Probability of error in CPSK systems with intersymbol interference and additive noise

A simple lower bound, an upper bound and a simple approximation to the upper bound on the probability of error for coherent phase-shift-keyed (CPSK) systems operating in the presence of intersymbol interference and additive noise are obtained. The additive noises in the in-phase channel and the quadrature channel are assumed to be independent, and are independent of the signal, but not restricted to be Gaussian. The approximation to the upper bound is four times the lower bound, hence the tightness of these bounds is uniform for all cases. This fact and the simplicity of the bounds make these bounds a useful system design tool. Numerical examples for quaternary and octonary systems are presented and compared to known results.     

Output regulation control for stochastic systems with additive noise

This paper investigates the robust output regulation problem for stochastic systems with additive noises. As is known, for the output regulation control problem, a general method is to regard that the system is disturbed by an autonomous exosystem (which is consisted by external disturbances and reference signals), and for the system disturbed by the white noise, the stochastic differential equations (SDEs) should be utilized in modeling, accordingly, a controller with a feedforward regulator is constructed for the stochastic system with an exosystem, which can not only cancel the external disturbance, but also transform the trajectory tracking problem into the stabilization problem; In consideration of the state variables in stochastic systems cannot be measured completely, we embed an observer to the controller, such that the random interference can be suppressed, and the trajectory tracking can be achieved. Based on the stochastic control theory, the criteria of the exponential practical stability in the mean square is presented for the closed-loop system, finally, through tuning the controller parameters, the mean square of the tracking error can converge to an arbitrarily small neighborhood of the origin.     

The time-delay digital tanlock loop: performance analysis in additive Gaussian noise

Recently, a new non-uniform sampling digital phase-locked loop, the time-delay digital tanlock loop (TDTL), has been proposed. We have analyzed in a previous work the first- and second-order TDTLs under noise-free conditions. In this work, we analyze the performance of the TDTL in the presence of additive Gaussian noise for different values of the loop parameters. It is shown that the expected value of the steady-state phase errors at the input and the output of the phase error detector are equal to the noise-free steady-state values, while the variance is significantly reduced when the signal-to-noise ratio is increased or the phase shift introduced by the time-delay approaches 90°. The locking ranges of the TDTL parameters under noise-free conditions are unchanged by the presence of noise.     

Stochastic error simulation method of fiber optic gyros based on performance indicators

Gyro simulation is an important process of inertial navigation theory research, with the major difficulty being the stochastic error modeling. One commonly used stochastic model for a fiber optic gyro (FOG) is a Gaussian white (GW) noise plus a first order Markov process. The model parameters are usually obtained by using time series analysis methods or the Allan variance method through FOG static experiment. However, in a real life situation, a FOG may not be used. In this paper, a simulation method is proposed for estimating the stochastic errors of FOG. When using this method, the model parameters are set based on performance indicators, which are chosen as the angle random walk (ARW) and bias stability. During the research, the ARW and bias stability indicators of the GW noise and the first order Markov process are analyzed separately. Their analytical expressions are derived to reveal the relation between the model parameters and performance indicators. In order to verify the theory, a large number of simulations were carried out. The results show that the statistical performance indicators of the simulated signals are consistent with the theory. Furthermore, a simulation of a VG951 FOG is designed in this research. The Allan variance curve of the simulated signal is in agreement with the real one.     

光纤测温预警系统在火电厂消防报警系统中的应用

光纤感测温预警系统是较不常见的消防探测系统,电厂消防是典型的工程,本文将两者结合形成一个典型设计。     

Probability of outlier analysis in weak GPS signal acquisition

In this paper, global positioning system (GPS) signal acquisition is investigated under weak signal conditions, when a catastrophic deterioration in performance begins to occur causing outliers to happen in range estimation. The paper compares conventional detection techniques in GPS signal acquisition. The theoretical probability of outlier is derived for GPS Gold code and compared to the probability of outlier using Monte Carlo simulation. In addition, the theoretical probability of outlier for coherent detection technique is also derived. A novel binary hypothesis test is introduced which is used to generate a new set of curves to analyze the performance of detectors in weak signal conditions.     

Asymptotic memoryless detection of random signals in dependent noise

Design of detectors for strong mixing signals in strong mixing noise is considered, where a large degree of dependency may occur between the signal and noise. Under the criterion of asymptotic relative efficiency, it is shown that this design reduces to determining the solution of an integral equation, where only knowledge of the second order statistics of the randon processes involved is required. In particular, if the signal is independent of the noise and has nonzero mean, the optimal detector is the same as in the known constant signal case. It is also shown that it is possible to delete several regularity conditions which may be difficult to check in practice in the slightly more restrictive case where the maximal correlation coefficients of the signal and noise tend to zero.     

Orthogonal-polynomials-based integral inequality and its applications to systems with additive time-varying delays

Recently, a polynomials-based integral inequality was proposed by extending the Moon’s inequality into a generic formulation. By imposing certain structures on the slack matrices of this integral inequality, this paper proposes an orthogonal-polynomials-based integral inequality which has lower computational burden than the polynomials-based integral inequality while maintaining the same conservatism. Further, this paper provides notes on relations among recent general integral inequalities constructed with arbitrary degree polynomials. In these notes, it is shown that the proposed integral inequality is superior to the Bessel–Legendre (B–L) inequality and the polynomials-based integral inequality in terms of the conservatism and computational burden, respectively. Moreover, the effectiveness of the proposed method is demonstrated by an illustrative example of stability analysis for systems with additive time-varying delays.     

