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310 Uppsatser om Low-noise amplifier - Sida 1 av 21

Design of a Direct-conversion Radio Receiver Front-end in CMOS Technology

In this Master's thesis, a direct-conversion receiver front-end has been designed in a 0.18um CMOS technology. Direct-conversion receivers (DCR) have obvious advantages over the heterodyne counterpart. Since the intermediate frequency (IF) is zero, the problem of image is circumvented. As a result, no front-end image reject filter is required and the channel selection requires only a low-pass filter, which makes it easy to integrate directly on chip. However, the DCR also suffers from several drawbacks such as extreme sensitivity to DC offsets, 1/f noise, local oscillator (LO) leakage/radiation, front-end nonlinearity and I/Q mismatch.

Drivförstärkare : Bredbandig drivförstärkare med hög verkningsgrad

This report present the design and manufacturing of a wide-band driver amplifier placed in radar module for airborne applications. The major goals for the amplifier were a high efficiency and to deliver a predefined output power. To reach the second goal an additional preamplifier had to be constructed. The amplifiers were constructed in three steps: Design and Layout in the software Microwave Office, Mounting components and Verification. The driver amplifier was decided to be a push pull configuration consisting of two parallel transistors biased in class AB.

Design av slutsteg med digital PWM-teknik för gitarr

Softube has developed DSP-card and software for simulation of the sound of old tube amplifiers. The purpose with this thesis is to design a compact amplifier with high power to function together with the DSP-card and build a unit that can replace several other guitar amplifiers. The advantages with that kind of solution could be that it would be cheaper, easier to carry and easier to stor than the real amplifiers. The amplifier that has been designed is of class D type with digital PWM modulator. There is several types of amplifier modules on the market that use analog input signal, but if one of them would be used a D-A converter is needed on the DSP card.

PWM Effekt Audioförstärkare

The purpose with the report is to show that it is possible to design a class-D amplifier, using a programmable FPGA mounted on a developing card from Xess and a H-bridge. The FPGA was programmed in VHDL which is the language the software from Xilinx use to implement a logical function into the FPGA The logical function corresponds to a modeling of the music signal and the modeling can be described as a comparator which compare the music signal with a triangle wave and as a out signal produce a pulse width modulated (PWM) signal. The report is also a review and evaluating of two different modulating technologies, AD- modeling and BD-modeling. A detailed part about how the H-bridge was designed and how it works. The result of this project is a working audio amplifier to a significant lower price than the products in todays market..

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

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.

NOISE OCH MINNE

Detta arbete handlar om noise och hur det påverkar människans arbetsminne. Den litterära bakgrunden presenterar vad noise är, hur noise fungerar som musik samt en generell överblick över minne och arbetsminnet. Problemet som undersöktes var om noise kunde påverka förmågan att tillgodogöra sig visuell information mer än vad vitt brus gjorde. För att få ett svar på frågan skapades två versioner av ett enkelt spelmoment där testpersonerna, indelade i två grupper, fick se en siffersekvens som sedan skulle skrivas ner. Samtidigt spelades i spelmomentet antingen noise eller vitt brus upp.

Åtgärder för att minimera trafikbullers påverkan på ett rekreationsområde

The aim of this inquiry was to investigate the most appropriate measures to reduce noise impacts from road traffic on the Nydala recreational area in Umeå municipality due to the planned re-routing of the E4 motorway to an existing road along this area. The sound environment is an important part in the experience when we are visiting recreational areas. Noise is not only disturbing; the liberty from unwanted sounds also allows us to perceive natural sounds that are a benefit for the cultural experience. Therefore it is important to take actions to protect this well used area from traffic noise. The reasonable options to avoid noise impact in this case are to lower the speed limit, using a noise reducing coating or use noise protection screens and walls.

