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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Application of a High Data Rate Modem (HDRM)

Orndorff, Tim, Puri, Amit, Smiley, Mike, Connell, John 10 1900 (has links)
ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / A traditional Receiver, Modulator, Bit Synchronizer, Frame Synchronizer and Front-End Processor (FEP) with local RAID storage from numerous satellite ground station equipment providers is typically used to satisfy current needs in mission ground stations. The development of Software Defined Radios (SDRs) with reprogrammable personalities has led to the consolidation of these processing elements, and will become the standard for years to follow. CVG-Avtec Systems, Inc. has been a pioneer in the SDR industry, integrating several ground station functions into a one system solution. Its High Data Rate Modem (HDRM) architecture replaces racks of previous generation equipment, providing greater functionality in a smaller footprint. The Field Programmable Gate Array (FPGA) based HDRM is a one system solution that inputs Intermediate Frequency (IF) data and outputs packetized data over IP for data distribution. These new architectures are capitalizing on the revolution in electronics and networking technologies. This paper will discuss the architecture of the HDRM and how it optimizes ground station data processing in a high-rate environment.
22

Contributions to Data Postprocessing in Sending Samples Parameters at Critical Moments on Unmanned Aerial

Rubio, Manuel Sánchez, Armengod, Rafael G., de-Marcos, Luis, Martinez, José-Javier 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / In this paper we investigate the different stages that allow us to create a model that would provide a better understanding of what happens on certain parameters that measure physical quantities related to the behavior of both, burst and reaction, unmanned aircraft as well as unmanned helicopters based on a data transmission to land via radio modem.
23

Fascist di-visions of enjoyment and the perverse remainder : a psychoanalytic study

Vadolas, Antonios January 2006 (has links)
Under the shade of escalating violence and fundamentalism, our epoch's diffused aura of liberalism supposedly tolerates difference, by exorcising the evil phantasms of totalitarianism, in favour of a liberal and humane post-modem order. Consequently, behind contemporary versions of evil, one demonises modem 'fascists', 'totalitarian threats', and 'Hitlers'. As if not obscure enough, fascist evil has been equivocally linked with perversion. Considering this link a tenebrous enigma, my thesis suggests that psychoanalysis can successfully elucidate its problematic and feeble basis, by reappraising previous narratives from a number of different discourses that inscribe the liaison between fascism and perversion in their representational stage. In a first approach, the present study dissects texts as heterogeneous, as film, social theory, political philosophy, and psychoanalysis. This is to show that, despite the divergent speculative angle that each discourse espouses, perversion is a common exegetic thread, intertextually sewing their narratives. The objective of my criticism that goes through psychoanalysis, without, however, exempting it from this criticism, is to reveal that both fascism and perversion implicate the non-symbolisable kernel in politics, which becomes the source of their mystification. My thesis argues that the fascist does not take the same discursive position, as the pervert does, regarding this symbolic gap. The first is interested in domination, drawn from the superiority of his ideology's master signifier, whereas the latter is interested in excavating the emptiness of any master signifier and in constantly provoking prefabricated knowledge, similarly to the hysteric. Apart from the level of discourse, on the ethical level, I disengage the view that sees Sade and the Nazi officer, as emblematic figures of a Kantian ethical gesture. Considering the imaginary hypostasis of their ethical performance, I argue that personal interests, fantasies and desires, determine the austerity of their ethical duty. Yet, the fantasies of Sade and Nazism are incongruent, insomuch as they are organised by antithetical ideals. Finally, I develop a new rhetoric, de-pathologised and de-ideologised, regarding the structure of the so-called pervert, introducing new vocabularies and directions for psychoanalytic research that further distance the pervert, or whom I call the extra-ordinary subject, from fascist politics and, instead, expose his diachronic "fascist" isolation from the social edifice. This reveals the fruitful alternatives that can stem from a 'return to Freud cum Lacan, which supports a flexible on-going reformulation of psychoanalytic knowledge.
24