Expected power bound and stability of two-dimensional digital filters with multiplicative noise in the FMLSS model

This paper studies the two-dimensional (2-D) expected power bound (EPB) for 2-D digital filters with multiplicative noise in the Fornasini-Marchesini local state-space (FMLSS) model. By virtue of a class of linear matrix inequalities (LMIs), the novel existence criterion of 2-D EPB for 2-D digital filters in the considered model is obtained. The corresponding stabilization controller design method is presented based on the above criterion. Finally, two examples are presented to verify the effectiveness of our results.     

The role of digital identifier systems in the theory of digital objects

Theory of Digital Objects (TDO) can be considered as one of the important theories for explaining distinctive attributes and social practices of digital objects. The main aim of this study is to determine the role and position of digital identifiers and digital identifier systems in social practices of TDO. Results of applying comparative evaluation method demonstrated that the digital identifier systems can be considered as a third approach called identifiable Web, among memorable and navigable web in TDO. Moreover functions, technologically-induced tensions, challenges, counter mechanisms and emerging practices of the proposed approach had been investigated in contrast with the two existing social practices approaches. Results of this study could provide new ideas to administrators and researchers of these systems for promoting them from the sociotechnical aspect.     

Model conversion and digital redesign of singular systems

Design procedures are proposed for model conversion and digital redesign of a singular system, which is controllable at finite and impulsive modes. In order to attain a standard regular problem, we use some techniques to decompose the singular system into a reduced-order regular subsystem and a nondynamic subsystem. As a result, some well-known design methodologies for a regular system can be applied to the reduced-order regular subsystem. Finally, we transform the results obtained back to those of the original coordinate system.     

Performance degradation due to measurement noise in control systems with disturbance observers and saturating actuators

Augmenting feedback control systems with disturbance observer (DOB) is a widely used technique in system design to compensate for the effect of exogenous disturbances as well as plant model uncertainties. In practice, actuator saturation should be taken into account in the design of control systems with DOB. In such cases, we have observed performance degradation due to zero mean measurement noise in the form of tracking loss. This phenomenon has never been reported in DOB literature. This paper reports the phenomenon, analyzes the conditions under which the tracking loss occurs, and also presents design guidelines to avoid the tracking loss. Experimental verification is also provided using a BLDC motor drive testbed.     

Stability independent and dependent of delay for delay differential systems

We provide new proofs to modified equivalent conditions for stability independent of delay of retarded and neutral delay differential systems. We also present a new test procedure for stability independent of delay. If the system is not stable independent of delay, the test is further applicable to obtain the intervals of delay for which the system is asymptotically stable. The usefulness and simplicity of the new test procedure is illustrated by numerical examples.     

基于数字电视信号传输与控制的测试系统设计

本系统结构简单、设计合理、使用方便,稳定性好,成本低廉。经实践证明本设计克服现有系统复杂、成本高的缺点,达到了设计要求。     

Mean-square consensus of hybrid multi-agent systems with noise and nonlinear terms over jointly connected topologies

This paper studies the mean-square consensus of second-order hybrid multi-agent systems over jointly connected topologies. Systems with time-varying delay and multiplicative noise are considered. The date sampling control technique is adopted. Through matrix transformation, a positive definite matrix transformed by the Laplacian matrix is obtained, where the Laplacian matrix is a connected subgraph divided by the jointly connected topologies. By using graph theory, matrix theory and Lyapunov stability theory, sufficient conditions and the upper bound of time delays for the mean-square consensus are obtained. Finally, several simulations are presented to demonstrate the validity of the control method.     

Stabilization and destabilization of nonlinear systems via intermittent stochastic noise with application to memristor-based system

This paper considers the stabilization and destabilization of a given nonlinear system by an intermittent Brownian noise perturbation. We give some distinct conditions and conclusions on almost sure exponential stability and instability, which are related to the control period T and the noise width δ. These results are then exploited to examine stabilization and destabilization via intermittent stochastic perturbation and applied to the stabilization of a memristor-based chaotic system. Two numerical examples are presented to illustrate the theoretical results.     

数字信号处理中常用的matlab工具箱函数简介

本文就数字信号处理中所涉及到的一些典型MATLAB工具箱函数进行了简要的介绍，希望能为专门从事数字信号处理的人士，在使用MATLAB这门应用性工具方面，提供一些适当的帮助。     

On the optimality of hysteresis operators in signal processing and communication systems

This paper demonstrates that hysteresis operators are the optimal estimators for a large class of estimation and decision problems. This class of problems arises whenever a cost is associated with actions needed to process changes in the estimates or decisions. A simple example related to least-squares estimation is used to illustrate and motivate the developments in this paper. Subsequently, the problem of mean-square estimation with minimal cost of actions is investigated. These results provide a justification for the use of hysteresis in many practical signal processing and communication applications.