Analog-digital Systems Research Articles

AN ANALOGUE-DIGITAL CHURCH-TURING THESIS

We argue that dynamical systems involving discrete and continuous data can be modelled by Turing machines with oracles that are physical processes. Using the theory introduced in Beggs et al. [2,3], we consider the scope and limits of polynomial time computations by such systems. We propose a general polynomial time Church-Turing Thesis for feasible computations by analogue-digital systems, having the non-uniform complexity class BPP//log* as theoretical upper bound. We show why BPP//log* should be replace P/poly, which was proposed by Siegelmann for neural nets [23,24]. Then we examine whether other sources of hypercomputation can be found in analogue-digital systems besides the oracle itself. We prove that the higher polytime limit P/poly can be attained via non-computable analogue-digital interface protocols.

The Improvement and Evaluation of an Analog Digital Television System’s Availability and Users Experience

Based on the RGBD sensor, this passage suggested a method named ‘Control-right Management’ to reduce the Interaction Information in order to bring better communication efficiency of an Analog Digital Television System. This system was base on fingertip, dynamic and static hand gesture recognition,and it can be controlled by person in the mid-air. And then split and recombination of different operation elements as “Complex Group Gesture” to improve the system’s availability and users experience. According to the Goals Operators Methods Selection Rules(GOMS) model we analyzed the operation step by step and found the redundant process, then reduce the operation time and steps to give the users better availability and users experience. Calculated by the formula of interaction efficiency, the changed operation showed more efficient than before.Finally we take some experiments of our methods and propose several specialize quantitative evaluation methods that can be used in the field of Digital Television System.

Analog-Digital Power System State Estimation Based on Information Theory—Part II: Implementation and Application

This paper is the second of a two-part series on analog-digital power system state estimation. The minimum-information-loss (MIL) method that calculates an accurate real-time power system model from a set of analog and digital measurements is implemented, applied, and validated. Two MIL implementations are proposed for both power grid and substation state estimation. The performance of the MIL method is evaluated through three tests. First, the success rate of identifying the true topology is statistically quantified for an IEEE 14-bus system and compared with state-of-the-art generalized state estimation (GSE). Then the competitive performance of the MIL method is further substantiated on two real-world test cases that involve the China Eastern power grid in China and a real substation.

SELFLEARNING FUZZY SPIKING NEURAL NETWORK BASED ON DISCRETE SECOND-ORDER CRITICALLY DUMPED RESPONSE UNITS FOR FUZZY CLUSTERING TASKS

Hybrid neural networks based on the idea of combining spiking neural networks and the principles of fuzzy logic are considered. The architecture of self-learning fuzzy spiking neural network based on discrete second-order critically damped response units is proposed. It is proposed to define a spiking neural network in terms of apparatus of classical automatic control theory based on the Laplace transform and z-transform. It is shown that a spiking neural network is a pulse-position threshold detection system based on second-order damped response units. Such kind of description allows using it as an analog-digital system in technical problems solving. The output layer takes firing times of spikes arriving from the second layer, and either performs fuzzy partitioning of the input patterns using probabilistic approach.

Control Laser Spectrofluorimeter with Microcontrollers

For today carrying out of observational measuring and processing of the gained effects without computer technology practically is not available. The importance of using automatic devices becomes more and more obvious. In many cases, when the matter is to work out the experimental devices and methods, there is a problem connected with control of experimental devices and with carrying out automatic measurement. For a solution of this problem experimenters often use different special electric devices which connect experimental devices with computer technologies. For example, such devices are analog-digital (ADC) and digital-analog (DAC) converter systems of electrical circuits etc.

Efficient Spectrum Sharing in the Presence of Multiple Narrowband Interference

In this paper, we study the spectrum usage efficiency by applying wideband methods and systems to the existing analog systems and applications. The essential motivation of this work is to define the prospective coexistence between analog FM and digital Spread Spectrum systems in an efficient way sharing the same frequency band. The potential overlaid Spread Spectrum (SS) system can spectrally coincide within the existing narrowband Frequency Modulated (FM) broadcasting system upon several limitations, originating a key motivation for the use of the FM radio frequency band in many applications, encompassing wireless personal and sensors networks. The performance of the SS system due to the overlaying analog FM system, consisting of multiple narrowband FM stations, is investigated in order to derive the relevant bit error probability and maximum achievable data rates. The SS system uses direct sequence (DS) spreading, through maximal length pseudorandom sequences with long spreading codes. The SS signal is evaluated throughout theoretical and simulation-based performance analysis, for various types of spreading scenarios, for different carrier frequency offset ({\Delta}f) and signal-to-interference ratios, in order to derive valuable results for future developing and planning of an overlay scenario.

