Measurement Method of Amplitude Ratios and Phase Differences Based on Power Detection Among Multiple Ports

2019 ◽  
Vol 68 (12) ◽  
pp. 4615-4617 ◽  
Author(s):  
Ui-Gyu Choi ◽  
Ho-Yeon Kim ◽  
Seong-Tae Han ◽  
Jong-Ryul Yang
Keyword(s):  
Measurement Method ◽  
Amplitude Ratios ◽  
Phase Differences

scholarly journals On the Application of Fourier Decomposition Parameters

1993 ◽  
Vol 134 ◽  
pp. 157-158
Author(s):  
J. O. Petersen
Keyword(s):  
Fourier Analysis ◽  
Light Curves ◽  
Amplitude Ratios ◽  
Fourier Decomposition ◽  
Practical Applications ◽  
Convincing Argument ◽  
Lee Form ◽  
Modern Form ◽  
Made In ◽  
Phase Differences

The application of Fourier decomposition parameters has revolutionized important areas of investigations of Cepheid type variables since the introduction of Fourier analysis in its modern form by Simon and Lee (1981).In the literature several different representations of the results of Fourier analysis have been utilized. In view of the growing interest for applications of Fourier decomposition it is important to use and publish Fourier data in an optimal way. Most studies until now have used amplitude ratios and phase differences derived from traditional light curves giving the light variation in magnitudes, following the original recipe of Simon and Lee (1981). However, Stellingwerf and Donohoe (1986) advocated the use of phases rather than phase differences. Recently, Buchler et al. (1990) argued that the standard Simon & Lee form contains all relevant physics, and suggested analysis of flux-values rather than of magnitudes, because this removes the distorting effects of constant, false light. Thus there are many choices to be made in practical applications of Fourier analysis, and there is at present no convincing argument for preferring one specific representation.

scholarly journals Multisite spectroscopic and photometric observations of the pulsating sdB star PG 1605+072

2004 ◽  
Vol 193 ◽  
pp. 230-233
Author(s):  
S.J. O’Toole ◽  
S. Falter ◽  
U. Heber ◽  
C.S. Jeffery ◽  
S. Dreizier ◽  
...  
Keyword(s):  
Amplitude Ratios ◽  
Data Set ◽  
Velocity Amplitude ◽  
Mode Identification ◽  
Horizontal Branch Stars ◽  
Massive Data Set ◽  
Photometric Observations ◽  
First Results ◽  
Formation And Evolution ◽  
Phase Differences

AbstractWe present the first results from the MultiSite Spectroscopic Telescope (MSST) observations of the sdBV star PG 1605+072. Pulsating sdB stars (V361 Hya stars) offer the chance to gain new insights into the formation and evolution of extreme Horizontal Branch stars using the tools of asteroseismology. PG 1605+072 is an outstanding object in its class, with the richest frequency spectrum, the longest periods, and the largest variations. The MSST campaign took place in 2002 May/June and we present here the massive data set, made up of 399 hr of photometry and 151 hr of spectroscopy. The overall aims of the project are to examine light/velocity amplitude ratios and phase differences, changes in equivalent width/line index, and λ-dependence of photometric amplitudes, and to use these properties for mode identification.

A Multi-Point Radio Displacement Measurement Method for Testing Quake-Proof Structure

2002 ◽  
Author(s):  
Atsushi Okamura ◽  
Tadashi Mikoshiba ◽  
Wataru Yosizaki ◽  
Hideki Nagai ◽  
Atsushi Mogi ◽  
...  
Keyword(s):  
Signal Processing ◽  
Measurement Method ◽  
Experimental System ◽  
Digital Signal ◽  
Reference Points ◽  
Displacement Measurement ◽  
Shaking Table ◽  
Processing Unit ◽  
Signal Processing Unit ◽  
Phase Differences

