Sine wave

About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.

A multiphase direct-digital-synthesis sinewave generator for high-accuracy impedance comparison

Abstract: In this paper we report on the realization and characterization of a multiphase sinewave generator based on the direct-digital-synthesis technique using the latest Analog Devices direct-digital-synthesizer model AD9853. The generator is intended for use in high-accuracy impedance intercomparison setups; thus, particular attention is paid to the stability and distortion of the sine wave output signal. The sinewave frequency can be tuned in the range from 16 Hz to 16 kHz with a resolution <10 /spl mu/Hz and with a relative frequency short-term stability of 10/sup -7/, whereas the sinewave long-term amplitude stability is better than 10/sup -6/ at full amplitude output. Signal amplitude, frequency, and phase are monitored and set by means of a personal computer.

The velocity of a wave along a dislocation

Abstract: The behaviour of a small-amplitude infinite standing or travelling sine wave on a dislocation is examined. For a certain range of frequencies and wavelengths no elastic energy is radiated, but in general a suitable applied stress is required to maintain the motion. When, however, a certain relation between frequency and wavelength is satisfied no applied forces are necessary and the motion is self-maintaining. This relation may be expressed analytically in the limit of very long wavelengths, but in general it must be evaluated numerically. Curves are given for edge, screw and 60° dislocations in materials with various Poisson ratios. In the course of the calculation a value for the line tension of a sinusoidally deformed stationary dislocation is also obtained.

Position indicating apparatus for use in a digitizing tablet system

Abstract: A position indicating implement is disclosed having a first coil connected to a current source and a second coil inductively coupled with the first coil. A capacitor is connected in series with the second coil so that the current in the first coil induces a phase shifted current in the second coil. A tip extends from the barrel of the position indicating implement of the present invention. The tip is designed for placement on and movement over a digitizing tablet. A switch has been located near the tip so that it is easily accessible to a user's finger while holding the implement. The power source providing an alternating current to the first coil includes a digital switching circuit for producing a step function which approximates a sine wave and lacks any components at the second, third, fourth, fifth and sixth harmonics. The step function is filtered to produce a sine wave for delivery to the first coil. The switch near the tip of the implement may be used as a mouse switch so that the position indicating implement may be used as a mouse to indicate relative position rather than absolute position. Remote signaling may be accomplished by providing a switch in the circuit of the second coil. Calibration of the phase shift between the fields of the two coils may be accomplished by providing a line from the circuit of the second coil.

Static inverter wherein a plurality of square waves are so summed as to produce a sinusoidal output wave

Abstract: This invention relates generally to power inverting devices and more particularly, to static inverting devices which produce an output wave shape which closely approximates a sine wave.

A Simple Fourier Analysis Technique for Measuring the Dynamic Response of Manual Control Systems

Abstract: From a practical standpoint most dynamic response analysis techniques are complicated, expensive, and time consuming to mechanize and operate. These techniques usually require digital or special-purpose analog equipment, and the computations are often performed sometime after data are collected. Adaptive paramater tracking techniques partially overcome these faults: but they either have prescribed forms, which is an undesirable restriction for basic research, or in the case of free-form methods the computational requirements become excessive. To overcome these drawbacks, an on-line Fourier analysis technique has been developed which deals only with the input and error signals in a manual feedback control system. Several sine waves are used for the input, and the on-line data measurement includes the error variance and a simple means for obtaining the sine and cosine transforms of the error signal at each of the input frequencies. From this relatively small amount of data, we show simple ways to compute the open- and closed-loop dynamic response at input frequencies and the relative amount of linearly correlated power in the error signal. This paper describes the rationale and theory for the technique and discusses two methods for mechanizing it; one involving standard analog computer components and one based on conventional electromechanical components. Finally, a typical application of this method is presented.