scholarly journals Precise measurement of phase difference and amplitude ratio with an interchange reference method

1983 ◽  
Vol 73 (S1) ◽  
pp. S23-S23
Author(s):  
G. S. K. Wong
Keyword(s):  
Phase Difference ◽  
Precise Measurement ◽  
Amplitude Ratio ◽  
Reference Method

scholarly journals Performance Degradation in Cross-Eye Jamming Due to Amplitude/Phase Instability between Jammer Antennas

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5027
Author(s):  
Je-An Kim ◽  
Joon-Ho Lee
Keyword(s):  
Performance Analysis ◽  
Phase Difference ◽  
Taylor Expansion ◽  
Amplitude Ratio ◽  
Random Variables ◽  
Performance Degradation ◽  
Analytical Performance ◽  
Phase Instability ◽  
Gaussian Random Variables ◽  
First Order

Cross-eye gain in cross-eye jamming systems is highly dependent on amplitude ratio and the phase difference between jammer antennas. It is well known that cross-eye jamming is most effective for the amplitude ratio of unity and phase difference of 180 degrees. It is assumed that the instabilities in the amplitude ratio and phase difference can be modeled as zero-mean Gaussian random variables. In this paper, we not only quantitatively analyze the effect of amplitude ratio instability and phase difference instability on performance degradation in terms of reduction in cross-eye gain but also proceed with analytical performance analysis based on the first order and second-order Taylor expansion.

scholarly journals Mode Discrimination in Nonradially Oscillating Stars From Light, Colour and Velocity Observations

1980 ◽  
Vol 58 ◽  
pp. 371-376
Author(s):  
L.A. Balona ◽  
R.S. Stobie
Keyword(s):  
Radial Velocity ◽  
Phase Difference ◽  
Spherical Harmonic ◽  
Amplitude Ratio ◽  
Harmonic Mode ◽  
Instability Strip ◽  
Nonradial Oscillation ◽  
Mode Discrimination ◽  
Velocity Variations

AbstractExpressions for the amplitudes and phases of the light, colour and radial velocity variations are derived for a star in nonradial oscillation. For stars in the cepheid instability strip the spherical harmonic mode of the oscillation can be obtained from the phase difference between the light and colour variations. For 3 Cep stars the mode can be estimated from the amplitude ratio of the light and colour variations.

Vibration Parameter Analysis of Non-Harmonic Vibration Conveyor

2013 ◽  
Vol 694-697 ◽  
pp. 61-64
Author(s):  
Zhi Ying Qin ◽  
Yao Liu
Keyword(s):  
Phase Difference ◽  
Amplitude Ratio ◽  
Parameter Analysis ◽  
Harmonic Vibration ◽  
Dynamics Model ◽  
Bulk Materials ◽  
Optimum Frequency ◽  
Single Degree Of Freedom ◽  
Harmonic Components ◽  
Vibration Parameters

For the non-harmonic vibration conveyor, a single-degree-of-freedom dynamics model is built for the horizontal motion of bulk materials, in which the dry friction force is piecewise nonsmooth. The effect on conveying velocity is studied for six vibration parameters in the excitation force with two harmonic components. The conveying velocity increases with the increase of frequency and amplitude, but the optimum frequency ratio is 2, and the optimum amplitude ratio approaches 1/3. The initial phase has no effect on conveying velocity, and the effect of phase difference is periodic, i.e. the forward conveying is best on phase difference π/2, and the backward conveying is best on phase difference -π/2.

The upper frequency limit for the binaural localization of a pure tone by phase difference

1940 ◽  
Vol 128 (852) ◽  
pp. 293-305 ◽  
Keyword(s):  
Phase Difference ◽  
Pure Tone ◽  
Amplitude Ratio ◽  
Median Plane ◽  
Rapid Onset ◽  
Continuous Phase ◽  
Phase Changes ◽  
Considerable Difficulty ◽  
Intensity Changes ◽  
Binaural Localization

It is well known that if a pure tone is presented binaurally so that its intensity is the same in each ear, and there is no phase difference between the notes at the ears, the resulting sensation is that of a source of sound located in the median plane and situated is that of a source of sound located in the median plane and situated either within the skull or outside it. If a difference of phase between the notes is gradually introduced without altering their intensities, and the frequency of the tone is, say, 800 cyc. /sec., then the source appears to move laterally towards the side of the ear in which the phase is made to lead. According to some observers, the movement is on a horizontal circular arc centred between the ears, while others consider it to be along a line joining the ears. There is general agreement among workers on localization that considerable difficulty exists in the detection of such movements at frequencies above 800 cyc. /sec., and that their extent is more limited, but they disagree as to the frequency above which the lateral motion ceases to be noted. Stewart (1920) obtained movement at 1280 cyc. /sec., but not 1536 cyc. /sec.; Banister (1925) found movements at 1040 and 1345 cyc. /sec., but anomalous in character. On the other hand, von Hornbostel and Wertheimer (1920) state that at about 800 cyc. /sec., the lateral movement no longer extends 90° left and right, but decreases as the frequency increases, and should reach zero at 17,000 cyc. /sec. Halverson (1927) found that observable right and left effects appear to be present up to the upper auditory limit. Below 1400 cyc. /sec. judgments of direction are fairly consistent, between 1400 and 3000 cyc. /sec. there is no particular difficulty if allowance is made for the more rapid onset of fatigue at these frequencies. Above 3000 cyc. /sec. lateral effects are still observable, though median localization is extremely difficult to achieve. Hartley (1919) gave theoretical curves showing the phase difference produced at the ears by sources of various frequencies at different distances from the head. According to these, above 650 cyc. /sec. the maximum movement of the apparent source would be less than 90°, though at 1860 cyc. /sec. there should still be about 27° of movement on either side of the median plane. These curves have been checked experimentally by Firestone (1930), who found for three frequencies the phase difference and amplitude ratio of the sounds entering the ears of a man-shaped wax dummy from a source at varying azimuths around the head and at different distances from it. The phase differences found were in good agreement with the values calculated by Hartley. Various methods have been used to present the notes to the ears and to vary the phase difference between them. In the experiments of Halverson the sounds were produced by a tuning fork and led to the ears through tubes, in one of which was incorporated a sliding section to vary its length and thus the phase difference at the ears. An objection to this is the possibility of resonances in the tubes, different on both sides on account of their different lengths, so that intensity changes might occur as well as changes oh phase. Stewart, and Banister, used notes generated electrically and presented to the ears by telephones. Continuous phase changes could be made with their generators, but the purity of the resulting notes was doubtful.

