The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
R L Ameden - One of the best experts on this subject based on the ideXlab platform.
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activities of the cellular Telecommunications Industry Association microcell microsystems subcommittee regarding microcell technology
1st International Conference on Universal Personal Communications - ICUPC '92 Proceedings, 1992Co-Authors: R L AmedenAbstract:Discusses the activities of the Cellular Telecommunications Industry Association (CTIA) Microcell/Microsystems Subcommittee regarding microcell technology. The subcommittee was chartered to develop documents which would define the cellular carriers' viewpoints regarding microcells/microsystems and their applications to the equipment vendors. A brief history of the subcommittee is given, followed by summaries of the 'Microcell Guidelines' document and the 'Microcell/Microsystems Users' Performance Requirement'. >
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Activities of the Cellular Telecommunications Industry Association microcell/microsystems subcommittee regarding microcell technology
1st International Conference on Universal Personal Communications - ICUPC '92 Proceedings, 1992Co-Authors: R L AmedenAbstract:Discusses the activities of the Cellular Telecommunications Industry Association (CTIA) Microcell/Microsystems Subcommittee regarding microcell technology. The subcommittee was chartered to develop documents which would define the cellular carriers' viewpoints regarding microcells/microsystems and their applications to the equipment vendors. A brief history of the subcommittee is given, followed by summaries of the 'Microcell Guidelines' document and the 'Microcell/Microsystems Users' Performance Requirement'. >
P. Pepeljugoski - One of the best experts on this subject based on the ideXlab platform.
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development of system specification for laser optimized 50 spl mu m multimode fiber for multigigabit short wavelength lans
Journal of Lightwave Technology, 2003Co-Authors: P. Pepeljugoski, M. J. Hackert, J S Abbott, S E Swanson, Steven E Golowich, Albert John Ritger, P Kolesar, Y C Chen, P PleunisAbstract:This paper presents the scientific arguments used in the specification development process by the Telecommunications Industry Association (TIA) Working Group FO-2.2.1 to develop the new multimode fiber and vertical-cavity surface-emitting laser specifications for high-speed application in data communications. Numerous engineering and commercial tradeoffs are described. The specification minimizes the link failure rate and overall link cost through utilization of communication-theory-based modeling and experimental verification. This was balanced against the reality of manufacturing costs attempting to maximize the yield of individual link components. The specific application used as an example has 50-/spl mu/m graded-index multimode fiber operating at 10 Gb/s (e.g., 10 Gb/s Ethernet and fiber channel). The link performance is determined by the interaction of the fiber intermodal dispersion measured by the differential modal delay, and the transceiver launch distribution into the multimode fiber measured by encircled flux. A theoretically based model and the simulation approach that were used to simulate 40 000 links are described. The information from these simulations was used to determine the specification limits. In addition, sensitivity to the specification limits was evaluated. The experimental results of a round robin conducted by the TIA are presented, which confirm that the modeled performance would yield the expected results in actual practice.
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Measurements for enhanced bandwidth performance over 62.5-/spl mu/m multimode fiber in short-wavelength local area networks
Journal of Lightwave Technology, 2003Co-Authors: J.b. Schlager, M. J. Hackert, P. Pepeljugoski, J. GwinnAbstract:The Telecommunications Industry Association (TIA) FO-2.2.1 Working Group on the modal dependence of bandwidth has conducted Industrywide interlaboratory comparisons on measurements aimed at improving the bandwidth performance of short-wavelength, laser-based, multimode-fiber local area networks (LANs). Measurements of both transceiver encircled flux and fiber restricted-mode-launch bandwidth can together successfully predict an enhanced system performance, provided that the proper limiting criteria are selected. System performance is determined by a measurement of effective bandwidth and/or intersymbol interference. Recommendations for source and fiber selection criteria come from a risk analysis based on an extensive multilaboratory comparison involving 95 fibers and 69 laser transceivers. For this paper, enhanced system performance is defined as a performance that allows operation at a data rate of at least one gigabit per second over a 500-m length of 62.5/125-/spl mu/m graded-index glass fiber.
