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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.
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Showing 1 to 9 of 9 (0.041 seconds)| 1 |
Performance Evaluation of Raised-Cosine Wavelet for Multicarrier ApplicationsAnoh, Kelvin O.O., Abd-Alhameed, Raed, Ochonogor, O., Dama, Yousef A.S., Jones, Steven M.R., Mapoka, Trust T. 30 September 2014 (has links)
Yes / Wavelets are alternative building kernels of the multicarrier systems, such as the orthogonal frequency division
multiplexing (OFDM). The wavelets can be designed by changing the parent basis functions or constructing new filters.
Some two new wavelets are considered for multicarrier design; one is designed using raised-cosine functions while the other was constructed using ideal filters. The spectrums of raised cosine wavelet filters are controlled by a roll-off factor which leads to many distorting sidelobes. The second family of wavelet, which the raised-cosine wavelet is compared to, have no distorting sidelobes. It will be shown that raised-cosine wavelets are less suitable for multicarrier design in
multicarrier environment, in terms of BER when compared to the wavelet constructed from the ideal filter.
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On the application of raised-cosine wavelets for multicarrier systems designAnoh, Kelvin O.O., Mapoka, Trust T., Abd-Alhameed, Raed, Ochonogor, O., Jones, Steven M.R. 08 1900 (has links)
Yes / New orthogonal wavelet transforms can be designed by changing the wavelet basis functions or by constructing new low-pass filters (LPF). One family of wavelet may appeal, in use, to a particular application than another. In this study, the wavelet transform based on raisedcosine spectrum is used as an independent orthogonal wavelet to study multicarrier modulation behaviour over multipath channel environment. Then, the raised-cosine wavelet is compared with other well-known orthogonal wavelets that are used, also, to build multicarrier modulation systems. Traditional orthogonal wavelets do not have side-lobes, while the raised-cosine wavelets have lots of side-lobes; these characteristics influence the wavelet behaviour. It will be shown that the raised-cosine wavelet transform, as an orthogonal wavelet, does not support the design of multicarrier application well like the existing well-known orthogonal wavelets.
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SPECTRAL EFFICIENCY OF 8-ARY PSK MODULATION UTILIZING SQUARE ROOT RAISED COSINE FILTERINGScheidt, Kelly J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / As frequency allocation restrictions are tightening, and data rates are increasing, it is becoming
necessary to incorporate higher order modulation techniques to make more efficient use of available
spectrum. When used with Square Root Raised Cosine filtering, 8-ary Phase Shift Keyed
modulation is a spectrally efficient technique that makes better use of today’s RF spectrum in
comparison to standard formats. This paper will discuss 8-ary PSK modulation and its spectral
efficiency with a SRRC filter, along with comparisons to BPSK, QPSK, and FSK.
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Digital implementation of high speed pulse shaping filters and address based serial peripheral interface designRachamadugu, Arun 19 November 2008 (has links)
A method to implement high-speed pulse shaping filters has been discussed. This technique uses a unique look up table based architecture implemented in 90nm CMOS using a standard cell based ASIC flow. This method enables the implementation of pulse shaping filters for multi-giga bit per second data transmission. In this work a raised cosine FIR filter operating at 4 GHz has been designed. Various Implementation issues and solutions encountered during the synthesis and layout stages have been discussed.
In the second portion of this work, the design of a unique address based serial peripheral interface (SPI) for initializing, calibrating and controlling various blocks in a large system has been discussed. Some modifications have been made to the standard four-wire SPI protocol to enable high control speeds with lesser number of top-level pads. This interface has been designed to function in the duplex mode to do both read and write operations.
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Performance Evaluation of Raised-Cosine Wavelet for Multicarrier ApplicationsAnoh, Kelvin O.O., Abd-Alhameed, Raed, Ochonogor, O., Dama, Yousef A.S., Jones, Steven M.R., Mapoka, Trust T. January 2014 (has links)
No / Wavelets are alternative building kernels of the
multicarrier systems, such as the orthogonal frequency division
multiplexing (OFDM). The wavelets can be designed by
changing the parent basis functions or constructing new filters.
