scholarly journals Propagation of narrow-band-high-frequency clicks: Measured and modeled transmission loss of porpoise-like clicks in porpoise habitats

2010 ◽  
Vol 127 (1) ◽  
pp. 560-567 ◽  
Author(s):  
Stacy L. DeRuiter ◽  
Michael Hansen ◽  
Heather N. Koopman ◽  
Andrew J. Westgate ◽  
Peter L. Tyack ◽  
...  
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Narrow Band

Elimination of a High-Frequency Narrow-Band Noise Component in a Low-Noise Automobile Wind Tunnel

1996 ◽  
Author(s):  
Wilhelm von Heesen ◽  
Norbert Lindener ◽  
Wolfgang Neise
Keyword(s):  
Wind Tunnel ◽  
High Frequency ◽  
Narrow Band ◽  
Low Noise ◽  
Noise Component ◽  
Narrow Band Noise ◽  
Band Noise

scholarly journals Kajian Eksperimental Koefisien Redaman Akustik Bahan Pelapis Plat Dek Kapal

2018 ◽  
Vol 3 (1) ◽  
pp. 41
Author(s):  
Wibowo Harso Nugroho ◽  
Nanang J.H. Purnomo ◽  
Hardi Zen ◽  
Andi Rahmadiansah
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Transmission Loss ◽  
Base Material ◽  
Sound Insulation ◽  
Insulation Material ◽  
Base Materials ◽  
Specimen Material ◽  
Ship Classification ◽  
Technical Assessment

With the increasingly strict requirements of the ship classification bureau for permissible noise limits to allow passengers and crew to be more comfortable and secure a technical assessment is required to address the characteristics of the noise. A noise beyond the standard allowed in the vessel can be a problem to the ship operators. This noise problem will greatly affects the crews' comfort and passengers. One method to reduce the noise on a ship is to use sound insulation. This paper describes the method for determining the absorption coefficient α and the transmission loss (TL) through an acoustic test of a concrete insulation in the laboratory. The test was conducted by using the method of impedance tube where a speciment response measured by a microphone. In general, the properties of this insulation material remains as the main base material which is concrete. it has been found that the transmission loss value (TL) is in the range of 10 - 50 dB whereas for the base material the concrete is around 22 - 49 dB but the absorption coefficient α of the specimen material is much higher than the material of the base material especially in high frequency, which ranges from 0.15 to 0.97, whereas for concrete base materials have absorbent coefficient α ranges from 0.01 to 0.02.

Advanced Low Df Dry film Build-up Material on Glass panel for 5G application

2020 ◽  
Vol 2020 (1) ◽  
pp. 000201-000205
Author(s):  
Takenori Kakutani ◽  
Zhong Guan ◽  
Yuya Suzuki ◽  
Muhammad Ali ◽  
Serhat Erdogan ◽  
...  
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Core Material ◽  
Wave Band ◽  
Organic Substrates ◽  
Frequency Filter ◽  
Transmission Characteristics ◽  
Glass Panel ◽  
Low Loss ◽  
Dry Film

Abstract This paper describes the demonstration of a low loss substrate (laminated glass) for high-frequency transmission using a dry film build-up material with low loss tangent (Df). This paper also evaluates filter characteristics and dielectric characteristics of the substrate in the mm-Wave band. The advanced low loss dry film build-up material was newly developed, and applicable to high frequency transmission. This material has a Df of 0.0025 at 10 GHz and also exhibits excellent adhesion and electrical reliability required for advanced dielectric materials. In addition, glass was used as a core material in this paper because of its excellent signal transmission characteristics compared to silicon wafers or organic substrates. To demonstrate the benefit of low loss materials for high frequency transmission, passive components for high frequency filter substrates were fabricated using - 6-inch square thin (0.2mm) glass panel with various build-up materials (Material A with a Df of 0.0025, and Material B with a Df 0.0042 at 10 GHz) laminated. Copper wiring patterns on the dielectric layers were fabricated by a semi-additive process (SAP). Circuit patterns with low pass filters and band pass filters were also fabricated. First, transmission characteristics and characteristic impedances were measured to check the electrical performance. The measured lowest transmission loss of < 1.43 dB at 39 GHz were achieved when Material A was applied as the build-up material. Second, biased-highly accelerated stress test (bHAST) was conducted to evaluate the reliability performance of the substrates with two build-up materials, Material A and a conventional material. The test condition was based on the JEDEC level 2 standard. The substrate with Material A retained good insulation properties over 300 hours of bHAST treatment, demonstrating its excellent insulating performance. In summary, Material A has been shown in this paper to exhibit reduced transmission loss in high-frequency filter substrates at millimeter wave frequencies.