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Multimode fiber transceiver launch distribution : Results of an Industry round robin (TIA fo2.2 Task Group on the Modal Dependence of Bandwidth
1999Co-Authors: J.b. Schlager, M. J. Hackert, P. Pepeljugoski, M. Murphy, R. Neumann, J. Rice, J. GwinnAbstract:An Industry round robin conducted by the Telecommunications Industry Association FO-2.2 Task Group on the Modal Dependence of Bandwidth demonstrates good inter-laboratory agreement for measurements of transceiver encircled flux. In general, transceiver encircled flux directly correlates with the bandwidth performance of a given transceiver-fiber link; it also avoids the complications present in the raw near field data of the laser source. Four separate laboratories characterized seventeen laser transceivers. Uncertainties of plus or minus one standard deviation were no greater than 17 % of the mean encircled flux at 15 μm for any measured transceiver.
P Pleunis - One of the best experts on this subject based on the ideXlab platform.
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development of system specification for laser optimized 50 spl mu m multimode fiber for multigigabit short wavelength lans
Journal of Lightwave Technology, 2003Co-Authors: P. Pepeljugoski, M. J. Hackert, J S Abbott, S E Swanson, Steven E Golowich, Albert John Ritger, P Kolesar, Y C Chen, P PleunisAbstract:This paper presents the scientific arguments used in the specification development process by the Telecommunications Industry Association (TIA) Working Group FO-2.2.1 to develop the new multimode fiber and vertical-cavity surface-emitting laser specifications for high-speed application in data communications. Numerous engineering and commercial tradeoffs are described. The specification minimizes the link failure rate and overall link cost through utilization of communication-theory-based modeling and experimental verification. This was balanced against the reality of manufacturing costs attempting to maximize the yield of individual link components. The specific application used as an example has 50-/spl mu/m graded-index multimode fiber operating at 10 Gb/s (e.g., 10 Gb/s Ethernet and fiber channel). The link performance is determined by the interaction of the fiber intermodal dispersion measured by the differential modal delay, and the transceiver launch distribution into the multimode fiber measured by encircled flux. A theoretically based model and the simulation approach that were used to simulate 40 000 links are described. The information from these simulations was used to determine the specification limits. In addition, sensitivity to the specification limits was evaluated. The experimental results of a round robin conducted by the TIA are presented, which confirm that the modeled performance would yield the expected results in actual practice.
M. J. Hackert - One of the best experts on this subject based on the ideXlab platform.
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development of system specification for laser optimized 50 spl mu m multimode fiber for multigigabit short wavelength lans
Journal of Lightwave Technology, 2003Co-Authors: P. Pepeljugoski, M. J. Hackert, J S Abbott, S E Swanson, Steven E Golowich, Albert John Ritger, P Kolesar, Y C Chen, P PleunisAbstract:This paper presents the scientific arguments used in the specification development process by the Telecommunications Industry Association (TIA) Working Group FO-2.2.1 to develop the new multimode fiber and vertical-cavity surface-emitting laser specifications for high-speed application in data communications. Numerous engineering and commercial tradeoffs are described. The specification minimizes the link failure rate and overall link cost through utilization of communication-theory-based modeling and experimental verification. This was balanced against the reality of manufacturing costs attempting to maximize the yield of individual link components. The specific application used as an example has 50-/spl mu/m graded-index multimode fiber operating at 10 Gb/s (e.g., 10 Gb/s Ethernet and fiber channel). The link performance is determined by the interaction of the fiber intermodal dispersion measured by the differential modal delay, and the transceiver launch distribution into the multimode fiber measured by encircled flux. A theoretically based model and the simulation approach that were used to simulate 40 000 links are described. The information from these simulations was used to determine the specification limits. In addition, sensitivity to the specification limits was evaluated. The experimental results of a round robin conducted by the TIA are presented, which confirm that the modeled performance would yield the expected results in actual practice.
