INTRODUCTION TO DIGITAL SYSTEMS ENGINEERING

Modern society life is inextricably linked with the digital environment. A consequence is the transformation of ergatic systems into digital ones. The result is the emergence of new types of man-machine interaction. The essential feature of such interaction is to minimise human involvement in the ergatic system functioning. According to this, the issues of organising the safe and effective functioning of digital ergatic systems have priority importance. In this regard, the aim was to study the features of man-machine interaction in an actual digital ergatic system. We chose an ergatic system for research. The main elements of the system were students (70 people of the first-year study) and teachers (5 people) of the Simon Kuznets Kharkiv National University of Economics, as well as the digital system “Personal training systems the Simon Kuznets Kharkiv National University of Economics” (PTS). This digital system is an adapted model of the Moodle digital system. The study found out that the key components that determine the safety and efficiency of the digital ergatic system are the operator's digital mindset, digital tools and digital devices. The study of these components in the system made it possible to establish that it had a balanced state. It is substantiated the optimal form of man-machine interaction in the system. It is mixed learning. It is shown that the tendency to minimise the human role in a digital ergatic system does not always have the expected positive result, which determines the need for further research on this issue. In addition, we analysed the difficulties arising in the design of digital systems. The main reason for this is a lack of developers awareness of the ergonomic and cognitive aspects of man-machine interaction. It is shown that the development of critical thinking and intuition in students is closely related to the individual trajectory of learning. For this, it is essential to update interdisciplinary knowledge. In this case, it is necessary to familiarise students with current concepts and system-forming principles, which are the basis of human factors engineering. It was substantiated that the application of current concepts and system-forming principles in training will allow optimising man-machine interaction. The positive results will be evidence even at the stage of designing digital systems

A digital wide-band system for damping ring instabilities in an accelerator is presented. With increased beam intensity, the losses of an accumulator ring tend to increase due to the onset of various instabilities in the beam. An analog feedback damper system has been implemented at Los Alamos National Laboratory. This analog system, while functional, has certain limitations and a lack of programmability, which can be overcome by a digital solution. A digital feedback damper system is being designed through a collaborative effort by researchers at Oakridge National Laboratory, Los Alamos National Laboratory, and the University of Wisconsin. This system, which includes analog-to-digital converters, field programmable gate arrays and digital-to-analog converters can equalize errors inherent to analog systems, such as dispersion due to amplifiers/cables, gain mismatches, and timing adjustments. The digital system features programmable gains and delays, and programmable equalizers that are implemented using digital FIR and comb filters. The flexibility of the digital system allows it to be customized to implement different configurations and extended to address other diagnostic problems.

The NRC recognizes that a more complete technical basis for understanding and regulating advanced digital technologies in commercial nuclear power plants is needed. A concern is that the introduction of digital safety systems may have an impact on risk. There is currently no standard methodology for measuring digital system reliability. A tool currently used to evaluate NPP risk in analog systems is the probabilistic risk assessment (PRA). The use of this tool to evaluate the digital system risk was considered to be a potential methodology for determining the risk. To test this hypothesis, it was decided to perform a limited PRA on a single dominant accident sequence. However, a review of existing human reliability analysis (HRA) methods showed that they were inadequate to analyze systems utilizing digital technology. A four step process was used to adapt existing HRA methodologies to digital environments and to develop new techniques. The HRA methods were then used to analyze an NPP that had undergone a backfit to digital technology in order to determine, as a first step, whether the methods were effective. The very small-break loss of coolant accident sequence was analyzed to determine whether the upgrade to the Eagle-21 process protection system had an effect on risk. The analysis of the very small-break LOCA documented in the Sequoyah PRA was used as the basis of the analysis. The analysis of the results of the HRA showed that the mean human error probabilities for the Eagle-21 PPS were slightly less than those for the analog system it replaced. One important observation from the analysis is that the operators have increased confidence steming from the better level of control provided by the digital system. The analysis of the PRA results, which included the human error component and the Eagle-21 PPS, disclosed that the reactor protection system had a higher failure rate than the analog system, although the difference was not statistically significant.

2 - Digital Voice Fundamentals

We often hear that we live in a digital age. This refers to the massive adoption of computer systems within every aspect of our lives from smart phones to automobiles to household appliances. This statement also refers to the transformation that has occurred to our telecommunications infrastructure that now transmits voice, video, and data using 1’s and 0’s. There are a variety of reasons that digital systems have become so prevalent in our lives. In order to understand these reasons, it is good to start with an understanding of what a digital system is and how it compares to its counterpart, the analog system. The goal of this chapter is to provide an understanding of the basic principles of analog and digital systems.

