Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 120 for “"insertion loss"”.
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Active control methods for improving the insertion loss of acoustical enclosures
… is the implementation of passive transmission loss enclosures. An acoustical enclosure surrounds a noise source for the purpose of interrupting the noise transmission path. The effectiveness of these enclosures is, however, limited by various drawbacks. These drawbacks include leaks in the …
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A Comparative Study of Insertion Loss of Traffic Noise Barriers in Georgia
… Paragon panel 23-T, were evaluated in terms of insertion loss. Field test was conducted for the noise barriers recently installed as part of the Northwest Express Project in Georgia. The noise insertion loss was measured as noise difference in A-weighted decibels (dBA) immediately before and …
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An investigation into a method of designing insertion loss ladder filters avoiding incompatibilities
In this thesis Saraga’s design method for insertion loss filters is investigated, and an attempt made to assess its practicality. The basic filter design method (Darlington, Cauer) leads to numerical accuracy problems. Accepted methods for dealing with inaccuracy either replace the independent …
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Surface acoustic wave devices with low loss and high frequency operation
… addressed by STC were identified: lower insertion loss designs, higher operating frequencies and improved temperature dependent stability. A review of the temperature performance of alternative lower insertion loss designs,shows that greater use could be made of the on-site quartz growing …
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Plastic optical fibre couplers with wavelength division multiplexing capability for short-range peer-to-peer communication in networking and industrial applications
… which provides coarse tuning by varying the insertion depth of the coupling fibre into the backbone fibre to control the power received at each output port. The second is the reflector-length adjustment, which allows fine control by modifying the reflector length between the polished surfaces …
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Acoustic characteristics of fiberglass-lined circular ducts
… the techniques and procedures for measuring the insertion loss (with and without airflow) of fiberglass lined circular ducts. Regression analyses were conducted on the measured insertion loss data in order to provide regression equations that predict the performance of fiberglass lined circular …
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Design and performance of resonant cavities for communication systems. The theory and performance of resonant cavities for application-, in mobile radio and base-stations in the VHF and UHF bands are investigated.
… of which the most important factors are the Q, insertion loss and resonant frequency. However, a problem which frequently arises with cavity resonators is the accurate determination of these resonant characteristics complicated by the presence of coupling port, materials and various design and …
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Development of a test facility for making in-duct sound measurements according to Astm E477-1984
… can be significantly reduced. Only through insertion loss measurements can the appropriate silencer be determined for the desired noise reduction; This thesis involves the modification and qualification of the reverberation chamber in the Multi-Function Lab at the University of Nevada, Las …
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Development of a Weatherproof Windscreen for a Microphone Array
… a wind noise attenuation of at least 8 dB, an insertion loss of less than 1 dB from 5-1000 Hz, and a phase shift error of less than 3% over the same range. Computer simulations and experimental testing were used to select two basic designs. Four experimental tests consisting of wind noise …
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Switching mode power supply noise source impedance measurement and EMI filter characterization
… measuring methods. Two new methods, the insertion loss method and the signal injection method, are proposed to perform such a measurement. The insertion loss method utilizes the EMI emission as a signal source and derives the source impedance by measuring the emission attenuation caused …
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Optimal Design of an Enclosure for a Portable Generator
… The investigation follows the theories for insertion loss of a close fitting enclosure. The thesis examines the system behavior of a close fitting enclosure that most acoustic text books ignore and how the material stiffness, density and source-to-enclosure distance affect the insertion loss …
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Application Of Absorptive Treatments On Traffic Noise Barriers In Florida
… to determine the magnitude of parallel barrier insertion loss. The best fit equation model was then used to test against measured/model result and TNM prediction results for its validity. Absorptive materials were also studied such that 3 top of them were selected and recommended for Florida …
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Novel narrowband microstrip filters for wireless communications systems
… (shaip-cutoff frequency response, low insertion-loss, high return-loss, and high out-of-band isolation), compact size, low cost, and ease of integration in subsystem and systems. The analysis and modelling methods for these resonators includes a transmission-line theory, ABCD matrix, …
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Effects of duct source and termination impedance on the acoustic response characteristics of duct elements
… duct. The analytical methods to calculate the insertion-loss, noise reduction consider single reflection only inside the duct. Because of that, the analytical values of the insertion-loss and noise reduction do not match the experimental values well. When an anechoic termination is provided …
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Microultrasound Imaging of Tissue Dysplasia
… µUS transducer was measured to be 46% with an insertion loss of 21 dB. The bandwidth and insertion loss of a multiple matching layer µUS transducer was measured to be 59% and 18 dB respectively. The values were compared with an unmatched transducer which had a bandwidth and insertion loss of …
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Effect of opening size on the effectiveness of a noise enclosure on the side facing the opening
… a small opening area of 4 sq.inch reduced the insertion loss by 14 dB. On the other hand, at 500 Hz small openings did not significantly affect the Insertion Loss.
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Design multilayer bandpass filter using hairpin resonator for digital broadcasting
… coupled line band pass filter ,the passband insertion loss using FR4 Material is -5.651dB and when using RO3003 Material is -1.79dB .The passband return loss is -30.614dB for the FR4 material type and -18.52 dB for RO3003 material type. For multi layer band pass filter the passband insertion …
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Tunable microwave filters using ferroelectric thin films
… based on BST parallel plate capacitors show an insertion loss in line with the GaAs filters, which is also the lowest insertion loss of BST filters ever reported. Future work on improving the BST film and metal film loss at tens of gigahertz range is also discussed.
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Generation and characterization of spectrally factorable biphotons
… to 100km of standard optical fiber and with an insertion loss of only 2.8 dB. Compared with the typical method of using two temperature-stabilized equal-length fibers that incurs an insertion loss of 20 dB per fiber, the DCM approach achieves high spectral resolution in a much shorter …
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OPtO-MECHANICAL METHOD FOR SUB-MICRON MEASUREMENT OF FERRULE ROUNDNESS AND CONCENTRICITY
The insertion loss of fiber-optic components is one of the most important parameters that determine the performance of fiber-optic transmission systems. Some of the most widely used components in fiber optics systems are fiber optic connectors. To achieve a low loss connection between two optical …
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