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Measurements for enhanced bandwidth performance over 62.5-/spl mu/m multimode fiber in short-wavelength local area networks
Journal of Lightwave Technology, 2003Co-Authors: J.b. Schlager, M. J. Hackert, P. Pepeljugoski, J. GwinnAbstract:The Telecommunications Industry Association (TIA) FO-2.2.1 Working Group on the modal dependence of bandwidth has conducted Industrywide interlaboratory comparisons on measurements aimed at improving the bandwidth performance of short-wavelength, laser-based, multimode-fiber local area networks (LANs). Measurements of both transceiver encircled flux and fiber restricted-mode-launch bandwidth can together successfully predict an enhanced system performance, provided that the proper limiting criteria are selected. System performance is determined by a measurement of effective bandwidth and/or intersymbol interference. Recommendations for source and fiber selection criteria come from a risk analysis based on an extensive multilaboratory comparison involving 95 fibers and 69 laser transceivers. For this paper, enhanced system performance is defined as a performance that allows operation at a data rate of at least one gigabit per second over a 500-m length of 62.5/125-/spl mu/m graded-index glass fiber.
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Multimode fiber transceiver launch distribution : Results of an Industry round robin (TIA fo2.2 Task Group on the Modal Dependence of Bandwidth
1999Co-Authors: J.b. Schlager, M. J. Hackert, P. Pepeljugoski, M. Murphy, R. Neumann, J. Rice, J. GwinnAbstract:An Industry round robin conducted by the Telecommunications Industry Association FO-2.2 Task Group on the Modal Dependence of Bandwidth demonstrates good inter-laboratory agreement for measurements of transceiver encircled flux. In general, transceiver encircled flux directly correlates with the bandwidth performance of a given transceiver-fiber link; it also avoids the complications present in the raw near field data of the laser source. Four separate laboratories characterized seventeen laser transceivers. Uncertainties of plus or minus one standard deviation were no greater than 17 % of the mean encircled flux at 15 μm for any measured transceiver.
Scott Isabelle - One of the best experts on this subject based on the ideXlab platform.
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Telecoil-mode hearing aid compatibility performance requirements for wireless and cordless handsets: magnetic signal-to-noise.
Journal of the American Academy of Audiology, 2020Co-Authors: Stephen D. Julstrom, Linda Kozma-spytek, Scott IsabelleAbstract:During the revision of the American National Standards Institute (ANSI) C63.19 and the development of the ANSI/Telecommunications Industry Association-1083 hearing aid compatibility standards, it became evident that additional data concerning user acceptance of interfering magnetic noises generated by wireless and cordless telephones were needed in order to determine the requirements for telecoil-coupling compatibility. Further insight was needed into the magnetic signal-to-noise (S/N) ratios required to achieve specific levels of telephone usability by hearing aid wearers. (A companion article addresses magnetic signal level requirements.) Test subjects used their own hearing aids. The magnetic signals were applied through large magnetic head-worn coils, selected for the field orientation appropriate for each hearing aid. After adjusting their aid's volume control to an acoustic speech reference, the subjects adjusted the applied magnetic signal level to find their Most Comfortable Level (MCL). Each subject then adjusted the levels of six of eight different representative interfering noises to three levels of subjective telephone usability: "usable for a brief call," "acceptable for normal use," and "excellent performance." Each subject's objective noise audibility threshold in the presence of speech was also obtained for the various noise types. The 57 test subjects covered an age range of 22 to 79 yr, with a self-reported hearing loss duration of 12 to 72 yr. All had telecoils that they used for at least some Telecommunications needs. The self-reported degree of hearing loss ranged from moderate to profound. A guided intake questionnaire yielded general background information for each subject. A test control box fed by prepared speech and noise recordings from computer files enabled the subject or the tester, depending on the portion of the test, to select A-weighting-normalized noise interference levels in 1.25 dB steps relative to the selected MCL. For each subject for each tested noise type, the values for the selected S/N ratios were recorded for the three categories of subjective usability and the objective noise threshold. About half of the test subjects needed a minimum 21 dB S/N ratio for them to consider their listening experience "acceptable for normal use" of a telephone. With a 30 dB S/N ratio, about 85% of the subjects reported normal use acceptability. Significant differences were apparent in the measured S/N user requirements among the noise types, though, indicating a deficiency in an A-weighted level measurement's ability to consistently predict the subjective acceptability of the various noises. An improved weighting function having both spectral and temporal components was developed to substantially eliminate these predictive inconsistencies. The interfering noise level that subjects chose for a telephone usability rating of "excellent performance" matched closely their objectively measured noise audibility threshold. A rating of "acceptable for normal use" was typically achieved at a 4 dB higher noise level, and a rating of "usable for a brief call," at a 10.4 dB higher noise level. These results did not relate significantly to noise type or to the subject's aided noise-in-speech hearing acuity. American Academy of Audiology.
