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301 Uppsatser om Noise burst - Sida 2 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.

Taluppfattningstest med enstaviga ord i brus: Normalvärden för barn i åldrarna 7, 10 och 13 år

Background: Phonemically balanced word lists are used when obtaining speech recognition scores in noise. These lists are designed for adults, but are still used for children. To properly obtain speech recognition scores in noise for children, normative data is needed to show what differences there are to be expected between children of different ages. Purpose: The main purpose is to obtain normative data for children in the ages of 7, 10 and 13 years for speech recognition scores in noise using words and to compare these with each other and with normative data of adults. A further purpose is to examine if there is any practice- or exhaustion effect to be seen when obtaining speech recognition scores in noise for children in the ages of 7, 10 and 13 years.Material: The participants were ten 7-year-olds, ten 10-year-olds and ten 13-year-olds.

Korrelerar startlereaktion med reaktionstid?

Bilder av potentiella hot upptäcks snabbt och leder till en snabbare reaktionstid än bilder av icke-potentiella hot. Potentiella hot stjäl också fokus och kognitiva resurser, med en långsammare reaktionstid som följd. Rädsla, som kan mätas genom startlereflexen, leder till antingen ökad handlingsberedskap (snabbare reaktionstid) eller kognitiv distraktion (långsammare reaktionstid). Fem försöksdeltagare fick reagera på en visuell probe som lades ovanpå djurbilder, både potentiella hot och icke-potentiella hot i ett kombinerat reaktionstids- och startleprobeexperiment, där ljudstötar utdelades i hörlurar. Startlereaktion, hjärtfrekvens och reaktionstid mättes, varefter korrelationskoefficienter räknades ut.

Korrelerar startlereaktion med reaktionstid?

Bilder av potentiella hot upptäcks snabbt och leder till en snabbare reaktionstid än bilder av icke-potentiella hot. Potentiella hot stjäl också fokus och kognitiva resurser, med en långsammare reaktionstid som följd. Rädsla, som kan mätas genom startlereflexen, leder till antingen ökad handlingsberedskap (snabbare reaktionstid) eller kognitiv distraktion (långsammare reaktionstid). Fem försöksdeltagare fick reagera på en visuell probe som lades ovanpå djurbilder, både potentiella hot och icke-potentiella hot i ett kombinerat reaktionstids- och startleprobeexperiment, där ljudstötar utdelades i hörlurar. Startlereaktion, hjärtfrekvens och reaktionstid mättes, varefter korrelationskoefficienter räknades ut.

Värdet av tystnad : en värderingsstudie över Upplands Väsbybornas betalningsvilja för reducerat flygbuller

Since the spring 2003 the tenant-owner home association the Terrace in Upplands Väsby municipality lies straight under the approach route to Arlanda Airport?s new third landing chute. Noise levels of over 70 dB have been measured in the area, which exceeds National Board of Housing?s, values for traffic noise at a terrace in connection to housing. By using the method of hedonisk pricing the essay tries to find out if there exists a willingness to pay to reduce the noise in the area.

Dämpning av ljud i Shift-by-Wire växelväljare : Noise damping in a Shift-by-Wire gear shifter

Constantly growing demands from the costumers in the Automotive industry forces the subcontractors to seek alternative ways to compete. One parameter of quality is the components tolerance against NVH(Noise, Vibraion & Harshness) aspects. Kongsbergs Automotive has developed a new gear shifter platform (Shift-by-Wire) that is sold to Alfa Romeo and used in of their car models. However, the company is not pleased with the components sound quality, therefore the main purpose of this thesis is to develope a number of concepts that is supposed to enhance these NVH-aspects.To get an understanding of the problem an analysis of the causes of the emitted sound has been done parallell to a product decomposition, function decomposition and a Ishikawa-diagram. Together with these methods has a litterature study been performed to get familiar with the physics of an impact and especially the emittment of noise.

Strömkontroll till aktiva magnetlager med noggrann och störningsreducerad strömmätning

There is always a need for more effective ways to store energy in order to reduce the human impact on the environment. One step on the way can be the use of flywheels as kinetic energy storage devices. Low frictional losses are essential for a flywheel to be effective. To minimize these losses active magnetic bearings (AMB) can be used to keep the shaft centered instead of the more conventional ball-bearings. AMBs use actuators and a fast control system that needs correct and noise-free measurement data of the shaft position and the current in the actuators to work properly.This thesis explains the process of constructing power electronics and a current measurement system for active magnetic bearings (AMB).

