• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 401
  • 164
  • 77
  • 70
  • 47
  • 46
  • 15
  • 14
  • 5
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 995
  • 339
  • 174
  • 165
  • 151
  • 149
  • 143
  • 116
  • 114
  • 106
  • 103
  • 91
  • 87
  • 86
  • 85
  • 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.
141

Broadband RF Front-End Design for Multi-Standard Receiver with High-Linearity and Low-Noise Techniques

Kim, Ju Sung 2011 December 1900 (has links)
Future wireless communication devices must support multiple standards and features on a single-chip. The trend towards software-defined radio requires flexible and efficient RF building blocks which justifies the adoption of broadband receiver front-ends in modern and future communication systems. The broadband receiver front-end significantly reduces cost, area, pins, and power, and can process several signal channels simultaneously. This research is mainly focused on the analysis and realization of the broadband receiver architecture and its various building blocks (LNA, Active Balun-LNA, Mixer, and trans-impedance amplifier) for multi-standard applications. In the design of the mobile DTV tuner, a direct-conversion receiver architecture is adopted achieving low power, low cost, and high dynamic-range for DVB-H standard. The tuner integrates a single-ended RF variable gain amplifier (RFVGA), a current-mode passive mixer, and a combination of continuous and discrete-time baseband filter with built-in anti-aliasing. The proposed RFVGA achieves high dynamic-range and gain-insensitive input impedance matching performance. The current-mode passive mixer achieves high gain, low noise, and high linearity with low power supplies. A wideband common-gate LNA is presented that overcomes the fundamental trade-off between power and noise match without compromising its stability. The proposed architecture can achieve the minimum noise figure over the previously reported feedback amplifiers in common-gate configuration. The proposed architecture achieves broadband impedance matching, low noise, large gain, enhanced linearity, and wide bandwidth concurrently by employing an efficient and reliable dual negative-feedback. For the wideband Inductorless Balun-LNA, active single-to-differential architecture has been proposed without using any passive inductor on-chip which occupies a lot of silicon area. The proposed Balun-LNA features lower power, wider bandwidth, and better gain and phase balance than previously reported architectures of the same kind. A surface acoustic wave (SAW)-less direct conversion receiver targeted for multistandard applications is proposed and fabricated with TSMC 0.13?m complementary metal-oxide-semiconductor (CMOS) technology. The target is to design a wideband SAW-less direct coversion receiver with a single low noise transconductor and current-mode passive mixer with trans-impedance amplifier utilizing feed-forward compensation. The innovations in the circuit and architecture improves the receiver dynamic range enabling highly linear direct-conversion CMOS front-end for a multi-standard receiver.
142

Automatizované pracoviště pro měření parametrů zesilovačů / Automated workplace for amplifier parameters measurement

Jurčík, Petr January 2011 (has links)
The aim of this work is to create an automated workplace for measuring the basic parameters of audio amplifiers using a graphical programming environment LabVIEW. Subsequently, the functionality will be verified in practical measurements on the real amplifier.
143

Implementing a receiver in a fast data transfer system : A feasibility study

Hall, Filip, Håkansson, Pär January 2003 (has links)
<p>This report is an outcome of a master degree project at Linköpings University in co-operation with Micronic Laser Systems AB. </p><p>The purpose with this master degree project was to investigate how to implement a receiver in a data transfer system. The system consists of several data channels, where every channel consists of three parts: driver, transmission lines and receiver. The driver send low amplitude differential signals via the transmission lines to the receiver that amplifies and converts it to a single-ended signal. The receiver has to be fast and be able to feed an output signal with high voltage swing. It is also needed for the receivers to have low power consumption since they are close to the load, which is sensitive to heat. </p><p>Different amplifier architectures were investigated to find a suitable circuit for the given prerequisites. In this report the advantages and disadvantages of voltage and current feedback are discussed. </p><p>The conclusions of this work are that in a system with an amplifier as a receiver with differential transmission lines, a single operational amplifier cannot be used. An input stage is needed to isolate the feedback net from the inputs of the operational amplifier. When fast rise time and large output swing are wanted the best amplifier architecture is current feedback amplifiers. A current feedback amplifier in CMOS with the required high voltages and slew rate is hard to realize without very high power consumption.</p>
144

Implementing a receiver in a fast data transfer system : A feasibility study

Hall, Filip, Håkansson, Pär January 2003 (has links)
This report is an outcome of a master degree project at Linköpings University in co-operation with Micronic Laser Systems AB. The purpose with this master degree project was to investigate how to implement a receiver in a data transfer system. The system consists of several data channels, where every channel consists of three parts: driver, transmission lines and receiver. The driver send low amplitude differential signals via the transmission lines to the receiver that amplifies and converts it to a single-ended signal. The receiver has to be fast and be able to feed an output signal with high voltage swing. It is also needed for the receivers to have low power consumption since they are close to the load, which is sensitive to heat. Different amplifier architectures were investigated to find a suitable circuit for the given prerequisites. In this report the advantages and disadvantages of voltage and current feedback are discussed. The conclusions of this work are that in a system with an amplifier as a receiver with differential transmission lines, a single operational amplifier cannot be used. An input stage is needed to isolate the feedback net from the inputs of the operational amplifier. When fast rise time and large output swing are wanted the best amplifier architecture is current feedback amplifiers. A current feedback amplifier in CMOS with the required high voltages and slew rate is hard to realize without very high power consumption.
145