Real-time emulation of parallel channel responses in the vertebrate retina and the primary visual cortex

In order to examine the functional roles of visual neurons in the retina and the cortex, responses of neurons to visual stimuli have been investigated physiologically, and discussions have been made using models derived from the physiological experiments. However, these discussions do not necessarily applicable to the case of highly complex visual environments wherein actual biological vision systems operate since they are based on the responses of a limited number of neurons to simple visual stimuli. In order to examine and discuss the functional roles of the neurons, a system that can emulate the responses of a group of model neurons in real time is required. Thus far, a high-speed neural computation emulator with transient response has been developed mainly for engineering applications [1]. In this study, we have developed a system for the real-time reconstruction of neural activities with physiologically reasonable spatiotemporal properties using an analog-digital hybrid system comprised of analog resistive networks, field-programmable gate arrays (FPGA), and a digital computer. The system reconstructs activities of 128 x 128 neurons in each neural layer of the retina and the primary visual cortex at 200 frames per second. The system consists of two retina emulators, a cortex emulator, and a digital computer (Fig.1(A)). The retina emulator emulates both the sustained and transient responses (Fig.1(B)1(C)), and their spike representations (Fig.1(D)1(E)). A part of detailed operation of the retina emulator is written in [2]. The cortex emulator receives spike signals from two retina emulators and emulates responses of cortex neurons including the simple and complex cells. Figure 1 A. Appearance of the system comprised of two retina emulators, a cortex emulator, and a digital computer. B. Sustained response. C. Transient response. D. Sustained response with spike representation. E. Transient response with spike representation.

An Implementation of the L-Estimate Distributions for Analysis of Signals in Heavy-Tailed Noise

An analog–digital system for implementation of the robust time–frequency distributions is proposed. It provides an efficient real-time analysis of nonstationary signals corrupted by heavy-tailed noise. The most important part of this system is the realization of the L-estimate short-time Fourier transform that requires sorting operation. The proposed solution is designed to execute sorting operation within a single clock cycle, regardless of the number of inputs. The performance of the proposed hardware is tested on a real signal example.

A Novel Multi-Exponential Function-based Companding Technique for Uniform Signal Compression over Channels with Limited Dynamic Range

A Novel Multi-Exponential Function-based Companding Technique for Uniform Signal Compression over Channels with Limited Dynamic Range Companding, as a variant of audio level compression, can help reduce the dynamic range of an audio signal. In analog (digital) systems, this can increase the signal-to-noise ratio (signal to quantization noise ratio) achieved during transmission. The μ-law algorithm that is primarily used in the digital telecommunication systems of North America and Japan, adapts a companding scheme that can expand small signals and compress large signals especially at the presence of high peak signals. In this paper, we present a novel multi-exponential companding function that can achieve more uniform compression on both large and small signals so that the relative signal strength over the time is preserved. That is, although larger signals may get considerably compressed, unlike μ-law algorithm, it is guaranteed that these signals after companding will definitely not be smaller than expanded signals that were originally small. Performance of the proposed algorithm is compared with μ-law using real audio signal, and results show that the proposed companding algorithm can achieve much smaller quantization errors with a modest increase in computation time.

Estudo comparativo da qualidade da imagem e do kerma, de entrada e de saída, em simulador de tórax utilizando sistemas analógico e digitalizado CR de aquisição de imagens

OBJETIVO: O processo de migração de sistemas analógicos para digitalizados, para aplicações diagnósticas, requer cuidados específicos, a fim de manter a qualidade das imagens e minimizar a dose no paciente. Este trabalho tem como objetivo analisar e comparar a qualidade da imagem e o kerma num simulador não antropomórfico de tórax gerados por sistemas analógicos e digitalizados CR. MATERIAIS E MÉTODOS: Foram analisados a qualidade da imagem e o kerma, de entrada e saída, no simulador para dois equipamentos de raios X diferentes (Siemens e Emic), com diferentes sistemas de retificação de onda (12 pulsos e alta frequência). Ambos os sistemas (analógico e digitalizado) estavam sendo utilizados no mesmo local. Foram geradas imagens em filme e em image plates. RESULTADOS: Foi observado aumento na tensão e/ou na carga transportada pelo tubo de raios X quando houve a migração para o sistema CR, para manutenção das características diagnósticas da imagem. Isto resultou em aumento de kerma coletado. CONCLUSÃO: As maiores diferenças determinadas (aumento de dose e redução da qualidade da imagem) foram observadas no equipamento com retificação de onda de 12 pulsos e transdutor de imagem CR (image plates).

