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Phase (waves)

About: Phase (waves) is a research topic. Over the lifetime, 48256 publications have been published within this topic receiving 526394 citations.


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Patent
17 Jul 2008
Abstract: PROBLEM TO BE SOLVED: To provide a phase difference detection device for properly deciding reliability of the result of detecting a phase difference even for a pair of image signals out of phase without requiring imaging with uniform light, and to provide an imaging apparatus, a signal level correction method, and a signal level correction program for a phase difference detection device. SOLUTION: The ratio between an image A and an image B is obtained as the comparison result of the images A and B obtained from a pair of optical images. The variance is then calculated in order to evaluate the statistical fluctuation of the ratio obtained for each pixel. The fluctuation due to the variance is evaluated for each phase difference while the phase between the image A and the image B is shifted. An output difference between the images A and B is corrected on the basis of the evaluation result of the fluctuation. COPYRIGHT: (C)2010,JPO&INPIT

12 citations

Journal ArticleDOI
TL;DR: In this paper, the phase variance, mutual coherence function, and phase-difference temporal power spectrum of an optical wave propagating through rainfall were analyzed, including the effects of a distribution of rain droplet sizes and their associated terminal velocities.
Abstract: We apply Tatarski’s spectral expansion technique of optical fields to calculate the phase variance, mutual coherence function, and phase-difference temporal power spectrum of an optical wave propagating through rainfall. The analysis includes the effects of a distribution of rain droplet sizes and their associated terminal velocities. The general features of the associated phase statistics are discussed, and numerical results are presented as a function of the rainfall rate. It is shown that for up to moderate rainfall conditions (i.e., ≲4 mm/h) the lateral phase coherence of the wave is not significantly degraded for a propagation path of the order of a kilometer. It follows that under these conditions (moderate and less) rainfall will not pose serious limitations to coherent optical systems such as laser radars. In particular, in contrast to clean-air turbulence, rain-induced phase degradations will not limit the aperature size of coherent optical systems in many practical situations. In addition, the theory presented here predicts that for low-cross-wind speed conditions the high-frequency portion of the temporal-phase-difference power spectrum varies as f−7, where f is the frequency. This behavior has been seen experimentally.

12 citations

Patent
16 Feb 2011
TL;DR: In this paper, a method for detecting the phase sequence of three-phase power supply of a motor is presented. But the method is not suitable for the detection of the phase of a single motor.
Abstract: The invention discloses a method for detecting the phase sequence of three-phase power supply. The method comprises the following steps of: converting a three-phase alternating current accessed into a motor into a low-voltage square signal; starting to detect the signal when a start button switch of the motor is started; triggering a timer when a first rising edge of a phase A is detected; taking a time interval of the rising edge of each phase A as a signal period; detecting the rising edges of a phase B and a phase C in the signal period; recording the time of the timer when the rising edges of the phase B and the phase C are detected; and comparing time sequences of the current phase A, the current phase B and the current phase C according to the time of the rising edges of the phase B and the phase C, wherein if the time sequences of the current phase A, the current phase B and the current phase C are in a positive sequence, the motor is started, otherwise, the motor cannot be started. The invention provides a conversion circuit for converting the three-phase alternating current into the low-voltage square signal, and the method, a system and a product for detecting the phase sequence of the three-phase power supply of the motor in a motor drag pump.

12 citations

Journal ArticleDOI
TL;DR: In this article, the analysis and design of printed phase shifters based on the microstrip line are described and a spectral domain analysis is presented where the necessary Green's functions are formulated using the transmission matrix technique.
Abstract: The analysis and design of printed phase shifters based on the microstrip line are described. A spectral-domain analysis is presented where the necessary Green's functions are formulated using the transmission matrix technique. The nonreciprocal characteristics for single-layer and multilayer structures are studied. Microstrip-slot in a multilayer structure of ferrite and high-dielectric material is found to have considerably more nonreciprocity than microstrip-slot for microstrip in a single-layer structure. Over 65 degrees /cm is predicted for certain optimized designs. This, in addition to the 50- Omega design capability of the line, makes the microstrip-slot line a suitable choice for phase shifting applications. A multilayer microstrip-slot line was constructed on a rectangular ferrite toroid. Differential phase shifts of roughly 45 degrees /cm were measured over a 6.0-8.5-GHz frequency range. These results are in good agreement with the analysis. >

12 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202237
20211,357
20201,826
20192,039
20181,864
20171,712