied for a class of uncertain nonlinear systems with time-varying delay. The parameter uncertainties are time-varying norm-bounded and appear in both the state and the input control matrices. By applying an input delay approach, the system was transformed into a continuous time-delay system. Attention was focused on the design of a robust guaranteed cost sampled-data control law which guarantees that the closed-loop system is asymptotically stable and the quadratic performance index is less than a certain bound for all admissible uncertainties. By applying Lyapunov stability theory, the theorems were derived to provide sufficient conditions for the existence of robust guaranteed cost sampled-data control law in the form of linear matrix inequalities (LMIs), especially an optimal state-feedback guaranteed cost sampled-data control law which ensures the minimization of the guaranteed cost was given. The effectiveness of the proposed method was illustrated by a simulation example with the asymptotically stable curves of system state under the initial condition of x(0)=[0.679 6 0].

Stabilization of a class of nonlinear discrete time systems with time varying delay

The stability and stabilization of a class of nonlinear discrete time delayed systems(NDTDS) with time-varying delay and norm-bounded nonlinearity are investigated. Based on discrete time Lyapunov–Krasovskii functional method, a sufficient delaydependent condition for asymptotic stability of nonlinear systems is offered. Then, this condition is used to design a new efficient delayed state feedback controller(DSFC) for stabilization of such systems. These conditions are in the linear matrix inequality(LMI) framework. Illustrative examples confirm the improvement of the proposed approach over the similar cases. Furthermore, the obtained stability and stabilization conditions will be extended to uncertain discrete time delayed systems(UDTDS) with polytopic parameter uncertainties and also with norm-bounded parameter uncertainties.

An accurate calculation method of the power harmonic parameters based on the delay time theorem of Fourier transform

A new accurate calculation method of electric power harmonic parameters was presented. Based on the delay time theorem of Fourier transform, the frequency of the electric power was calculated, and then, suing interpolation in the frequency domain of the windows, the parameters （amplitude and phase） of each harmonic frequency signals were calculated accurately. In the paper, the effect of the delay time and the windows on the electric power harmonic calculation accuracy was analysed. The digital simulation and the physical measurement tests show that the proposed method is effective and has more advantages than other methods which are based on multipoint interpolation especially in calculation time cost; therefore, it is very suitable to be used in the single chip DSP micro-processor.

On Stabilizing Sets of PI Controllers for Multiple Time Delayed Process

This paper considers the problem of stabilizing multiple time delayed processes using proportional integral(PI) controller.The presented approach is based on finding all possible values of control parameters which will result in pure imaginary roots of closed loop characteristic equation under all process parameters fixed.The ergodic search of three PI control parameters are converted from the range of infinity to finite range by introducing trigonometric tangent function.After all possible stability boundaries are obtained,the Nyquist stability method is used to determine the actual stability region of the controller parameters.This method also permits design for simultaneous minimum gain and phase margin requirement.An illustrative example case is also presented.

MILD Combustion for Hydrogen and Syngas at Elevated Pressures

As gas recirculation constitutes a fundamental condition for the realization of MILD combustion, it is necessary to determine gas recirculation ratio before designing MILD combustor. MILD combustion model with gas recirculation was used in this simulation work to evaluate the effect of fuel type and pressure on threshold gas recirculation ratio of MILD mode. Ignition delay time is also an important design parameter for gas turbine combustor, this parameter is kinetically studied to analyze the effect of pressure on MILD mixture ignition. Threshold gas recirculation ratio of hydrogen MILD combustion changes slightly and is nearly equal to that of 10 MJ/Nm3syngas in the pressure range of 1-19 atm, under the conditions of 298 K fresh reactant temperature and 1373 K exhaust gas temperature, indicating that MILD regime is fuel flexible. Ignition delay calculation results show that pressure has a negative effect on ignition delay time of 10 MJ/Nm3syngas MILD mixture, because OH mole fraction in MILD mixture drops down as pressure increases, resulting in the delay of the oxidation process.