Frequency Domain Description Of Interferogram Analysis

1984 ◽  
Vol 23 (4) ◽  
Author(s):  
K. H. Womack
Keyword(s):  
Frequency Domain ◽  
Domain Description

Estimation of Eccentric Distance for Four-Tooth End Mills Based on Amplitude Spectrum

2013 ◽  
Vol 278-280 ◽  
pp. 207-211
Author(s):  
Can Liu ◽  
Jing Quan Wu ◽  
Guang Hui Li ◽  
Guang Yu Tan
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Mathematical Reasoning ◽  
Spectral Characteristics ◽  
Amplitude Spectrum ◽  
Frequency Component ◽  
Milling Force ◽  
End Mills ◽  
Domain Description ◽  
Eccentric Distance

Time-domain expressions of nominal component and eccentric component that composing horizontal peripheral milling force are derived from geometry of down milling, they are periodic functions with fundamental frequencies same as tooth-frequency and spindle-frequency respectively. By expanding these two time-domain expressions with Taylor series, the frequency-domain description of periheral milling force is obtained. Further mathematical reasoning is exerted on this frequency-domain description, and it proved that as for four-tooth end mills, even-order harmonics of eccentric milling force do not exist, and the amplitude of spindle-frequency component be linear with eccentric distance, but irrelevant with eccentric angle. Above research results imply that the tooth-frequency component of four-tooth end mills is irrelevant with eccentricity, and that eccentric distance can be estimated with amplitudes of tooth-frequency and spindle-frequency components. Results of milling experiment imply that this eccentric-distance estimating method be effective. Spectral characteristics of eccentric milling force for four-tooth end mills are revealed with theory deduction, and the estimation algorithm for eccentric distance with simple calculation is present. Study conclusions can be used in eccentric-geometry estimating and in milling-force modeling.

Low-frequency electromagnetic fields in applied geophysics: Waves or diffusion?

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. W29-W40 ◽  
Author(s):  
Lars O. Løseth ◽  
Hans M. Pedersen ◽  
Bjørn Ursin ◽  
Lasse Amundsen ◽  
Svein Ellingsrud
Keyword(s):  
Frequency Domain ◽  
Low Frequency ◽  
Wave Theory ◽  
Signal Propagation ◽  
Dipole Source ◽  
Conductive Materials ◽  
Em Field ◽  
Domain Description ◽  
Ray Series ◽  
Low Frequency Waves

Low-frequency electromagnetic (EM) signal propagation in geophysical applications is sometimes referred to as diffusion and sometimes as waves. In the following we discuss the mathematical and physical approaches behind the use of the different terms. The basic theory of EM wave propagation is reviewed. From a frequency-domain description we show that all of the well-known mathematical tools of wave theory, including an asymptotic ray-series description, can be applied for both nondispersive waves in nonconductive materials and low-frequency waves in conductive materials. We consider the EM field from an electric dipole source and show that a common frequency-domain description yields both the undistorted pulses in nonconductive materials and the strongly distorted pulses in conductive materials. We also show that the diffusion-equation approximation of low-frequency EM fields in conductive materials gives the correct mathematical description, and this equation has wave solutions. Having considered both a wave-picture approach and a diffusion approach to the problem, we discuss the possible confusion that the use of these terms might lead to.

scholarly journals Frequency Domain Repercussions of Instantaneous Granger Causality

2021 ◽  
Author(s):  
Luiz Antonio Baccalá ◽  
Koichi Sameshima
Keyword(s):  
Time Series ◽  
Transfer Function ◽  
Frequency Domain ◽  
Granger Causality ◽  
Partial Directed Coherence ◽  
Directed Transfer Function ◽  
Vector Autoregressive Models ◽  
Vector Autoregressive ◽  
Standard Vector ◽  
Domain Description

Using Directed Transfer Function (DTF) and Partial Directed Coherence (PDC) in their information version, this paper extends their theoretical framework to incorporate instantaneous Granger Causality (iGC)’s frequency domain description into a single unified perspective. We show that standard vector autoregressive models allow portraying iGC’s repercussions associated with Granger Connectivity where interactions mediated without delay between time series can be easily detected.

Time domain frequency stability calculated from the frequency domain description :

1991 ◽  
Author(s):  
F L Walls ◽  
John Gary ◽  
Abbie O'Gallagher ◽  
Roland Sweet ◽  
Linda Sweet
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Frequency Stability ◽  
Domain Description

scholarly journals Polarization-Sensitive Electro-Optic Sampling of Elliptically-Polarized Terahertz Pulses: Theoretical Description and Experimental Demonstration

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 70-89 ◽  
Author(s):  
Kenichi Oguchi ◽  
Makoto Okano ◽  
Shinichi Watanabe
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Probe Pulse ◽  
Polarization State ◽  
Frequency Component ◽  
Phase Mismatch ◽  
Pockels Effect ◽  
Electro Optic ◽  
Domain Description ◽  
Elliptically Polarized

We review our recent works on polarization-sensitive electro-optic (PS-EO) sampling, which is a method that allows us to measure elliptically-polarized terahertz time-domain waveforms without using wire-grid polarizers. Because of the phase mismatch between the employed probe pulse and the elliptically-polarized terahertz pulse that is to be analyzed, the probe pulse senses different terahertz electric-field (E-field) vectors during the propagation inside the EO crystal. To interpret the complex condition inside the EO crystal, we expressed the expected EO signal by “frequency-domain description” instead of relying on the conventional Pockels effect description. Using this approach, we derived two important conclusions: (i) the polarization state of each frequency component can be accurately measured, irrespective of the choice of the EO crystal because the relative amplitude and phase of the E-field of two mutually orthogonal directions are not affected by the phase mismatch; and, (ii) the time-domain waveform of the elliptically-polarized E-field vector can be retrieved by considering the phase mismatch, absorption, and the effect of the probe pulse width. We experimentally confirm the above two conclusions by using different EO crystals that are used for detection. This clarifies the validity of our theoretical analysis based on the frequency-domain description and the usefulness of PS-EO sampling.

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