VÄGTRAFIKBULLRETS INVERKAN PÅ UTFORMNINGEN AV BOSTADSBYGGNADER I STADSMILJÖ

The public interest in central living in today?s cities has led to an increasing effect of traffic noise pollution, and today 20% of the inhabitants in Sweden suffer from noise a level that exceeds the limits. At the same time the traffic keeps increasing, and recent researches shows that traffic noise pollution and several of today?s most common health issues are connected, for example, reduction of performance, sleeping issues and cardiovascular diseases. For this cause rules, guidelines and environmental goals has been developed, as well as software?s which calculates the levels of pollution, all this to investigate and improve the environment.

Bil- och järnvägstrafikens inverkan på inomhusmiljön med avseende på ljud och luft : - I planerade bostäder på Haga

NCC has given us a commission to investigate a planned housing area in Haga, Karlstad, situated close to the traffic route Hagaleden and the railway. The housing area consists of one hundred apartments in five different houses. The houses are linked to each other by balconies with glass panels. A long carport is situated between Hagaleden and the housing area to absorb part of the noise from the road. The design of the housing area is creating a silent backyard.

Bilar eller blåmesar? : rehabiliteringsvärdet i Umeås tätortsnära skogar

Nature´s healing capacity is well known and is today an important asset in the protection against stress. Noise problems in cities and it´s green spaces are increasing which in turn provokes stress and in the long term can lead to cardiovascular diseases. To promote people?s health it is important that natural environments have good soundscapes, research show that visiting natural surroundings and listening to sounds of nature promote rehabilitation and relief stress. The purpose of this essay is to determine the value of rehabilitation in forests in Carlshem and Röbäck.

Läsflöde eller läsmöda? : Ett arbete om hur la?sning pa?verkas (och inte pa?verkas) av olika element pa? en webbplats fo?rstasida.

The purpose of this project was to find out how reading is affected, and not affected, by different elements on a start page. The site I was studied belongs to the magazine Fitness Magazine, and the current site has a problem. The editorial texts and articles don?t reach out to the visitors. The goal was to make a proposal for a new first page of the web site that highlights the texts and the reading.With the help of interviews, user testing and textual analysis, I studied if the texts were in itself that caused the problem or if it was the design.

Ljud eller oljud? : planering av goda ljudmiljöer

In our everyday life we are constantly affected by sound; at home, on our way to and from work, when taking a walk through the woods and when we sleep. In discussions about sound one often talk about noise and to what degree a certain noise disturbs us. The positive qualities of a sound and what sounds contribute to the experience of a good environment is rarely discussed. The question of sound and the quality of sound is given more attention through the expansion of Stockholm, the city is becoming both bigger and more crowded. This raises new questions concerning the planning of the city e.g. should the changes of the sound quality in a place be one of the aspects taken into consideration when planning new buildings, are there ways to improve the sound quality in new building projects? Can we even improve the quality of sound in existing places by simple means? I have chosen to study four different areas in Stockholm; Hötorget, Mariatorget, Berzeliipark and Norrmalmstorg.

Filter och kapsling för IR-givare

This paper describes the work done trying to diminish the noise present in the signal from an IR-detector. The project was aiming towards two different kinds of applications; heat protection and presence detection. The hypothesis was that the signal-noise ratio would decrease if a filter and a proper installation were used for the detector. Some experiments were executed to determine what kind of filter were the most suitable for each application and how these could be installed. After executing the experiments and evaluate the results we recommend to use a specific filter for each application.

Riskerar tatuerare hörselnedsättning i arbetet?

Purpose: To examine the hearing environment for tattoo artists regarding occupational noiseand to see whether tattoo artists are exposed to hazardous noise according to Swedish WorkEnvironment Authority regulations. Method: Using a dosimeter we measured a total ofseven sessions of approximately one hour on seven different subjects, located on five studiosin Gothenburg. As a complement we did also hand out surveys based on twelve questions toexamine habits, experienced sound environment and to see if there were any hearing relatedpatterns. Results:. Sound level measurements showed that the lower exposure action valueLpAeq,8h 80 dB(A) in one case was reached if applied to the average working time of sixhours.

Hörapparatnyttan hos dem som ordinerats hörapparat med öppen anpassning ? En utvärdering

An open fitting is suitable for persons with sloping hearing loss and relatively good low fre-quency hearing. Sensory neural hearing losses often have this type of configuration. A large ventilation canal gives a greater feeling of comfort and less occlusion. The purpose of this study was to look at the hearing aid benefit of open fitted hearing aids. Self report question-naires were sent out to 102 patients who were given ReSound AIR during the year of 2006 in Uddevalla.

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