Bullertunneln : En utredning kring en ny bullerlösning vid trafikleder

The purpose of this Master Thesis has been to investigate the possibilities for a new type of noise reduction solution that could decrease the negative effects resulting from larger traffic roads. The idea has been to construct a noise barrier with a roof ? like a tunnel placed on a road. The choice of material has been focused on transparent materials in order to lower visual intrusion and barrier effects. This project idea is called the Noise tunnel.After having investigated the current offer of noise solutions, it has been concluded that these solutions rarely provide a sufficient level of noise reduction ? at least not when government regulations of acceptable noise levels are applied.

Buller : Hur planeras en bullerfri stad?

Milosevic, S. 2014. Buller ? Hur planers en bullerfri stad?. Kulturgeografiska institutionen, Uppsatser, Uppsala universitet. This essay is about noise pollution caused by urbanization.

Automatiserad konstruktion av analoga förstärkare

The last few decades the development in the field of electronics has been huge. The components performance gets better at the same time as the manufacturing cost decreases. Many of the design moments that have to be done, are done automatically today, but it can get better. Especially for analog circuit design.At Electronic System in Linköpings universitet, research is in progress to develop a tool that can design analog circuits in reasonable time. It means that it has to size the components (transistors, resistances, capacitances etc), so that the circuit can fulfill the performance requirements.

Bakgrundsbrusets effekt på kognitiv prestation samt skapandet av falska minnen : Om bullrets inverkan i öppna kontorsmiljöer

This study aimed to explore how 31 collage students' cognitive performance and their ability to create false memories were affected by the exposure of an extraneous background noise. The studies main hypotheses were based on previous research on how extraneous noise affect the cognitive ability and the creation of false memories: 1) that an extraneous background noise increases the ability to create false memories, 2) that an extraneous background noise impairs the learning of cognitive information, 3) that an extraneous background noise contributes to an increased representation of fictional words, 4) that an extraneous background noise impedes the ability to understand speech . The results showed a tendency in which false memories increased in the condition without background noise, a result which goes in the opposite direction of the hypothesis. Furthermore, the result supported the hypothesis that the extraneous background noise impairs the learning of cognitive information. The results also showed that there was no effect between the conditions regarding the representation of fictional information.

Oljudens musik : En revolution i kompositionsteknik?

Noise music is created around sounds not often welcome in a musical context. Since the birth of electronic music in the 1950s a new perspective on composing has emerged. In electronic music, sounds and their timbre are as much important as melody, harmony and rhythm. This composing perspective is not often observed. Therefore I have examined a musical genre that stretches the boundaries of what we consider music, sound, noise, beautiful and terrible.

Trådlös energiöverföring via elektromagnetisk induktion

This paper describes a method for wireless energy transfer via near-field electromagnetic inductionthat is inexpensive, simple and can be applied to almost any type of system, regardless of size andenergy demands.The method uses a primary unit consisting of an oscillator, amplifier and inductive coil thattransfers energy to a secondary unit consisting of a coil, rectifier and voltage regulator. Two typesof oscillators and several amplifier designs were realized and evaluated together with a multitudeof flat coils of both monofilar and bifilar type.The results show that it is important to use an oscillator whose frequency is dependent on theinductance of the connected transmission coil, such as the Colpitts oscillator. This is preferable toan oscillator with a preset frequency, such as a Schmitt-trigger oscillator..

Skalning och brusberäkning av tvåportsadaptorer

The goal of this work is to summarize the calculations for scaling and noise of twoportadaptor. Two different methods has been described and used for the final results..

Aktiv bullerdämpning i ventilationssystem

Active headsets have been on the market for years and now it is time for something else to enter the stage. The technology of active noise reduction can for exmple also be used in ventilation systems for reducing ventilation noise. An active control system principally consists of four important components, namely the downstream error microphone, the upstream detection or reference microphone, the digital signal processor (DSP) and a loudspeaker. The upstream reference microphone listen to the primary ventilation noise and sends it to the DSP which makes a phase shift to the signal and sends it to the loudspeaker. The loudspeaker sends out the opposite waveform of the incoming one and reduce the primary ventilation noise.

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