Design of a High Data Rate Audio Band OFDM Modem

Navalekar, Abhijit C 18 April 2006 (has links)
Land mobile radio technology (LMR) has existed since the early 1920's. The most visible manifestation of this technology is the handheld VHF/UHF radios also referred to as 'walkie-talkie'. These handheld devices are one of the most ubiquitous forms of radio communication systems. Most of them are designed for transmitting analog voice signals. Due to an increase in the amount of digitized analog signals over the past few years complemented by a need for transmitting pure digital data, there has been a desire to transmit digital data. There are methods which allow the analog radios to transmit digital data without any modifications; however the data rate achievable using these methods is very low. In contrast, the digital variants of these hand-held radios are capable of transmitting digital data at comparatively higher data rates. However they are expensive and require major infrastructure overhauls. In this thesis, a prototype modem was developed which interfaces with an analog radio without any modifications to the radio. Furthermore, the data rates achievable are comparable with those achieved using digital radios. The modem uses Orthogonal Frequency Division Multiplexing (OFDM) technique to generate an audio band signal which is fed to the radio. The OFDM technique used to generate the audio band signal from data bits ensures maximum bandwidth efficiency. The developed modem is capable of communicating over Ethernet connection. It uses a RJ 45 interface to connect to a data source.
25

Adaptive multilevel quadrature amplitude radio implementation in programmable logic

Aspel, Daniel T 29 April 2004
Emerging broadband wireless packet data networks are increasingly employing spectrally efficient modulation methods like Quadrature Amplitude Modulation (QAM) to increase the channel efficiency and maximize data throughput. Unfortunately, the performance of high level QAM modulations in the wireless channel is sensitive to channel imperfections and throughput is degraded significantly at low signal-to-noise ratios due to bit errors and packet retransmission. To obtain a more robust physical layer, broadband systems are employing multilevel QAM (M-QAM) to mitigate this reduction in throughput by adapting the QAM modulation level to maintain acceptable packet error rate (PER) performance in changing channel conditions. This thesis presents an adaptive M-QAM modem hardware architecture, suitable for use as a modem core for programmable software defined radios (SDRs) and broadband wireless applications. The modem operates in burst mode, and can reliably synchronize to different QAM constellations burst-by-burst. Two main improvements exploit commonality in the M-QAM constellations to minimize the redundant hardware required. First, the burst synchronization functions (carrier, clock, amplitude, and modulation level) operate reliably without prior knowledge of the QAM modulation level used in the burst. Second, a unique bit stuffing and shifting technique is employed which supports variable bit rate operation, while reducing the core signal processing functions to common hardware for all constellations. These features make this architecture especially attractive for implementation with Field Programmable Gate Arrays (FPGAs) and Application-Specific Integrated Circuits (ASICs); both of which are becoming popular for highly integrated, cost-effective wireless transceivers.
26

Adaptive multilevel quadrature amplitude radio implementation in programmable logic

Aspel, Daniel T 29 April 2004 (has links)
Emerging broadband wireless packet data networks are increasingly employing spectrally efficient modulation methods like Quadrature Amplitude Modulation (QAM) to increase the channel efficiency and maximize data throughput. Unfortunately, the performance of high level QAM modulations in the wireless channel is sensitive to channel imperfections and throughput is degraded significantly at low signal-to-noise ratios due to bit errors and packet retransmission. To obtain a more robust physical layer, broadband systems are employing multilevel QAM (M-QAM) to mitigate this reduction in throughput by adapting the QAM modulation level to maintain acceptable packet error rate (PER) performance in changing channel conditions. This thesis presents an adaptive M-QAM modem hardware architecture, suitable for use as a modem core for programmable software defined radios (SDRs) and broadband wireless applications. The modem operates in burst mode, and can reliably synchronize to different QAM constellations burst-by-burst. Two main improvements exploit commonality in the M-QAM constellations to minimize the redundant hardware required. First, the burst synchronization functions (carrier, clock, amplitude, and modulation level) operate reliably without prior knowledge of the QAM modulation level used in the burst. Second, a unique bit stuffing and shifting technique is employed which supports variable bit rate operation, while reducing the core signal processing functions to common hardware for all constellations. These features make this architecture especially attractive for implementation with Field Programmable Gate Arrays (FPGAs) and Application-Specific Integrated Circuits (ASICs); both of which are becoming popular for highly integrated, cost-effective wireless transceivers.
27