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Telecoil-mode hearing aid compatibility performance requirements for wireless and cordless handsets: magnetic signal-to-noise.
Journal of The American Academy of Audiology, 2011Co-Authors: Stephen D. Julstrom, Linda Kozma-spytek, Scott IsabelleAbstract:In the development of the requirements for telecoil-compatible magnetic signal sources for wireless and cordless telephones to be specified in the American National Standards Institute (ANSI) C63.19 and ANSI/Telecommunications Industry Association-1083 compatibility standards, it became evident that additional data concerning in-the-field telecoil use and subjective preferences were needed. Primarily, the magnetic signal levels and, secondarily, the field orientations required for effective and comfortable telecoil use with wireless and cordless handsets needed further characterization. (A companion article addresses user signal-to-noise needs and preferences.) Test subjects used their own hearing aids, which were addressed with both a controlled acoustic speech source and a controlled magnetic speech source. Each subject's hearing aid was first measured to find the telecoil's magnetic field orientation for maximum response, and an appropriate large magnetic head-worn coil was selected to apply the magnetic signal. Subjects could control the strength of the magnetic signal, first to match the loudness of a reference acoustic signal and then to find their Most Comfortable Level (MCL). The subjective judgments were compared against objective in-ear probe tube level measurements. The 57 test subjects covered an age range of 22 to 79 yr, with a self-reported hearing loss duration of 12 to 72 yr. All had telecoils that they used for at least some Telecommunications needs. The self-reported degree of hearing loss ranged from moderate to profound. A total of 69 hearing aids were surveyed for their telecoil orientation. A guided intake questionnaire yielded general background information for each subject. A custom-built test jig enabled hearing aid telecoil orientation within the aid to be determined. By comparing this observation with the in-use hearing aid position, the in-use orientation for each telecoil was determined. A custom-built test control box fed by prepared speech recordings from computer files enabled the tester to switch between acoustic and magnetic speech signals and to read and record the subject's selected magnetic level settings. The overwhelming majority of behind-the-ear aids tested exhibited in-use telecoil orientations that were substantially vertical. An insufficient number of participants used in-the-ear aids to be able to draw general conclusions concerning the telecoil orientations of this style aid. The subjects showed a generally consistent preference for telecoil speech levels that subjectively matched the level that they heard from 65 dB SPL acoustic speech. The magnetic level needed to achieve their MCL, however, varied over a 30 dB range. Producing the necessary magnetic field strengths from a wireless or cordless telephone's handset in an in-use vertical orientation is vital for compatibility with the vast majority of behind-the-ear aids. Due to the very wide range of preferred magnetic signal levels shown, only indirect conclusions can be drawn concerning required signal levels. The strong preference for a 65 dB SPL equivalent level can be combined with established standards addressing hearing aid performance to derive reasonable source level requirements. Greater consistency between in-the-field hearing aid telecoil and microphone sensitivity adjustments could yield improved results for some users. American Academy of Audiology.