Shadowed register cell for skew-resistant timing

A shadowed register cell with controllable latency for synthesis of synchronous systems with large clock skewing is presented. Arbitrary delays in clock distribution allow peak supply current reduction in a much wider range than is possibly achieved by means of standard registers. This is put in use to trade clock cycle time for I*R voltage drops and switching noise shaping in mixed analogue-digital systems. The proposed C2MOS cell structure has been implemented with less than 20% area and power overhead compared to the standard register.

Using Work Domain Analysis to Evaluate the Impact of Digitization on Command and Control

This paper introduces a new approach for evaluating the impact of technological change on complex sociotechnical systems. The approach uses Work Domain Analysis as a theoretical base for extracting the key factors that influence system performance. The process has been designed to be expeditious, both in terms of construction and data collection. The approach uses the opinion of subject matter experts to evaluate the impact of each of the abstraction hierarchy nodes on system performance. This approach was used to evaluate the effects of digitization within land based military headquarters, at brigade and battlegroup levels. The proposed approach proved sensitive enough to reveal clear differences between the old analogue and new digital system. The description of the same system at a number of levels of abstraction allows the analyst to develop a high level rating of the system as well as understanding of the key factors that have influenced this opinion.

Bringing Superconductor Digital Technology to the Market Place

The unique properties of superconductivity can be exploited to provide the ultimate in electronic technology for systems such as ultra-precise analogue-to-digital and digital-to-analogue converters, precise DC and AC voltage standards, ultra high speed logic circuits and systems (both digital and hybrid analogue-digital systems), and very high throughput network routers and supercomputers which would have superior electrical performance at lower overall electrical power consumption compared to systems with comparable performance which are fabricated using conventional room temperature technologies. This potential for high performance electronics with reduced power consumption would have a positive impact on slowing the increase in the demand for electrical utility power by the information technology community on the overall electrical power grid. However, before this technology can be successfully brought to the commercial market place, there must be an aggressive investment of resources and funding to develop the required infrastructure needed to yield these high performance superconductor systems, which will be reliable and available at low cost. The author proposes that it will require a concerted effort by the superconductor and cryogenic communities to bring this technology to the commercial market place or make it available for widespread use in scientific instrumentation.

An Improved Instrument for Real-Time Measurement of Blood Flow Velocity in Microvessels

A new approach for the measurement of red blood cell velocity at the level of microcirculation has been developed and characterized. The new real-time and automated measurement system is based on the dual-slit methodology, and blood flow information is extracted from images and transduced into two analog photometric signals and then processed using a hybrid analog-digital system that performs the cross correlation of the signals in real time. The characterization of the system consists of a calibration with a known velocity target, yielding to the hyperbolic calibration curve velocity versus delay and the determination of the velocity detectable range from 0.3 to 120 mm/s. A theoretical study of the measurement uncertainty and parametric studies were carried out to test the system robustness to changes of parameters and to determine the optimal configuration that is applicable to various experimental conditions. The system was further tested in in vivo experiments in the rat cremaster preparation in different types of vessels and flow velocities to verify the consistency of the results, as compared with those from conventional measuring systems. In addition, the dynamic behavior of the system and its response to changes in the measured velocity were studied through a continuous velocity record that was obtained during an experimental procedure.

불확실성을 갖는 비선형 시스템을 위한 퍼지 모델 기반 제어기의 지능형 디지털 재설계

In this paper, we propose a systematic method for intelligent digital redesign of a fuzzy-model-based controller for continuous-time nonlinear system which may also contain system uncertainties. The continuous-time uncertain TS fuzzy model is first contructed to represent the uncertain nonlinear system. A parallel distributed compensation(PDC) technique is then used to design a fuzzy-model-based controller for both stabilization. The designed continuous-time controller is then converted to an equivalent discrete-time controller by using a globally intelligent digital redesign method. This new technique is designed by a global matching of state variables between analog control system and digital control system. This new design technique provides a systematic and effective framework for integration of the fuzzy-model-based control theory and the advanced digital redesign technique for nonlinear systems with uncertainties. Finally, Chaotic Lorenz system is used as an illustrative example to show the effectiveness and the feasibility of the developed design method.

