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.
Results
Showing 1 to 20 of 46 for “"modems"”.
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Peak power reduction algorithms in ADSL modems
… systems, such as discrete multitone (DMT) modems and orthogonal frequency-division multiplexed (OFDM) terrestrial broadcast transmitters. Through simulation and test implementation on a state-of-the-art programmable ADSL development platform, this thesis pursues a suitable solution for …
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A case study in the deployment of digital access technologies : DSL vs. cable modems
… market. By applying a case study for Cable Modems and Digital Subscriber Line (DSL) modems, it is shown that the economic incentives to deploy new technologies are not necessarily aligned with the needs of the telecommunications consumer.
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Design and Performance Analysis of Wireless Networks
… conducted on a network of laptops with wireless modems.
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Infrastructure for large-scale tests in marine autonomy
… acoustic network. With these vehicles and modems we utilize compressive sensing, a recently developed framework for sampling sparse signals that offers dramatic reductions in the number of samples required for high fidelity reconstruction of a field. Our novel CS sampling techniques …
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An Image Compression Approach to Cooperative Processing for Swarming Autonomous Underwater Vehicles
… technologies—i.e. underwater acoustic modems—are extremely bandwidth limited as compared to land-based wireless technologies. Additionally, acoustic modem technologies are not advancing at the same high rate as computing technologies. Therefore, it is proposed that image compression …
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Design and analysis of a high-rate acoustic link for underwater video transmission
… the limit of commercially available acoustic modems, prototype acoustic modems based on phase coherent modulation/detection have demonstrated successful transmission at 30 kbps over a deep water channel. The key to bridging the remaining gap between the bit-rate needed for video transmission …
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Doppler channel emulation of high-bandwidth signals
… was created and tested using DVB-S2 satellite modems. Testing not only verified the functionality of the emulator but also showed that DVB-S2 modems are unequipped to handle the continuous spectral frequency shifts due to the Doppler effect. The emulator framework has considerable room for …
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Designing a wireless underwater optical communication system
Though acoustic modems have long been the default wireless communication method for underwater applications due to their long range, the need for high speed communication has prompted the exploration of non-acoustic methods that have previously been overlooked due to their distance limitations. One …
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Lossy compression and real-time geovisualization for ultra-low bandwidth telemetry from untethered underwater vehicles
… effects result in data rates for acoustic modems that are routinely as low as tens of bits per second. These data rates usually limit telemetry to state and health information, to the exclusion of mission-specific science data. In this thesis, I present a system designed for communicating …
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Lossy compression and real-time geovisualization for ultra-low bandwidth telemetry from untethered underwater vehicles
… effects result in data rates for acoustic modems that are routinely as low as tens of bits per second. These data rates usually limit telemetry to state and health information, to the exclusion of mission-specific science data. In this thesis, I present a system designed for communicating …
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A Study of Wireless Modem Performance Using Multiple Element Antennas
Next generation wireless modems are likely to be based on multiple antenna hardware platforms, following the demand for high data rate. In correlated channels Channel State Information (CSI) at the transmitter provides a significant capacity increase over conventional Multiple Input Multiple Output …
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Archimedean Screw Turbine Based Energy Harvester and Acoustic Communication in Well Site Applications
… Sensor Networks (WSNs) and underwater acoustic modems deployed in the various locations in the downhole environments. Parametric study on the number of blades, screw length, screw pitch, and rotational speed was conducted through CFD analysis using Ansys Fluent in order to determine the optimal …
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Signal absorption-based range estimator for undersea swarms
… Chip-scale atomic clocks (CSACs) and acoustic modems relative to other vehicle components limits large-scale swarms due to the associated cost-per-vehicle and communications infrastructure.
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Supervisory control of an autonomous underwater vehicle using an acoustic communication link
… locations on the ocean surface. Utility Acoustic Modems mounted on the moorings rebroadcast the binary data into the sea in the 12-17 kHz frequency band. The moving AUV detects the transmission, decodes the message, and carries out the command contained within. The operator's commands are …
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A study of the minimum shift keying modulation scheme
… of both coherent and non-coherent MSK modems. The literature on digital data transmission and MSK in particular is surveyed, and a comprehensive theoretical description of MSK is given. In addition, papers on the operation of MSK under non-linear conditions were studied, and their major …
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Design and experimental evaluation of an Autonomous Surface Craft to support AUV operations
… how an ASC tracks an AUV by configuring two modems together in a short baseline acoustic array. Results of this tracking show less than four meters of error under difficult real-world test conditions.
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Networking Requirements and Solutions for a TV WWW Browser
… public is mostly limited by today's analog modems through standard telephone lines. An inexpensive, easy-to-use Internet/WWW access service, able to handle bandwidth-intensive, multimedia-oriented WWW pages, is currently not available to the general public. Some concrete proposals, and even …
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Development of a Multiprocessor Data Telemetry System for Off-Road Vehicles
… facility. Both computers communicated using modems at data rates up to 9600 bits per second. The software included data compression, error checking, and software handshaking to maintain the reliability of the transmitted data. The laboratory results showed that this design technique would …
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Minimally intrusive strategies for fault detection and energy monitoring
… with a central processing unit via power line modems. In general, these systems determine the status of critical loads or systems using only electrical data. Thus, remotely located sensors are only employed in order to gather information that would be difficult, if not impossible, to obtain …
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Signal Absorption-Based Range Estimator for Undersea Swarms
… of Chip-scale Atomic Clocks (CSACs) and acoustic modems is limiting for large-scale swarms due to the cost-per-vehicle and communications structure. We propose a single vehicle with reliable navigation as a "leader" for a scalable swarm of lower-cost vehicles that receive signals via a single …
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