Some measured frequency domain characteristics of the underwater vector and scalar acoustic field components with applications to communication receivers

2021 ◽  
Vol 150 (4) ◽  
pp. A155-A155
Author(s):  
Rami Rashid ◽  
Erjian Zhang ◽  
Ali Abdi
Keyword(s):  
Frequency Domain ◽  
Acoustic Field ◽  
Measured Frequency

Design of acoustic foam wedge panels by finite element frequency domain acoustical analysis

2019 ◽  
Vol 55 (3) ◽  
pp. 283-295
Author(s):  
Huoy-Shyi Tsay ◽  
Fung-Huei Yeh
Keyword(s):  
Finite Element ◽  
Numerical Method ◽  
Frequency Domain ◽  
Acoustic Field ◽  
High Frequency ◽  
Sound Absorption ◽  
Wedge Angle ◽  
Cross Sectional ◽  
Calculation Time ◽  
Acoustical Analysis

Acoustic foam wedge panels provide good sound absorption qualities in the mid and high frequency ranges. In this study, a finite element frequency domain acoustical analysis is used for analysis. Such a numerical method is more efficient than the earlier studies by saving the calculation time on the elements of the incident acoustic field. During the design of a wedge panel, the cross-sectional width and the area of one section of the wedge panel are kept the same throughout the study. By varying the wedge angle, the maximum sound absorption capability of the wedge foam can be found. It is concluded that in the interested frequency regions, 100–4000 and 2000–4000 Hz, the wedge foam with wedge angle of 31° has the excellent sound absorption capability.

Spectral IP studies of Finnish ore prospects

Geophysics ◽  
1992 ◽  
Vol 57 (12) ◽  
pp. 1545-1555 ◽  
Author(s):  
Heikki Vanhala ◽  
Markku Peltoniemi
Keyword(s):  
Grain Size ◽  
Frequency Domain ◽  
Frequency Band ◽  
Time Domain ◽  
Field Measurements ◽  
Coarse Grained ◽  
Thin Sections ◽  
Measured Frequency ◽  
The Time Domain ◽  
Phase Spectra

Spectral‐induced polarization (IP) field measurements, both in the frequency domain and in the time domain, were made at six early Proterozoic sulfide, oxide, and graphitic‐gneiss deposits in Finland. Core samples were also measured. The textures of the mineralizations were studied from thin and polished sections. Deposits with large differences in texture, such as graphitic gneiss and coarse‐grained disseminated sulfide, can be separated on the basis of their phasespectra time constants. A good correlation was found between the observed grain size in thin sections and the grain size calculated from the apparent, field‐survey phase spectra in the case of homogeneous, disseminated textures. The measured frequency‐domain phase spectra, and phase spectra calculated from the time‐domain Cole‐Cole parameters are very similar in a comparable frequency band. For both techniques, the phase maximum lies beyond the lowest measured frequency. The possibilities to expand the frequency band to levels low enough to reach the phase maximum seem to be restricted. However, the results indicate that contrasts between spectra from different ore‐texture types also appear at higher frequencies.

A methodology for true comparison of analytical and measured frequency domain spectra in random PWM converters

1999 ◽  
Vol 14 (3) ◽  
pp. 578-586 ◽  
Author(s):  
M.M. Bech ◽  
J.K. Pedersen ◽  
F. Blaabjerg ◽  
A.M. Trzynadlowski
Keyword(s):  
Frequency Domain ◽  
Pwm Converters ◽  
Measured Frequency

Design of High-Precision Frequency Meter

2013 ◽  
Vol 329 ◽  
pp. 364-367
Author(s):  
Li Mian Ren ◽  
Li Xia Wang ◽  
Ming Zhe Wei
Keyword(s):  
Frequency Domain ◽  
High Precision ◽  
Complete System ◽  
Control Program ◽  
Periodic Signal ◽  
Software System ◽  
Measured Frequency ◽  
Frequency Meter ◽  
Precision Frequency ◽  
Hardware And Software System

Frequency meter measured frequency of analog periodic signal in its frequency domain and used the software control program to replace the complex outside counting circuit. ARM7 development board, LPC2103 chip, and AD9833 chip made up of a complete system. This paper gave the designing schemes of hardware and software system and analyzed experiment results, which prove that this design reaches expectant target with less hardware and simpler structure.

Correction to "The analysis of slug tests in the frequency domain" (WRR 25(11), pp. 2388-2396

1990 ◽  
Vol 26 (8) ◽  
pp. 1863-1863
Author(s):  
Paul Marschall ◽  
Baldur Barczewski
Keyword(s):  
Frequency Domain ◽  
Slug Tests
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