Statistical Method for Analog-to-Digital System Testing in Time and Spectral Domain

The article deals with an improved method for testing analog-digital system (ADS) as the system objects with the dynamic nonlinear and stochastic properties. A proposed technique makes it possible to utilize the statistical testing method to estimate the dynamic of ADS as in time, as in spectral domain, without the use of additional hardware or the need for additional measurements. The implementation of the statistical testing method that is described is based on a broadband test signal that simulates actual operating conditions. The technique makes it possible to avoid the standard problems associated with precise estimation of the spectrum of a broadband signal. It has been validated in tests of the dynamic parameters of 6 up to 1-bit high-speed.

ANALYSIS OF MOBILE TELEPHONY DEVELOPMENT IN CROATIA

Mobile telephony appeared in 1955 and its development inthe world and in Croatia can be divided into two generations:analogue mobile system and digital mobile systems. Mobile te/eplzony is a part of the telecommunication market experiencingthe fastest growth. Already in 1990, the mobile telephonesaccounted for 4% of the world market in telecommunicationservices, and their share is increasing daily. Liberalisation ofthe Croatian market of mobile telephony was a necessity for establishingcompetition as a necessG/y prerequisite for providinghigh-quality se1vices and reducing their prices, and it COJTespondsto the mobile telephony system development worldwide.At the beginning of the 90s, the Republic of Croatia was laggingbehind the telecommunication-developed world, and today shehas a modem infrastructure that supports highly sophisticatedse1vices by two digital and one analogue mobile telephone network.

Point-to-point connectivity between neuromorphic chips using address events

This paper discusses connectivity between neuromorphic chips, which use the timing of fixed-height fixed-width pulses to encode information. Address-events (log/sub 2/(N)-bit packets that uniquely identify one of N neurons) are used to transmit these pulses in real time on a random-access time-multiplexed communication channel. Activity is assumed to consist of neuronal ensembles-spikes clustered in space and in time. This paper quantifies tradeoffs faced in allocating bandwidth, granting access, and queuing, as well as throughput requirements, and concludes that an arbitered channel design is the best choice. The arbitered channel is implemented with a formal design methodology for asynchronous digital VLSI CMOS systems, after introducing the reader to this top-down synthesis technique. Following the evolution of three generations of designs, it is shown how the overhead of arbitrating, and encoding and decoding, can be reduced in area (from N to /spl radic/N) by organizing neurons into rows and columns, and reduced in time (from log/sub 2/(N) to 2) by exploiting locality in the arbiter tree and in the row-column architecture, and clustered activity. Throughput is boosted by pipelining and by reading spikes in parallel. Simple techniques that reduce crosstalk in these mixed analog-digital systems are described.

Hybrid Motion Simulation Using High-Speed Parallel-Link Robot.

A new kind of motion simulation is proposed for the purpose of simulating complicated motions such as those caused by interactions between objects in special environments (e.g., those of micro-gravity). The motion simulation is based on a hybrid simulation : consisting of a combined analog-digital system. Hence it has functions of real-time numerical simulation and embedding a physical model in the simulation. In addition, the motion simulation is equipped with flexibility of modeling, effective human interface and scalability of system. Finally, as a preliminary experiment, motion caused by interaction between two simplified free-flying space robots has been simulated with a prototype of the hybrid motion simulator.

Efficient techniques for accurate modeling and simulation of substrate coupling in mixed-signal IC's

Industry trends aimed at integrating higher levels of circuit functionality have triggered a proliferation of mixed analog-digital systems. Magnified noise coupling through the common chip substrate has made the design and verification of such systems an increasingly difficult task. In this paper we present a fast eigendecomposition technique that accelerates operator application in BEM methods and avoids the dense-matrix storage while taking all of the substrate boundary effects into account explicitly. This technique can be used for accurate and efficient modeling of substrate coupling effects in mixed-signal integrated circuits.