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.

Probability Distributions for Noise Plus Several Sine Waves--The Problem of Computation

Abstract: The problem of computing the distributions of the envelope and instantaneous value of the sum of several sine waves plus Gaussian noise is reviewed. It is pointed out that the associated integrals can be efficiently evaluated by the trapezoidal rule except when the noise is small. Approximations which hold when the noise is small are given.

Analog quadrature modulator (AQM) error compensating apparatus and method

Abstract: An AQM error compensating apparatus includes: a predistorter for distorting a signal so as to have the opposite characteristics of nonlinear distortion characteristics of a digital input signal; an error compensating unit for compensating I/Q digital signals outputted from the predistorter according to an error correction signal; a digital/analog converter for converting the I/Q digital signals of the error compensating unit into I/Q analog signals; a modulator for frequency-modulating the I/Q analog signals outputted from the digital/analog converter; a power amplifier for amplifying the output signal of the modulator to a directional coupler; a down-converter for down-converting a feedback signal inputted from the directional coupler; an analog/digital converter for converting the output signal of the down-converter into a digital signal; and a controller for comparing the output signal of the analog/digital converter with the I/Q digital signals inputted from the predistorter, and applying an extracted error correction signal into the error compensating unit. An AQM error can be compensated by extracting the DC offset and gain and the correction value for the phase error by using a sine wave for an initial certain time of a system, and even while a signal is being transmitted after being varied, the AQM error also can be compensated by comparing an inputted reference signal and a feedback signal and extracting a correction value for each error. Thus, the error can be accurately compensated according to its occurrence.

Control method for semi-active damper

Abstract: A semi-active control method for a controllable fluid damper (22) used in seat support (11). The present method filters a relative displacement signal (44) phase shifting the relative displacement sine wave by an angle from greater than 0° through an angle less than 90° to get a relative rate. The sign of the relative rate is compared to that of an absolute velocity curve obtained by integrating the absolute acceleration value obtained by an accelerometer (40) attached to the controlled seat (11). If the signs are the same, the output to the damper (22) is set to a minimum; if the signs are different, the value is set at the absolute velocity multiplied by an input gain. Endstop limits can be implemented with this control method.

Electrical Excitation of Nerves in the Skin at Audiofrequencies

Abstract: This is a report of results obtained in preliminary tests of perception of signals applied directly to the skin in the form of electrical potentials. The lowest signal level that could be felt and the highest level that could be applied without extreme discomfort to the observers were determined for sine wave potentials ranging from 100 to 10,000 cps. The difference between the lowest and highest levels was about 25 db over this frequency range.Difference limen measurements for intensity and frequency showed that intensity discrimination is not greatly different from what it is for hearing, but the ear is vastly superior in the matter of frequency discrimination.