In this paper, we propose a remote 3-D displacement measurement method using the radio wave for indoor shaking table facilities. It also shows the effectiveness of the proposed method by some radio experiments using a shaking table. The proposed measurement system consists of simple transmitters attached to each reference point and several receiving antennas at different places connected with a digital signal processing unit. The locations of the transmitters are simultaneously estimated by observing the phase differences between signals at receiving antennas. This prototype radio experimental system consists of 3 transmitters of frequency 2.45GHz, 4 receiving antennas and a microcomputer. We made the demonstration for the reconstructions of the 0.1Hz and 2Hz sinusoidal excitations at 3 reference points of the testing structure on the shaking table. The accuracy of estimated displacement was several centi-meters to several mili-meters.

scholarly journals Non-adiabatic Asteroseismology of Near-Main Sequence Variable Stars

2004 ◽  
Vol 193 ◽  
pp. 458-461
Author(s):  
M.-A. Dupret
Keyword(s):  
Line Profile ◽  
Main Sequence ◽  
Variable Stars ◽  
Amplitude Ratios ◽  
Pulsating Stars ◽  
Excitation Mechanisms ◽  
Phase Differences

AbstractWe present in this talk a new linear non-adiabatic pulsation code: MAD. We detail all the possible applications of it in the frame of asteroseismology. By using it, photospheric observables such as multi-color photometric amplitude ratios, phase differences and line profile variations can be determined accurately and confronted with observations. Moreover, MAD enables the precisely analysis of the excitation mechanisms of pulsating stars. Applications to different kinds of variable stars (δ Sct, β Cephei, Slowly Pulsating B and γ Dor stars) are presented by Dupret et al. (these proceedings), Handler & Aerts (these proceedings), De Cat et al. (these proceedings) and De Ridder et al. (these proceedings).

scholarly journals Effect of convection modeling on the non-adiabatic seismic observables of δ Scuti stars

2006 ◽  
Vol 2 (S239) ◽  
pp. 385-387
Author(s):  
Josefina Montalbán ◽  
Marc-Antoine Dupret
Keyword(s):  
Phase Difference ◽  
Thermal Structure ◽  
Photometric System ◽  
Mixing Length ◽  
Amplitude Ratios ◽  
Stellar Models ◽  
Mixing Length Theory ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Phase Differences

AbstractPulsation frequencies in δ Scuti stars do not fall in the asymptotic domain, therefore, multi-band photometric methods are currently used to identify the pulsation modes. Theoretical photometric amplitude ratios and phase differences between photometric bands depend, however, on the treatment of convection in surface stellar layers. In this poster we present the results of applying the non-adiabatic analysis by Dupret et al. (2003) to δ Scuti stellar models computed by using the FST (Canuto et al. 1996, CGM) treatment of convection in the interior and in the atmosphere. We determine the amplitude ratios and phase difference for several bands in the Strömgren photometric system, and we compare the results obtained with the FST treatment and with the classical Mixing-length theory. We show that the differences in the external thermal structure are clearly reflected in the photometric phase differences.

scholarly journals Fourier Decomposition Parameters for the Halo RR Lyrae Variables U and V Caeli

1985 ◽  
Vol 82 ◽  
pp. 272-275
Author(s):  
L. Hansen ◽  
J. O. Petersen
Keyword(s):  
Light Curve ◽  
Light Curves ◽  
Published Data ◽  
Amplitude Ratios ◽  
Rr Lyrae Stars ◽  
Fourier Decomposition ◽  
Rr Lyrae ◽  
Lyrae Stars ◽  
Phase Differences

AbstractUBVRI light curves are obtained for the two halo RR Lyrae variables U Caeli with period 0.420 days (73 observations) and V Caeli with period 0.571 days (42 observations). It is shown that their light curve characteristics are very similar to those of field RR Lyrae stars.Fourier decompositions are studied for all five magnitudes and the resulting amplitude ratios and phase differences are discussed. The differences in the Fourier decomposition parameters between the five magnitudes are shown to be relatively small. Comparisons of the Fourier decomposition parameters for the two halo RR Lyrae stars with recently published data for field RR Lyrae stars show no systematic differences.

