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To meet the requirement of doing periodic inter-laboratory verification and self assessment, a device so called reference source is crucial. In this paper, an existing conducted emission reference source is reviewed and a new design is proposed. The considerations are explained, preliminary results are presented thereupon, and the benefits of the design are emphasized in the conclusion.
Total voltage sources and Thevenin equivalent circuits are derived by measurements and simulations using IBIS models to characterize the conducted emissions from ICs. The constructed noise source model for a test IC is applied in systemlevel simulations and the calculated far field radiation is validated with measurements. The agreement between simulated and measured results demonstrates the effectiveness...
This paper describes the algorithm for estimating frequency, amplitude and phase of fundamental component in harmonically distorted waveform. The algorithm minimizes phase difference between sine model and sampled waveform by effectively canceling out the influence of harmonic components. It uses three parameter sine fit algorithm for all phase calculations. The resulting estimates show up to two...
This paper describes an automated non-coherent sampling THD meter based on the 24 bit digitizer National Instruments PXI 5922. The THD meter is designed for a frequency range up to 1 MHz with analysis of the harmonics up to 6 MHz. Contrary to commercial devices developed THD meter displays a signal spectrum and gives user the possibility to evaluate impurities in the signal affecting THD calibration...
Effects of transmit jitter on lossy clock channel are analyzed analytically by treating the 1010 input clock signal as a sinusoidal wave with a phase modulation that represents jitter. Jitter-to-amplitude-modulation transfer functions are derived for sinusoidal jitter and random jitter in terms of the signal transfer function or S-parameters. Input jitter is shown to induce amplitude modulation in...
The harmonic pollution has become a more and more serious problem because of the large-scale application of nonlinear electrical loads in power systems. It is known to all that fast Fourier transformation (FFT) is an effective method for power signal harmonic analysis, but aliasing effect, picket fence effect, spectrum leakage and spectrum disturbance make it suffer from inevitable limitation. In...
In this paper, the hyperbolic S-transform (HS-transform) has been generalized with the introduction of the whole time frequency regulation factor and the regulation of frequency in the HS window function. Combined with the idea of incomplete S-transform, a rapid harmonic detection based on generalized HS-transform (GHST) is proposed. Firstly, it detected each harmonic frequency according to the dynamic...
The nature of digital hydraulic systems may cause severe fluid-borne noise problems because of the pulsed nature of the flow. An effective method to reduce the noise that does not impair the system performance and efficiency is needed. This article reports on initial investigations of an active valve for pressure pulsation attenuation in switched inertance hydraulic systems (SIHS) based on in-series...
This paper proposes a spatial filter based on the cross-spectral density between directional microphones. The operation principle of the proposed spatial filter is predicated on the principles of the cross pattern coherence, which is a parametric spatial filtering technique that uses coherence-based measures as a criterion for focusing on specific directions. In this work, the choice of the directional...
Due to the proliferation of distributed power systems, renewable energy sources and systems working in islanding mode, the issue of grid frequency variations has come to be an important topic. In this paper, two single-phase and one three-phase phase-locked loop methods are studied. The resulting PLLs algorithms are completely developed in the discrete plane in order to be directly applied on digitals...
In this work there were reviewed the issues of robustness of frequency estimation of harmonic signal mixed with additive Gaussian noise and chaotic impulse interference by the method of maximum likelihood. There were analyzed estimates obtained by both taking into account and excluding the likelihood function of interference parameters. It was investigated the influence of a priori information about...
In this paper we consider the zero-forcing (ZF) and minimum mean square error (MMSE) criteria for signal recovery using linear operators as equalizers for signals observed on the 2-sphere that are subject to linear distortions and noise. The distortions considered are bounded operators and can include convolutions, rotations, spatial and spectral truncations, projections or combinations of these....
Many algorithms have been proposed for harmonic estimation to improve the power quality performance, but till today it is still a challenge for accurate estimation. In this paper an adaptive filtering algorithm called Fast Transverse Recursive Least Square (FT-RLS) is applied for the first time for estimating harmonic parameters. The algorithm has been considered to estimate the amplitudes, phases...
Spherical eigenbeamforming microphone arrays have become a subject of interest in recent years [1-6]. General beampattern design and implementation are simplified due to the decomposition of the soundfield into orthonormal spherical harmonic (SH) “building block” eigenbeams. Eigenbeams are then combined to realize the beamformer. In this paper we present a remarkably straightforward and computationally...
In this paper, a robust voice activity detection (VAD) for arbitrary noise environment is proposed. The conventional VAD has a limitation that the VAD is performed well in a particular environment. To cope with the limitation, speech and noise classes are divided into several clusters using unsupervised clustering, By discriminative weight training, optimal weights of each cluster are obtained and...
This paper proposes a direct approach based on Principal Curves for power quality disturbance detection. The main advantages of the method lie in its low computational burden in the operational phase, its capability to detect disturbances when power frequency is time-varying and its good performance to signals exhibiting high noise levels. Simulation and experimental results show that the proposed...
This paper presents a detail analysis on the design and integration of interphase inductor for interleaved three phase voltage-source-inverters (VSI). The benefits of interleaving on EMI filter weight reduction are presented. Interleaving can cancel certain order of harmonics in the total output current and reduce the size and weight of the EMI filter to meet certain EMI standard. However, it also...
In this paper a flat supply voltage is produced for low-noise and low-jitter applications. A high gain two-stage amplifier, utilizing the indirect frequency compensation technique, is used to enhance the resolution of BGR loop. Then, the temperature-compensated BGR is used within the LDO loop to adjust the supply voltage around the desired value. A new start-up circuit is proposed to simply provide...
Jitter is a crucial factor in high speed and high performance ADC testing. This paper proposes an efficient and accurate jitter estimation method based on one frequency measurement. Applying simple mathematical processing to the ADC output in time domain, the RMS of jitter and noise power are obtained. Furthermore, prior information of harmonics does not need to know before the processing. The algorithm...
Most of speech enhancement systems suffer from musical residual noise which can be efficiently removed by a post processor. However, post-processing on enhanced speech will impact a speech signal, causing a quantity of speech distortion. Speech quality is deteriorated. In this study, we proposed using harmonic compensation to improve speech quality for a vowel. Initially, a speech enhancement algorithm...
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