The addition operation is required by any digital, analogue, or control system. The speed and accuracy with which the digital system operates is dependent on the functioning of adders. Adders are utilised in a variety of logical and arithmetic procedures. The goal of VLSI system design research is to improve the performance of digital systems, hence there is a strong incentive to examine and analyse adder architectures. The purpose here is to understand the family of faster adders available, such as the Ripple Carry Adder, Carry Look Ahead Adder, Carry Select Adder, and so on. This paper is about the Kogge Stone Adder in the 18nm FinFET model's technology node. It has a high PDP because it operates at a faster rate than its competitors. The adder is designed and built for bit lengths of 4 and 8, with random input data simulations used to evaluate its operations. Criteria such as power, performance, area, gate count, and PDP are used to construct a comparison. Every block used to construct the adder is inspected, and the results are graphically shown. In order to properly examine the parameters, the acquired data is tabulated.

Begun in 2001 with a total budget of around $100M, the Expanded Very Large Array (EVLA) project is the only major upgrade to the VLA undertaken since the interferometer was dedicated in 1980. The goal of this 11-year long project is to improve all the observational capabilities of the original VLA - except for collecting area and spatial resolution - by at least an order of magnitude. To achieve this, the 28 VLA antennas have been modernized with new digital data transmission systems that link to a new, wideband, fiber optic digital LO/IF system, and eight new sets of cooled receivers are under construction that will offer full frequency coverage from 1 to 50 GHz, with instantaneous bandwidths up to 8 GHz provided by two independent dual polarization frequency pairs. The new WIDAR correlator provided by NRAO's Canadian EVLA partner replaced the old VLA correlator in early 2010 and is currently undergoing commissioning. The long duration of the EVLA construction project coupled with the need to maintain the scientific productivity and user base of the telescope obviously precluded shutting down the old array while new infrastructure was built and commissioned. Consequently, the construction plan was based on the fundamental assumption that the old VLA would continue to operate as new EVLA capabilities gradually came online; in some cases, additional complexity had to be designed into new hardware in order to maintain transitional interoperability between the old analog and new digital systems as the latter were installed and commissioned. As construction has advanced, operations has increasingly had to coexist side by side with EVLA commissioning and verification. Current commissioning plans attempt to balance making new EVLA capabilities available to the user community as soon as they have been installed and verified, and maintaining a stable and robust end-to-end data acquisition and delivery process for the user community.

A series of structural vibration control experiments and related theory are developed to check the effectiveness of analog and digital control system with piezoelectric material sensors and actuators. Velocity feedback analog control has been tried for the cantilever beam with PZT (lead-zirconate-titanate) wafer sensors and actuators. To improve the control system, steady- state quadratic optimal control algorithm using a digital micro-computer has been used. To apply optimal control algorithms, signals sensed by partially distributed sensors were converted to point concept signals like those from conventional displacement or velocity sensors. Actuating voltage signals were then synthesized from point force output signals. This paper presents excellent results for structural vibration control using both analog and digital systems.

Verification of either analog or digital systems is known to be difficult. Verifying modern mixed-signal systems increases the complexity further. This paper presents a range based approach to verify mixed-signal systems including parameter variation by a single simulation run. Analog systems are simulated by a SPICE-like simulator which uses a special range arithmetic, called affine arithmetic. The simulation of digital systems is extended to include the earliest and latest possible arrival times for every signal. Special converters transform the signals between each domain. The speed-up of this framework compared to traditional Monte-Carlo simulations was up to 500.

Digital communication is a kind of method that carrier is applied to digital signal for transmitting message, or uses digital signal to carry on digital modulation to the carrier and transmits the communication mode. Digital signals such as telegraph, digital data, and analog signals such as voice and image that have been digitally processed can be transmitted. Besides, since the rapid development of modern technology such as computer technology, digital storage technology, digital switching technology and digital processing technology, many signals at equipment and terminal interface are digital signals, hence it is convenient to connect it with the digital communication system. Anyway, the purpose of this project is to use MATLAB programming to construct a digital communication system, demonstrates the results of its operation and analysis eleven different factors may affect the communication of the system. All the functions of different sections are separated and named in their own file with its annotation. The comparisons of results that are influenced by different factors are well explained through figures or tables. All the efforts are targeted to minimize the error between input file and output file to build a qualified digital communication system and prove more useful data for the reference of this field.

