Time-domain Data Processing Research Articles

Multivariate modelling of the microstructural quality of food emulsions based on NMR

Understanding the relations between sensory/physical parameters and the underlying microstructural features is an essential step for designing and manufacturing novel food products. ‘Deductive’ strategies to derive such structure–property relationships operate on time-scales, which do not match with the currently required pace of research and development. In this work an ‘inductive’ approach has been outlined that deploys benchtop spectroscopic NMR and NIR measurements and multi-variate data analysis in order to generate explorative models that relate microstructure and functional parameters. Using protein-stabilised oil-in-water model emulsions, the use of a partial least squares and a multi-linear regression approach for processing and analysis of time-domain NMR data is demonstrated, and benchmarked against the deployment of NIR spectroscopy.

Data correction of the force balanced accelerometer

Successive formula method for data correction of force balanced accelerometer proposed in this paper is obviously effective for time domain data processing. The method has such characteristics that computing precision is high and is not artificial ascertain filter frequency window. Using successive formula can give a parameter identifying method of the damping ratio and the natural angular frequency for force balanced accelerometer. On this problem, we will research in another paper.

Time-domain wave-oriented data processing of scattering by nonuniform truncated gratings

In a companion paper [ J. Opt. Soc. Am. A11, 2675 ( 1994)] we investigated wave-oriented processing techniques that extract from frequency-domain (FD) scattering data for nonuniform truncated thin-wire or strip gratings the wave phenomenology that ties features in data to scattering mechanisms that are responsible for these features. The resulting observable-based parameterization (OBP) should be useful for construction of wave-based algorithms aimed, through forward and backward propagation routines, at design, classification, and imaging. The processing strategy projects the data, which are assembled on an elevated track at height z parallel to the grating-plane coordinate x, onto the (x, kx) phase-space subdomain by means of windowed Fourier transforms; here kx is the spatial spectral wave number corresponding to x. The (x, kx) phase-space distributions and their information content for various grating configurations are analyzed in detail and are related to previously derived analytic scattering models based on truncated local Floquet modes (FM’s) and on FM-modulated edge diffractions. We explore time-domain (TD) wave-oriented processing techniques for scattering by truncated gratings produced by a pulsed incident plane wave. By spatial–temporal resolution, the TD data base adds to the FD processing options. Time (t)–frequency (ω) phase-space distributions implemented through windowed transforms extract from TD data new TD phenomenology, TD-OBP, that differs fundamentally from that in the frequency domain: strongly dispersive TD-FM’s with prolonged time-varying frequency response ωm(t), where m is the FM index, and temporally well-resolved weakly dispersive impulselike edge diffractions. These phenomenologies extracted from the TD scattering data are interpreted in terms of, and shown to be in agreement with, previously developed analytic TD scattering models. The (t, ω) processing is applied to pulsed plane-wave scattering data produced for various grating configurations by previously calibrated numerical reference codes and reveals the changes in (t, ω) footprints that are attributable to departures from strict canonical truncated periodicity. Short-pulse TD excitation is found to resolve the element structure within each scattering cell directly, in contrast to (t, ω) processing, in which element-structure information is tied indirectly to the FM excitation strengths.

Dispersive modes in the time domain: analysis and time-frequency representation

Four algorithms for time-frequency (TF) distributions are considered for the processing and interpretation of dispersive time-domain (TD) data: the short-time Fourier transform, frequency and time-domain wavelets, and a new ARMA-based representation. The TF resolutions of the various distributions are discussed and compared with reference to results for the scattered fields from a chirped finite grating excited by a pulsed plane wave. The processing in the TF phase space extracts TD phenomenology, in particular the instantaneous dispersion relation /spl minus/ with its associated time-dependent frequencies-descriptive of the local TD Floquet modes on the chirped truncated grating.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Time-domain optical data storage by photon echo

Principles and applications of time-domain optical data storage using stimulated photon echo are briefly reviewed. Special emphasis is laid upon the comparison of this memory with holography; both memories use the interference between two optical waves. Some new experimental developments are introduced using samples of europium-ion-doped crystals, one of the most promising candidates in time-domain data storage. Some other topics, such as ultrafast data storage, time-domain data processing, and time- and spatial-image storage using photon echo, are also discussed.