Oscillateur de puissance en ondes millimétriques

Dréan, Sophie 19 December 2012 (has links)
Ce travail porte sur l'étude d'un oscillateur de puissance contrôlé en tension en ondes millimétriques. L'objectif de la thèse est de concevoir cet oscillateur pour la bande de fréquence utilisée dans les standards IEEE 802.15.3c, IEEE 802.11ad et ECMA TC48, à savoir 56GHz-65GHz. Le principe de l'oscillateur de puissance est développé autour d'un amplificateur de puissance rebouclé pour engendrer un système oscillant. L'amplificateur de puissance développé est un amplicateur à deux étages. Celui de puissance est de classe E et le driver est de classe F. La boucle de retour est basée sur un vecteur-modulateur. Les circuits ont été fabriqués en technologie CMOS 65nm de STMicroelectronics. / This PhD thesis deals with a Power Voltage Controlled Oscillator (VCO) in millimeter waves. The aim is to design this Power VCO in the frequency band used in the standards IEEE 802.15.3c, IEEE 802.11ad and ECMA TC48, meaning from 56GHz to 65GHz. The principle of this oscillator is developed around a power amplifier in a loop, generating an oscillating system. The power amplifier is developed in a two-stage topology. The power stage is composed with a 60GHz class E cascoded amplifier and the driver stage is composed of a 60GHz class F amplifier. The feedback of the loop is based on a vector-modulator. The circuits have been realised in 65nm CMOS technology from STMicroelectronics.
146

Výkonový zesilovač pro pásmo krátkých vln / Shortwave power amplifier

Kufa, Jan January 2014 (has links)
The aim of the master´s thesis is to create a high-frequency amplifier with switching power amplifier classes among classes A, B, C with output power of 10 W. The amplifier operates at frequency from 3.5 MHz to 14 MHz. Master´s thesis includes also theoretical analysis, design of lowpass filter and amplifiers and their simulation, mechanical realization and measured parameters of the amplifier.
147

Integrating a Limiter/Filter/Amplifier into a Conformal Wraparound GPS/TM Antenna Substrate

Ryken, Marv, Davis, Rick, Kujiraoka, Scott 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / Missile instrumentation systems designers are constantly striving to achieve better performance out of their systems. Optimizing the antenna coverage and decreasing the noise figure are constantly strived for in order to improve system performance. At the same time, weapon systems are becoming smaller with the resulting reduced area for instrumentation. One way to achieve a lower system noise figure is to have the limiter, filter, and amplifier (LFA) located as close to the antenna as possible. This can be achieved by integrating the LFA into the substrate of a conformal wraparound antenna. Not only does this decrease the system noise, but it also saves space in an already crowded missile instrumentation section. This paper details the latest efforts in accomplishing this integration.
148

ADVANCEMENTS IN TRANSMITTER HARDWARE FOR WIRELESS TELEMETRY ENGINEERS

Burke, Larry, Osgood, Karina, Muir, John, Dearstine, Christina, Cardullo, Micheal, Fox, Timothy 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / M/A-COM has developed a chip set designed specifically for miniaturized ballistic telemetry applications. One key component of this chip set is a dual port voltage controlled oscillator (VCO). This device allows for independent optimization of both modulation and tuning parameters at the chip level. In the dual port architecture, the modulation port of the VCO may be tailored for the peak (frequency) deviation requirements of each system, while still permitting the device to tune over entire SLOWER band. Additionally, M/A-COM has developed S band power amplifiers (PAs) for medium power (500mW, 1W and 2W) telemetry applications. These new PAs are very efficient, (>45% PAE) when operated in saturation. This improved efficiency means these components may be integrated into transmitters with a miniaturized form factor. The excellent thermal performance of these new PAs allows them to be packaged in commercial plastic packages which are robust in high shock/high vibration applications. This paper reviews the design of each MMIC device and presents system performance data.
149

FQPSK: A BANDWIDTH AND RF POWER EFFICIENT TECHNOLOGY FOR TELEMETRY APPLICATIONS

Gao, Wei, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A simple, low cost radio frequency (RF) power and spectrally efficient integrated transceiver/modem architecture employing Feher’s patented Quadrature Phase Shift Keying (FQPSK) is described. The FQPSK signals presented in this paper are obtained by using additional post low-pass filters in the FQPSK architecture. This implementation significantly improves the spectral efficiency of the worldwide commercially standardized Gaussian Minimum Shift Keying (GMSK) systems. The Bit Error Rate (BER) performance of FQPSK in additive white Gaussian noise (AWGN) channel has been investigated by means of computer simulation and hardware prototype measurements. The results of the hardware and software simulations are compared to GMSK and QPSK/OQPSK performance. These results show that the filtered FQPSK modulated signal passing through a non-linear amplifier (NLA) can achieve a spectral efficiency improvement of about 60% over NLA filtered OQPSK and an integrated spectral efficiency improvement of 50% over GMSK and a better BER performance. In particular, 100 kb/s to 34 Mb/s hardware experimental results over 2.4 GHz NLA (saturated) 1 Watt system confirmed that FQPSK hardware systems attain a BER=f(Eb/N0) performance within 1 dB to 2 dB of predicted theoretical results.
150

DESIGN OF A GPS/TELEMETRY ANTENNA FOR SMALL DIAMETER PROJECTILES

Ryken, Marv, Davis, Rick, Kujiraoka, Scott R. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / In the past, airplanes, target drones, pods, and large missiles have been instrumented with telemetry, flight termination and beacon tracking antennas to assess performance. With the emerging use of the Global Positioning System (GPS) for tracking purposes, GPS is also included as part of the instrumentation package. This paper addresses the design of a conformal wraparound antenna system to cover the telemetry and GPS L1 frequencies for a small (2.75 inch) diameter airborne projectile. A filter is also integrated into the antenna system to isolate the transmitted telemetry signal from the received GPS signal. This integration is necessary due to the lack of space in the small diameter projectile. Performance characteristics of the prototype antenna system are also presented.

Page generated in 0.0268 seconds