Time of flight cameras may emerge as the 3-D sensor of choice. Today, time of flight sensors use phase-based sampling, where the phase delay between emitted and received, high-frequency signals encodes distance. In this paper, we present a new time of flight architecture that relies only on frequency—we refer to this technique as frequencydomain time of flight (FD-TOF). Inspired by optical cohe...

Abnormal velocities in passive structures such as one-dimensional (1-D) photonic crystals and a slab having a negative index of refraction are discussed. In the case of 1-D photonic crystal, the frequencyand time-domain experiments for waves tuned to the bandgap of the photonic crystal demonstrate a positive group velocity exceeding the speed of light in vacuum (superluminal). In the case of a ...

The purpose of this study was to extract motion characteristics closely related to high evaluation by judges, through a comparison of “side-step” movement between eight expert and eight non-expert dancers. Their step motions were captured and the head trajectory relative to the centre of mass, face inclination, and time lags among neck, trunk, hip and knee angles were calculated. As a result, a...

A triplexer for ultra-wideband radio implemented entirely with distributed microstrips is presented. The triplexer is composed of a triplex junction network and three bandpass filters. The circuit is integrated in a flex-rigid printed circuit board. Three flat 1 GHz sub-bands in the frequency band 6-9 GHz have been achieved. The group delay variation within each 1 GHz sub-band was measured to b...

We present the design, fabrication and testing of the piece-wise stepped-chirp fiber Bragg gratings (FBGs) with arbitrary group delay responses using a uniform phase mask under pre-stretched condition. The method involves writing a series of sub-gratings on a prestretched fiber whose length is varied during the UV exposure process. Two motorized stages are employed to control the length of the ...

Current speech recognition systems use mainly amplitude spectrum-based features such as MFFC for acoustic feature parameters, while discarding phase spectral information. The results of perceptual experiments, however, suggested that phase spectral information based on long-term analysis includes certain linguistic information. In this paper, we propose the use of phase features based on long-t...

In this paper, the radiation pattern of two experimental models of circular waveguide antenna arrays on spherical surface is obtained experimentally and compared with theoretical patterns. We have omitted the phase delay of feed system signals because we have only compared measured and theoretical results in order to verify theoretical results, without trying to improve the best radiation chara...

Cavitation instabilities in turbo-machinery such as cavitation surge and rotating cavitation are usually explained by the quasi-steady characteristics of cavitation, mass flow gain factor and cavitation compliance. However, there are certain cases when it is required to take account of unsteady characteristics. As an example of such cases, cavitation surge in industrial centrifugal pump caused ...

Aims. The effect of frequency-dependent AGN core positions (“core-shifts”) on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods. The basic equations relating to VLBI astrometry are reviewed, including the effects of source structure. A power-law representation of core-shifts, based on both observations and theoretical considerations of jet co...

On 18 November 1993, we observed the QSO 1150+812 and the BL Lac object 1803+784, nearly 15 apart on the sky, with a VLBI array, simultaneously recording at 8.4 and 2.3 GHz. Using difference astrometry techniques, we determined the coordinates of 1803+784 relative to those of 1150+812 to be ∆α = 6 7 33. 18469± 0. 00020 ∆δ = −2 30′ 25. 13557± 0. 00075 These standard errors contain estimated cont...