1,738 research outputs found
Efficient Sum-of-Sinusoids based Spatial Consistency for the 3GPP New-Radio Channel Model
Spatial consistency was proposed in the 3GPP TR 38.901 channel model to
ensure that closely spaced mobile terminals have similar channels. Future
extensions of this model might incorporate mobility at both ends of the link.
This requires that all random variables in the model must be correlated in 3
(single-mobility) and up to 6 spatial dimensions (dual-mobility). Existing
filtering methods cannot be used due to the large requirements of memory and
computing time. The sum-of-sinusoids model promises to be an efficient
solution. To use it in the 3GPP channel model, we extended the existing model
to a higher number of spatial dimensions and propose a new method to calculate
the sinusoid coefficients in order to control the shape of the autocorrelation
function. The proposed method shows good results for 2, 3, and 6 dimensions and
achieves a four times better approximation accuracy compared to the existing
model. This provides a very efficient implementation of the 3GPP proposal and
enables the simulation of many communication scenarios that were thought to be
impossible to realize with geometry-based stochastic channel models
Evaluation of output frequency responses of nonlinear systems under multiple inputs
In this paper, a new method for evaluating output frequency responses of nonlinear systems under multiple inputs, defined as a sum of sinusoids of different frequencies, is developed. The method circumvents difficulties associated with the existing âfrequency-mix vectorâ based approaches and can easily be applied to investigate nonlinear behaviors of practical systems, including electronic circuits, at the system simulation and design stages. Application of the method to the analysis of nonlinear interference and distortion effects in communication receivers is studied, and specific procedures are proposed which can be directly used in practice for this analysi
Final Proposal for Digital Audio Systems, DESC9115, 2018
Time Warp is a fantastic plugin that converts your digital audio workstation (DAW) to a powerful time stretcher system. The function offers a reliable algorithm based on Filter Bank (sum of sinusoids in frequency domain), the technique that can implement high-fidelity time scaling on a variety of sound sources such as synchronizing the audio with video content and tempo adjustment of the music
Novel Sum-of-Sinusoids Simulation Models for Rayleigh and Rician Fading Channels
The statistical properties of Clarke\u27s fading model with a finite number of sinusoids are analyzed, and an improved reference model is proposed for the simulation of Rayleigh fading channels. A novel statistical simulation model for Rician fading channels is examined. The new Rician fading simulation model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to existing Rician fading simulators that utilize a non-zero deterministic specular component. The statistical properties of the proposed Rician fading simulation model are analyzed in detail. It is shown that the probability density function of the Rician fading phase is not only independent of time but also uniformly distributed over [-pi, pi). This property is different from that of existing Rician fading simulators. The statistical properties of the new simulators are confirmed by extensive simulation results, showing good agreement with theoretical analysis in all cases. An explicit formula for the level-crossing rate is derived for general Rician fading when the specular component has non-zero Doppler frequenc
A sum-of-sinusoids based simulation model for the joint shadowing process in urban peer-to-peer radio channels
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Minimax Current Density Coil Design
'Coil design' is an inverse problem in which arrangements of wire are
designed to generate a prescribed magnetic field when energized with electric
current. The design of gradient and shim coils for magnetic resonance imaging
(MRI) are important examples of coil design. The magnetic fields that these
coils generate are usually required to be both strong and accurate. Other
electromagnetic properties of the coils, such as inductance, may be considered
in the design process, which becomes an optimization problem. The maximum
current density is additionally optimized in this work and the resultant coils
are investigated for performance and practicality. Coils with minimax current
density were found to exhibit maximally spread wires and may help disperse
localized regions of Joule heating. They also produce the highest possible
magnetic field strength per unit current for any given surface and wire size.
Three different flavours of boundary element method that employ different basis
functions (triangular elements with uniform current, cylindrical elements with
sinusoidal current and conic section elements with sinusoidal-uniform current)
were used with this approach to illustrate its generality.Comment: 24 pages, 6 figures, 2 tables. To appear in Journal of Physics D:
Applied Physic
Effective extraction and filtering of frequency components in physiological signals using sum-of-sinusoids modelling
In biological signal processing, modelling and extraction of specific frequency components constitute an important procedure for filtering signal components of interest as well as artefact removal. Under some interference scenarios, a satisfactory elimination of artefacts from the signal must be even performed by subtraction of an artefact waveform model or template, rather than the use of linear band-pass filters. That is the case of the gradient artefact induced in the EEG within the fMRI scanner, which cannot be characterized by a specific bandwidth or spectral content. This paper presents a simple and accurate approach based upon sum-of-sinusoids modelling for signal and artefact frequency components representation in physiological signals. According to the proposed method, each signal frequency component is approximated as a sinusoid, whose amplitude and phase parameters are estimated by making use of the Discrete Fourier Transform (DFT). The proposed approach reveals to perform an effective modelling and extraction of ECG signal components as well as underlying gradient artefacts in the EEG signal
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