Three different pulse processing systems coupled to a tissue-equivalent proportional counter were tested in performance for various neutron and gamma-ray dose rates. The three systems used are a conventional analogue system, a real time system and a digital pulse processing system. The Tandetron accelerator at the McMaster Accelerator Laboratory was used to produce a mixed neutron-gamma field via the 7Li(p,n) reaction. The proton energy ranged from 1.8 to 2.5 MeV with the current set at 100, 200 and 300 muA. The digital system displayed the fastest pulse processing speed. Microdosimetric spectra from the three systems were consistent and both neutron and gamma-ray dose rates showed good agreement in most cases. At neutron dose rates higher than 20 mGy/min the data from the digital system was reliable while systematic deviations were observed for the other two systems.

The analogue and digital notational systems for documenting choreographic movement provide alternative strategies for spatial design. These strategies overlap architectural design and dance choreography to explore reciprocal exchanges regarding the body, geometry and methods of spatial notation. Analogue and digital notational systems are compared to illustrate a change where the notation is fed back to the performer and used as inspiration for further iterative performances. Whilst the use of analogue notation systems supports the criterion of fundamental design, they have limitations which are overcome with the use of flexible digital systems that more readily adapt to change and interrelate to a dancer’s intentions for movement creation. Performance-driven fabrication explores the practical application of this process. Two stages of ‘Performance-driven design’ and ‘Data-driven fabrication’ are combined, resulting in a spatial design and construction system that incorporates interactivity between human and robotic performers.

Frequency stabilization for external cavity diode laser has played an important role in physics research. Many laser frequency locking solutions have been proposed by researchers. Traditionally, the locking process was accomplished by analog system, which has fast feedback control response speed. However, analog system is susceptible to the effects of environment. In order to improve the automation level and reliability of the frequency stabilization system, we take a grating-feedback external cavity diode laser as the laser source and set up a digital frequency stabilization system based on National Instrument’s FPGA (NI FPGA). The system consists of a saturated absorption frequency stabilization of beam path, a differential photoelectric detector, a NI FPGA board and a host computer. Many functions, such as piezoelectric transducer (PZT) sweeping, atomic saturation absorption signal acquisition, signal peak identification, error signal obtaining and laser PZT voltage feedback controlling, are totally completed by LabVIEW FPGA program. Compared with the analog system, the system built by the logic gate circuits, performs stable and reliable. User interface programmed by LabVIEW is friendly. Besides, benefited from the characteristics of reconfiguration, the LabVIEW program is good at transplanting in other NI FPGA boards. Most of all, the system periodically checks the error signal. Once the abnormal error signal is detected, FPGA will restart frequency stabilization process without manual control. Through detecting the fluctuation of error signal of the atomic saturation absorption spectrum line in the frequency locking state, we can infer that the laser frequency stability can reach 1MHz.

Cellular nonlinear/neural networks (CNN's) are one of the analog systems that is hard to emulate or simulate on digital systems. It is known that CNN systems are linear for Gabor-type spatial filters. Although it is possible to represent the state equations of the discrete CNN in matrix notation, it is almost impossible to implement the huge state matrix on a digital system without optimization. In this paper some well known linear equation solving methods are optimized for CNN and required computational powers and memories are compared.

A system of scholarly monograph publishing, primarily under the auspices of university presses, coalesced only 50 years ago as part of the final stage of the professionalization of US institutions of higher education. The resulting analogue publishing system supplied the authorized print monographs that academic institutions newly required for faculty tenure and promotion. That publishing system – as each of its components – was bounded, stable, identifiable, well ordered, and well policed. As successive financial shocks battered both the country in general and scholarly publishing in particular, just a decade after its final formation, the analogue system went into extended decline. Finally, it is now giving way to a digital scholarly publishing system whose configuration and components are still obscure and in flux, but whose epistemological bases differ from the analogue system in almost all important respects: it will be relatively unbounded and stochastic, composed of units that are inherently amorphous and shape shifting, and marked by contested authorization of diverse content. This digitally driven, epistemic system shift in scholarly publishing may well be an extended work in progress, since the doomed analogue system is still fiscally dominant with respect to monographs, and the nascent digital system has not yet coalesced around a multitude of emerging digital affordances.