The development of software for a faxmoden card

Stuurman, Christian Phillip January 1995 (has links)
Thesis (M.Tech (Electrical Engineering))--Cape Technikon, 1995 / This thesis describes the design and development ofsoftware for a FAXMODEM card for a personal computer. The software was developed to enable the designed FAXMODEM card to transmit and receive facsimiles independent of the host personal computer.
28

FSK modem s implementací protokolu AX.25 / FSK modem with AX.25 protocol

Vojtek, Michal January 2011 (has links)
The purpose of this thesis is to design FSK modem for Packet communication. In accordance with accessible literature was constructed functioning circuit schema and subsequently there was constructed a motherboard which is mainly assembled from SMD technology. It makes this modem mobile and very easy usable in terrain. Modem communicates with PC via USB bus. Also this bus is used as power source for this device. Communication between modem and PC is realized by KISS protocol and connection with tranciever is realized by AX.25 protocol.
29

Bezpečnostní systém s využitím mobilních sítí / Security system using mobile networks

Svoboda, Adam January 2015 (has links)
This master´s thesis deals with design of security system, which transmits captured video using mobile systems. There are chosen representatives of cameras and motion sensors that could be used in the construction. The thesis also deals with the theoretical design of the transmission system, which consists of a camera, a motion sensor, an USB modem and a microprocessor, that manages all operations. There is also a proposed block diagram of a communication method. The security system is designed and tested in various conditions.
30

USB Attached Network Performance : Uplink Performance

Di, Shuang January 2009 (has links)
More and more people all over the world are using a USB modem to connect to the Internet. This is especially true in Sweden- which has the highest 3G coverage in Europe. Comparable to fixed broadband access, using a 3G USB modem is a wonderful experience for the customer. Increasingly, anywhere we can use our cellular phone is a place that we are able to access the Internet, even if we are traveling in a train, walking in a park, or sitting on the beach. This makes working on the move much easier. However, customers do not know if the network throughput, delay, and the cost of connectivity match their needs. Additionally, there is also the question of the time to connect to the network when there has not been some traffic for a period of time. However, the throughput, delay, and "time to connect" when using such a modem to connect to a wireless network depend on several factors. In this thesis we will examine these factors. More specifically, the thesis will analyze in detail the effects of using a USB attached network interface, in order to gain greater understanding of such an interface’s network performance. We have chosen to focus on the uplink, as it was expected to have a low throughput and it has not had as much attention as the downlink performance. / Fler och fler människor över hela världen använder ett USB-modem för att ansluta tillInternet. Detta gäller i synnerhet i Sverige, som har den största 3G-täckning i Europa.Jämförbar med fast bredband, med hjälp av ett 3G USB-modemet är en underbar upplevelseför kunden. Allt var som helst vi kan använda vår mobiltelefon är en plats som vi hartillgång till Internet, även om vi färdas i ett tåg, promenad i en park, eller sitter på stranden.Detta gör att arbeta på resande fot mycket enklare. Men kunderna inte vet om nätetgenomströmning, fördröjning, och kostnaden för anslutning passar deras behov. Dessutomfinns det också en fråga om tid att ansluta till nätverket när det inte har funnits några trafikför en tid. Men den genomströmning, fördröjning och "tid för att ansluta" när du använderett modem för att ansluta till ett trådlöst nätverk beror på flera faktorer. I denna avhandlingkommer vi att undersöka dessa faktorer. Mer specifikt avhandlingen analyserar i detaljeffekterna av att använda en USB bifogade nätverkskort, för att få större förståelse för ettsådant gränssnitt nätverk prestanda. Vi har valt att fokusera på upplänk, eftersom detförväntas ha låg kapacitet och det har inte fått lika mycket uppmärksamhet som denerlänkning prestanda.

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