Some two new wavelets are considered for multicarrier design;
one is designed using raised-cosine functions while the other
was constructed using ideal filters. The spectrums of raisedcosine
wavelet filters are controlled by a roll-off factor which
leads to many distorting sidelobes. The second family of
wavelet, which the raised-cosine wavelet is compared to, have
no distorting sidelobes. It will be shown that raised-cosine
wavelets are less suitable for multicarrier design in
multicarrier environment, in terms of BER when compared to
the wavelet constructed from the ideal filter.
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BANDWIDTH LIMITED 320 MBPS TRANSMITTERAnderson, Christopher 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / With every new spacecraft that is designed comes a greater density of information that will
be stored once it is in operation. This, coupled with the desire to reduce the number of
ground stations needed to download this information from the spacecraft, places new
requirements on telemetry transmitters. These new transmitters must be capable of data
rates of 320 Mbps and beyond.
Although the necessary bandwidth is available for some non-bandwidth-limited
transmissions in Ka-Band and above, many systems will continue to rely on more narrow
allocations down to X-Band. These systems will require filtering of the modulation to meet
spectral limits. The usual requirements of this filtering also include that it not introduce
high levels of inter-symbol interference (ISI) to the transmission.
These constraints have been addressed at CE by implementing a DSP technique that pre-filters
a QPSK symbol set to achieve bandwidth-limited 320 Mbps operation. This
implementation operates within the speed range of the radiation-hardened digital
technologies that are currently available and consumes less power than the traditional high-speed
FIR techniques.
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An FPGA implementation of a modulator for digital terrestrial television according to the DTMB standard / FPGA-implementation av en modulator för marksänd digital television enligt DTMB-standardenAbrahamsson, Sebastian, Råbe, Markus January 2010 (has links)
<p>The increasing data rates in digital television networks increase the demands on data capacity of the current transmission channels. Through new standards, the capacity of exisiting channels is increased with new methods of error correction coding and modulation.</p><p>This thesis presents the design and implementation of a modulator for transmission of digital terrestrial television according to the Chinese DTMB standard.</p><p>The system is written in VHDL and is intended for implementation on an FPGA.</p>
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An FPGA implementation of a modulator for digital terrestrial television according to the DTMB standard / FPGA-implementation av en modulator för marksänd digital television enligt DTMB-standardenAbrahamsson, Sebastian, Råbe, Markus January 2010 (has links)
The increasing data rates in digital television networks increase the demands on data capacity of the current transmission channels. Through new standards, the capacity of exisiting channels is increased with new methods of error correction coding and modulation. This thesis presents the design and implementation of a modulator for transmission of digital terrestrial television according to the Chinese DTMB standard. The system is written in VHDL and is intended for implementation on an FPGA.
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Mikrovlnné modulátory na bázi sixportů / Microwave Modulators Based on SixportsDušek, Martin January 2018 (has links)
This doctoral thesis is focused on problems of modulators based on six-ports. It begins with description of current state of the art of six-ports used like modulators, their transfer functions and SIW technology. A design part of this thesis consists from experimental six-port based on substrate integrated waveguide (SIW) technology. There is presented step-by-step development of this six-port using this technology and also there is introduced micro-strip technology based six-port. Final design of six-ports and variable impedances were measured, the results are discussed and compared with expected ones in next chapters. Second part of this thesis deals with influences of internal parameters of six-ports to final signal transmission and derives theirs transfer functions for more than one reflection in structure. The computation results are compared with experimental measurements for fixed loads. With using of ideal loads sweeps, modulations with shaped input signals were calculated. For designed variables impedances, there was founded the optimal biasing points for demanded IQ diagram and discussed which from tested active circuit is suitable. In the last part there are shown results of experiment with these variable loads connected to both types of designed six-ports.
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