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9 Uppsatser om Waveform - Sida 1 av 1

Optimal bredbandig vågform framtagen genom generaliserad osäkerhetsfunktion

The Waveform of a radar signal affects the resolution in velocity and distance. The ambiguity function is used as an aid for analysing narrow band radar signals simultaneously in time and frequency. An analysing tool for wide band radar signals is missing.This thesis describes a generalised ambiguity function to be utilised for study of wide band signals. Waveforms are further synthesised with help of the developed analysing tool. The aim is to start with a certain ambiguity function and find a Waveform that reproduces the same ambiguity function.Mathematical formulas are presented and implemented in Matlab to produce the wide band ambiguity function.

Syntetiska Instrument

This thesis aims to investigate SAAB AB´s possibilities to use synthetic instruments in their test systems. The reason for this is reducing costs and the risk of obsolescence which is common when test systems operate for several decades.The market around synthetic instruments has been explored in the search for suitable hardware and software. Software has been developed in LabVIEW and synthetic instruments have been created with the help of IVI-drivers. The hardware consisted of PXI-instruments (Waveform generator and Digitizer), connected to a computer using a fiber optic link and PXI-chassi. The created instruments was then compared to common instruments used today, and the comparison turned out well.

Utvärdering av försvarsspecifika radiovågformer

To be able to evaluate different radio Waveforms in a laboratory environment FOI in Linköping has developed an experimental system for radio communication called Rasmus. The system consists of a transmitter, a channel emulator and a receiver. The transmitter modulates a digital signal to a desired analogue Waveform. The channel emulator is used to simulate a real radio channel. The channel emulator distorts the signal by splitting it up in several propagation paths.

Evaluation of the retinal ON- and OFF-responses in the dog ERG

The aim of the study was to examine the retinal ON- and OFF-pathways of the canine electroretinogram (ERG). The ON- and OFF-pathways are used to distinguish objects from their backgrounds. A dark object is discernible from a lighter background using the OFFpathway and the ON-pathway is used to descry a light object upon a darker background. This study shows that the dog ERG has both ON- and OFF-responses and that these responses can be separated by prolonging the flash duration over 50 ms. The dog OFF-response Waveform was more similar to the cat OFF-response than the human OFF-response (Frishman, 2006; Zrenner and Gouras, 1979). In this study six female three-year-old Beagle dogs were included. Both background and flash stimuli were provided by LEDs (light emitting diodes) with a wavelength of 470 nm, a wavelength that is absorbed almost as effectively by the canine M/L-cones as by the S-cones. These stimuli gave ERGs with both ON- and OFF-responses.

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.

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.

Radiolänk med GNU Radio

At the Department of Technology and Built environment at the University of Gävle there was an interest to study GNU Radio, which is an "open source radio project. The project is based on that most of the radio signal processing is made in an ordinary PC. The idea behind this degree project was that in a laptop there are several radio transmitters/receivers that takes space, generates heat and transmit in varied frequency band etcetera. All these radio transmitters/receivers could be replaced with a Software Defined Radio system. It means that one common, general radio hardware is used to different communications such as: WLAN, Bluetooth, GPRS, 3G etcetera. The Waveform is generated in the software, which makes the system very flexible.

USB lösning för Digital Telemetri Mottagare

Syncore Technologies har tagit fram en digital telemetri mottagare som använder sig av USBperiferi anordning som ska kunna etablera oavbruten kommunikation mot sin värddator.Den tidigare designen av USB applikationen till digitala mottagaren är utvecklat av ett annatföretag. Problemet med den designen är att den kan stanna av under överföringen. Ett krav förden nya designen av USB gränssnittet är att den ska kunna etablera ett konstant data flödeutan att under en längre tid stanna av mitt under överföringen. Syftet med detta arbete är attordna en stabil överföring mellan mottagare och dator. Gruppen har valt att användanuvarande kretsuppsättning och utveckla egen mjukvara.

Business Potential of Software Defined Radio Technology

The business potential of software defined radio (SDR) technology is studied by evaluating whether or not its characteristics correspond to those particular to a disruptive technology. The maturity of the SDR technology concept is illuminated by analyzing the opinions and perspectives of a selection of representatives for different stakeholders in the wireless communications market. Characteristics as, for example, the degree of consensus about the utility of SDR technology and the awareness of features and limitations are studied by application of the theory of technological frames. This theory helps us understand how and when technology evolution takes place. Finally we describe the value network structures of some potentially viable application areas for SDR and suggest some possible business opportunities based on SDR technology.This thesis is carried out as a case study and the research data is obtained from secondary sources, such as literature and Internet publications as well as interviews with people well experienced in the field of wireless communications.