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.

Sine-Wave Amplitude Coding at Low Data Rates

Abstract: An analysis/synthesis system based on the sinusoidal speech model has been developed [1] In that system, the sine-wave amplitudes and frequencies are located by searching for the peaks of the magnitude of the short-time Fourier transform (STFT) of the input speech The phases are computed from the real and imaginary parts of the STFT at the measured frequencies The frequencies on successive frames are matched, used in a cubic phase interpolator and applied to a sine-wave generator Each sine wave is amplitude-modulated by the linear interpolation of the matched sine-wave amplitudes At a 10 ms frame rate, this system produces speech that is perceptually indistinguishable from the original [1] Since it is not possible to code all of the sine-wave parameters at low data rates, a system has been developed that codes the sine-wave frequencies by fitting a harmonic set of sine waves to the input waveform using a modified mean-squared error criterion [2], and codes the phase information implicitly using a voicing adaptive transition frequency to provide for a mixed voiced/unvoiced phase excitation model [3] Provided a postfilter is used at the synthesizer to attenuate the noise in the formant nulls, the speech synthesized by this system is of quite high quality having achieved a DAM score of 630 in the uncoded mode Since the fundamental frequency can be coded using ≈ 7 bits and the voicing measure can be coded using ≈ 3 bits, then the possibility exists for good speech quality at low data rates provided the sine-wave amplitudes can be coded efficiently In this paper the zero-phase, harmonic analysis/synthesis system and the post-filter design methodology will be described and then the various techniques that have been examined for coding the sine-wave amplitudes will be discussed

Wide-Range Filter-Based Sinusoidal Wave Synthesizer for Electrochemical Impedance Spectroscopy Measurements

Abstract: A filter-based wide-range programmable sinusoidal wave synthesizer for electrochemical impedance spectroscopy measurement is proposed. The adopted filter is implemented with switched-capacitor circuits, so its corner frequency is accurate and adjustable by changing its switching frequency. The proposed sine wave synthesizer is implemented by using a 0.35 $\,\mu{\rm m}$ 2P4M 3.3 V mixed-signal polycide process. According to the measured results, the output frequency of the proposed synthesizer is 40 mHz–40 kHz . The measured total harmonic distortion is 0.073% at 10 Hz and 0.075% at 10 kHz, both of which are better than that of a typical function generator.

Dispersive Pulse Propagation Parallel to the Interfaces of a Laminated Composite

Abstract: This paper presents a theoretical analysis of the geometric dispersion of transient stress waves in a linearly elastic laminated composite. The loading is a uniform pressure of step-function time-dependence, applied to a half space. The laminates are perpendicular to the half-space boundary. The mathematical treatment is borrowed from the theory of wave propagation in rods. Fourier transforms are applied to time and the coordinate in the propagation direction. Inversion of the spatial transform by residues yields a formal solution in the form of an infinite series of integrals. Each of these integrals is the contribution to the transient response from a mode of sinusoidal wave propagation. Application of the saddle-point technique for long-time asymptotic approximation indicates that the low-frequency portion of the integral from the first mode gives the dominant contribution, called the head-of-the-pulse approximation. The form of the expression for the head-of-the-pulse approximation leads to the definition of a characteristic dispersion time τ. Since τ is a single quantity which describes the dispersion of the wave, it simplifies parametric studies. A closed-form algebraic expression for τ is presented, which has a simple dependence on the propagation distance and spacing of the laminates. Numerical examples for boron-epoxy and glass-epoxy laminates are given.

Sinusoidal Voltammetry for the Analysis of Carbohydrates at Copper Electrodes

Abstract: A digital approach for the collection and analysis of electrochemical frequency domain spectra is presented for the oxidation of carbohydrates at a copper electrode using a continuous, large-amplitude sine wave as an excitation waveform. The background charging current response is a phase-shifted sine wave with the major frequency component concentrated at the fundamental frequency. A nonlinear faradaic response due to the oxidation of sugars produces significant signal intensities at the higher harmonics as well as the fundamental frequency. Examination of the frequency spectra of glucose and maltose leads to selective and sensitive detection of these sugars at a copper electrode. The selectivity of this measurement relies on the inherent difference in the frequency domain spectra (i.e., magnitude and phase of each harmonic) of sugars of different sizes. This frequency distribution is dramatically affected by temperature, indicating the effect of kinetics in the mechanism for the oxidation of sugars. The...