scholarly journals Nonadiabatic observables in β Cephei star models

1994 ◽  
Vol 162 ◽  
pp. 15-16 ◽  
Author(s):  
H. Cugier ◽  
W.A. Dziembowski ◽  
A.A. Pamyatnykh
Keyword(s):  
Radial Displacement ◽  
Horizontal Displacement ◽  
Stellar Atmosphere ◽  
Inertial Term ◽  
Amplitude Ratios ◽  
Effective Gravity ◽  
Star Models ◽  
Phase Differences ◽  
Hr Diagram

Results of the recent stability surveys (Dziembowski and Pamyatnykh 1993; Gautschy and Saio 1993) leave no doubts that the opacity mechanism is responsible for oscillations observed in β Cephei stars. The linear nonadiabatic analysis used to determine the instability domains in the HR diagram, yields also quantities that may be compared with observations. These nonadiabatic observables are evaluated from the complex eigenfunctions y(r) and f(r) describing variations of the radial displacement and the bolometric flux, respectively. Both y and f are very nearly constant within the stellar atmosphere. The eigenfunctions describing the horizontal displacement and variations of thermodynamical quantities may be expressed in terms of y and f. Since the linear eigenfunctions may be arbitrarily normalized, there are only two real independent observables. We may choose them to be and ψ = arg(f/y). Using static atmosphere models, with the inertial term included in the effective gravity, we may evaluate amplitude ratios and phase differences for integrated changes in directly measured parameters (Dziembowski 1977, Stamford and Watson 1981, Watson 1988).

A Multi-Path Tolerant Displacement Measurement System Using Radio Wave Phase Differences

2004 ◽  
Author(s):  
Nobuhiro Suzuki ◽  
Tadashi Mikoshiba ◽  
Atsushi Mogi
Keyword(s):  
Radio Wave ◽  
Measurement System ◽  
Measurement Method ◽  
Measurement Precision ◽  
Displacement Measurement ◽  
Experimental Results ◽  
Radio Waves ◽  
Measurement Systems ◽  
Wave Phase ◽  
Phase Differences

In quake-proof test facilities, multipoint displacement measurement systems are demanded to analyze quake-destroy mechanisms of structures. As a one of those systems, we have proposed a measurement method using radio wave phase differences. Observing carrier phases of radio waves from transmitters attached on measurement points, the displacement of measurement points can be measured. In this report, we propose an improved measurement method that uses redundant number of sensors to obtain multi-path tolerant capability. We will also report some new experimental results which show the proposed method has sub-centimeter measurement precision.

scholarly journals Comparison of the Pulsation Properties of the Rr Lyrae Stars in ω Centauri with those of Classical Cepheids

1985 ◽  
Vol 82 ◽  
pp. 276-279
Author(s):  
J. O. Petersen
Keyword(s):  
Quantitative Description ◽  
Light Curves ◽  
Powerful Method ◽  
Amplitude Ratios ◽  
Rr Lyrae Stars ◽  
Fourier Decomposition ◽  
Rr Lyrae ◽  
Classical Cepheids ◽  
Lyrae Stars ◽  
Phase Differences

In the last few years several studies have shown that Fourier decomposition technique is a powerful method for quantitative description of light curves of pulsation variables. This technique was introduced by Simon & Lee (1981), who showed that amplitude ratios and phase differences provide a very useful description of the Hertzsprung progression for classical Cepheids. Recently, Simon & Teays (1982) discussed 70 RR Lyrae field stars.In the present study I analyse 130 photographic mean light curves of RR Lyrae variables in ω Centauri taken from Martin (1938). I wish (i) to compare the Fourier decomposition parameters of the ω Cen RR Lyrae stars with those of the field variables as studied by Simon & Teays, (ii) to discuss the evidence for progression sequences among the ω Cen variables and (iii) to compare the basic pulsation properties of the RRab variables in ω Cen with those of classical Cepheids.

Sign in / Sign up

Export Citation Format

Share Document