Disparity Modulation Sensitivity for Narrow-Band-Filtered Stereograms Viewed out of the Plane of Fixation

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 94-94
Author(s):  
B Lee ◽  
B J Rogers
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Significant Interaction ◽  
Narrow Band ◽  
Low Frequency ◽  
Frequency Pattern ◽  
Spatial Frequencies ◽  
Size Disparity ◽  
Random Dot Stereograms

Narrow-band-filtered random-dot stereograms were used to determine stereo thresholds for detecting sinusoidal disparity modulations. These stereograms were designed to stimulate selectively channels tuned to luminance and corrugation spatial frequencies (Schumer and Ganz, 1979 Vision Research19 1303 – 1314). Thresholds were determined for corrugation frequencies ranging from 0.125 to 1 cycle deg−1, luminance centre spatial frequencies ranging from 1 to 8 cycles deg−1 and disparity pedestal sizes ranging from −32 to +32 min arc. For small disparity pedestals, lowest modulation thresholds were found around 0.5 cycle deg−1 corrugation frequency and 4 cycles deg−1 luminance centre spatial frequency. For large disparity pedestals (±32 arc min), lowest thresholds were shifted towards the lower corrugation frequencies (0.125 cycle deg−1) and lower luminance frequencies (2 cycles deg−1). There was a significant interaction between luminance spatial frequency and disparity pedestal size. For small pedestals, lowest thresholds were found with the highest luminance frequency pattern (4 cycles deg−1). For large pedestals, best performance shifted towards the low-frequency patterns (1 cycle deg−1). This effect demonstrates a massive reduction in stereo-efficiency for high-frequency patterns in the luminance domain at large disparity pedestals which is consistent with the ‘size-disparity relation’ proposed by previous researchers.

scholarly journals Raising your voice: evolution of narrow-band high-frequency signals in toothed whales (Odontoceti)

2018 ◽  
Vol 126 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Anders Galatius ◽  
Morten Tange Olsen ◽  
Mette Elstrup Steeman ◽  
Rachel A Racicot ◽  
Catherine D Bradshaw ◽  
...  
Keyword(s):  
High Frequency ◽  
Narrow Band

Reduction of Vibration and Noise Generated by Planetary Ring Gears in Helicopter Aircraft Transmissions

1973 ◽  
Vol 95 (4) ◽  
pp. 1149-1158 ◽  
Author(s):  
Thomas Chiang ◽  
R. H. Badgley
Keyword(s):  
High Frequency ◽  
Narrow Band ◽  
Vibration Energy ◽  
Ring Gear ◽  
Noise Sources ◽  
Rotor Drive ◽  
Design Changes ◽  
Planetary Ring ◽  
Gear Meshes ◽  
Very High

Rotor-drive gearboxes are major noise sources in helicopter aircraft. Narrow-band examination of this noise often indicates the presence of several or more very high, narrow noise peaks, which are located at gearbox mesh frequencies or their multiples. Important exceptions are sideband noise components, located so near the main signal component as to be indistinguishable except by very narrow band reduction. Noise of this type is most effectively treated through a systematic study of the flow of high-frequency vibration energy in the drive train. Such studies should examine the mechanism by which gear meshes generate vibrations, and the vibration response of the gearbox components which support the gears. Results of such calculations are presented for the planetary reduction ring-gear casing elements in the Boeing-Vertol CH-47 forward rotor-drive gearbox and the Bell UH-1D main rotor-drive gearbox. The calculations indicate logical reasons why noise is generated. Typical ring-gear casing design changes are examined for noise reduction.

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