Study of the Multiaxial Fatigue Life Influencing Factors Based on the Critical Plane Approach

2011 ◽  
Vol 295-297 ◽  
pp. 2314-2320
Author(s):  
Peng Min Lv ◽  
Chun Juan Shi
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Phase Difference ◽  
Amplitude Ratio ◽  
Uniaxial Stress ◽  
Multiaxial Fatigue ◽  
Normal Strain ◽  
Critical Plane ◽  
Proportional Loading ◽  
Maximum Shear Strain

The tension-torsion thin walled tube specimens were used as the researching object in this paper. The method of determination to the critical plane which has the maximum normal strain and maximum shear strain was expounded. The strain state on the critical plane under non-proportional loading was analyzed, and the unified prediction model was used to calculate the fatigue life. In order to research the influence of phase difference on fatigue life under the non-proportional loading, the relation of the equivalent strain and the phase difference in different positive strain amplitude and different strain amplitude ratio were analyzed. It’s found that the dangerous phase difference which has the shortest fatigue life is in direct relation with the strain amplitude ratio. The general formula of dangerous phase difference is presented. Through the material mechanics performance and fatigue parameters of uniaxial stress state, the coefficients in the formula can be obtained and the coefficients of 15 kinds of common materials are given for practical application.

New technique in plasma polarimetry: Evolution equations for angular parameters ‘amplitude ratio–phase difference’ of polarization ellipse

2011 ◽  
Vol 78 (1) ◽  
pp. 87-91 ◽  
Author(s):  
YURY A. KRAVTSOV ◽  
JANUSZ CHRZANOWSKI ◽  
BOHDAN BIEG
Keyword(s):  
Numerical Modeling ◽  
Phase Difference ◽  
Evolution Equations ◽  
Amplitude Ratio ◽  
Direct Calculation ◽  
Polarization Ellipse ◽  
New Technique ◽  
Stokes Vector ◽  
Field Equations ◽  
Orthogonal Components

AbstractNew technique is suggested in plasma polarimetry: Differential equations for angular parameters of polarization ellipse, characterizing the amplitude ratio and the phase difference between orthogonal components of the wave field. Equations for angular variables ‘amplitude ratio–phase difference’ are derived, which allow direct calculation of the parameters of polarization ellipse, omitting solutions for the Stokes vector. The simplest analytical solutions are presented for the pure Faraday and the pure Cotton–Mouton effects. Behavior of angular parameters in the homogeneous and inhomogeneous plasmas is illustrated by numerical modeling in conditions when the Faraday and Cotton–Mouton effects are large enough and comparable in strength.

On the Conditions under which Energy can be Extracted from an Air Stream by an Oscillating Aerofoil

1954 ◽  
Vol 4 (1) ◽  
pp. 54-68 ◽  
Author(s):  
N. C. Lambourne
Keyword(s):  
Phase Difference ◽  
Amplitude Ratio ◽  
Vortex Sheet ◽  
Frequency Parameter ◽  
The Other ◽  
Positive Energy ◽  
Two Dimensional ◽  
Zero Energy ◽  
Upper Limit ◽  
Air Stream

SummaryA simple system is considered in which a two-dimensional aerofoil in an air stream performs a coupled oscillation in pitching and vertical translation. An expression for the energy transferred from stream to aerofoil is derived as a function of the frequency parameter, amplitude ratio and phase difference, and the conditions under which positive energy can be extracted from the stream are investigated. The connection between the case of zero energy transfer, and the critical flutter state is noted.Attention is confined to the incompressible case and diagrams show the results obtained when the air loads are obtained from (i) vortex sheet theory and (ii) the classical set of constant derivatives.Vortex sheet theory leads to the conclusion that, provided that the amplitude ratio and phase difference satisfy certain conditions, energy can be extracted from the stream for all values of the frequency parameter. On the other hand, the use of a set of constant derivatives places an upper limit on the values of the frequency parameter for the extraction of energy.

Sign in / Sign up

Export Citation Format

Share Document