On the use of a digital computer as a two-phase variable-amplitudevariable-frequency oscillator

A feasibility study on the use of a digital computer as a variable-amplitude variable-frequency oscillator which generates two-phase sinusoidal excitation control signals for a dual-excited synchronous generator is described. The oscillator uses two input signals. One input signal is used to control the frequency of the oscillator outputs, and the other is used to control their amplitudes. By a single variable, the software can be configured to vary the oscillator frequency range and to greatly reduce (almost eliminate) the harmonic distortion of the output signals. The harmonic distortion is constant and independent of the output frequency for each possible oscillator frequency range. The software-based oscillator design is flexible and can be used to generate different types of multiphase signal waveforms     

A VLSI analog computer/digital computer accelerator

The design of a single-chip VLSI analog computer fabricated in a 0.25-/spl mu/m CMOS process is described. It contains 80 integrators, 336 other linear and nonlinear analog functional blocks, switches for their interconnection, and circuitry to enable the system's programing and control. The IC is controlled, programmed and measured by a PC via a data acquisition card. This arrangement has been used to simulate ordinary differential equations (ODEs), partial differential equations, and stochastic differential equations with moderate accuracy, significantly faster than a modern workstation. Techniques for using the digital computer to refine the solution from the analog computer are presented. Solutions from the analog computer have been used to accelerate a digital computer's solution of the periodic steady state of an ODE by more than 10/spl times/. The IC occupies 1 cm/sup 2/ and consumes 300 mW. An analysis has been done showing that the analog computer dissipates 0.02% to 1% of the energy of a general purpose digital microprocessor and about 2% to 20% of the energy of a digital signal processor, when solving the same differential equation.     

Implementation of linear programming with a digital stochastic computer

The problem of online computation of linear-programming problems with digital-stochastic-computing structures is considered. Such techniques are shown to provide very economical and fast online computations. The simple logic-circuits used for the realisation of the stochastic operators are ideally suited for large-scale integrated-circuit fabrication. Experimental results are presented for the stochastic computation of linear programming with an algorithm based on steepest-descent techniques.     

Network analysis by digital computer

This article gives a brief survey of various methods for network analysis by digital computer. Topics discussed include methods and programs for ladder networks, mesh and nodal analysis, network topology, electronic circuit analysis, state-variable analysis, n-port hybrid matrix analysis, and nonlinear circuit analysis. Also given is a brief discussion concerning algorithms for inverse Laplace transformation, and methods for obtaining magnitude, phase and delay responses in the frequency domain.     

Electronic-network analysis by digital computer

The development of a program based on 2 × 2 matrices for computing the linear steady-state performance of networks against chosen frequencies of a sinusoidal input signal is described. Limitations and projected extensions of the program are briefly discussed.     

计算机教学中学生创造性思维能力的培养

我国目前计算机课程还是按照传统的课本教学,使得计算机课程教学质量无法提升。计算机教师应该顺应时代的发展,使用创新的教学模式,让学生能够主动融入计算机课堂中来,提升自己的思维创造能力。     

Simulation of dynamic physical systems using a digital process-control computer

A digital computer designed for process control can be used for the simulation of complex continuous systems. The program is to contain facilities for the inclusion of items of operating equipment within the simulation study.     

中小型计算机监测系统研究

介绍了计算机监测系统中应用到的一些先进技术．PLC技术、集散控制系统（DCS）、现场总线技术等．并结合各种技术的应用现状对比较分析了它们的优缺点．分析了监测系统的一般设计原则。在此基础上．提出了一种适合中小型监测系统的集散式计算机监测系统架构。     

中小型计算机监测系统研究

介绍了计算机监测系统中应用到的一些先进技术,PLC技术、集散控制系统(DCS),现场总线技术等,并结合各种技术的应用现状对比较分析了它们的优缺点,分析了监测系统的一般设计原则.在此基础上,提出了一种适合中小型监测系统的集散式计算机监测系统架构.     

Symbolic solution of networks by digital computer

The letter briefly discusses the problem of finding the symbolic expression of a network function (in particular, a driving-point or a transfer impedance). After dividing the problem into two subsequent steps, some methods for the solution of the first step, already presented in the technical literature, are discussed. A method for the solution of the second step is then proposed.     

A survey of digital computer memory systems

Many types of storage and memory systems have been proposed for use in digital computing systems. This survey paper discusses only the various systems whose reaction time is faster than human reaction time, employing a historical approach to the subject. Criteria for evaluation are discussed, and comparisons given among the different systems as to general applicability, ease of construction and use, speed of operation, latency time, memory span, and economy     

The insulated conductor as a scattering antenna in a relatively dense medium

A simple formula is derived for the current induced in an insulated conducting cylinder when embedded in an isotropic homogeneous dissipative medium and excited by a periodic electric field with uniform amplitude and phase along its axis. The currents on electrically short, resonant, and terminated insulated conductors are discussed.     

The power spectrum of digital FM as produced by digital circuits

A simple exact method is given for calculating the power spectrum of a frequency modulated filtered M-ary data signal. The power spectrum and its discrete components are given in closed form for any pulse shape. The pulses are those generated by a digital transversal filter and the FM modulator is that composed of an ideal digital integrator followed by a phase modulator (look-up table).     

高清晰度数字电视(HDTV)与个人电脑技术的融合

论述了个人电脑系统及计算机网络在HDTV技术发展中的地位和作用，从设计水平上分析了个人电脑处理播放HDTV节目的技术基础，提出了未来数字电视网络与计算机网络融合为一、个人电脑与电视合二为一的观点。     

Optimisation technique in delay-equaliser design by digital computer

This letter presents the necessary modifications in a method of synthesis of phase equalisers, which has been described in a companion paper, in order to make it suitable for automatic computation of phase equalisers of minimum complexity that will correct the assigned delay characteristic to within a prescribed error. The flow diagram for the program organisation is also given.     

A computer modeling approach for LSI digital structures

The paper presents a novel modeling approach to LSI MOST circuits performed at the gate level. A macromodel is analytically derived and provides a direct relationship between the input function and output response of the gate. This approach or macromodeling has been implemented for over 10 000 devices in LSI with only 32K of computer core and very fast computing time. The method employed relates directly the performance parameters (e.g., turn-on voltage, rise, and fall times, etc.) to the device parameters. An insight into the propagation delay of LSI structures is gained by statistically studying the transient performance of the system using Monte-Carlo techniques. Experimental results give ample evidence of good agreement with the computed results, for which various values of x0, oxide thickness, are used.