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  • 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.
1

Digital videoregistrering

Eliasson, Viktor January 2013 (has links)
This Bachelor thesis examines the possibility of replacing an outdated, analog video recording system to a digital counterpart. It is key that the video and audio signals remain synchronized, generator locked and time stamped. It is up to nine different video sources and a number of audio sources to be recorded and treated in such a manner which enables synchronized playback. The  different video sources do not always follow a universal standard, and differ from format as well as resolution. This thesis aims to compare a number of state of the art commercial of the shelf solutions with proprietary hardware. Great emphasis is placed on giving a functional view over the system features and to evaluate different compression methods. The report also discusses different transmission, storage and playback options. The report culminates in a series of proposed solutions to sub problems which are solved and treated separately, leading to a final proposal from the author. The final draft set how well the system meets pre-set requirements to price.
2

Live Demonstration of Mismatch Compensation for Time-Interleaved ADCs

Nilsson, Johan, Rothin, Mikael January 2012 (has links)
The purpose of this thesis is to demonstrate the effects of mismatch errors that occur in time-interleaved analog-to-digital converters (TI-ADC) and how these are compensated for by proprietary methods from Signal Processing Devices Sweden AB. This will be demonstrated by two different implementations, both based on the combined digitizer/generator SDR14. These demonstrations shall be done in a way that is easy to grasp for people with limited knowledge in signal processing. The first implementation is an analog video demo where an analog video signal is sampled by such an TI-ADC in the SDR14, and then converted back to analog and displayed with the help of a TV tuner. The mismatch compensation can be turned on and off and the difference on the resulting video image is clearly visible. The second implementation is a digital communication demo based on W-CDMA, implemented on the FPGA of the SDR14. Four parallel W-CDMA signals of 5 MHz are sent and received by the SDR14. QPSK, 16-QAM, and 64-QAM modulated signals were successfully sent and the mismatch effects were clearly visible in the constellation diagrams. Techniques used are, for example: root-raised cosine pulse shaping, RF modulation, carrier recovery, and timing recovery.
3

Design and Implementation of an Analog Video Signal Quality Measuring Software for Component Video / Design och implementering av utvärderingsmjukvara för signalkvalitet i analog komponentvideo

Ljungström, Carl January 2010 (has links)
An IP based set-top box (STB) is essentially a lightweight computer used to receive video over the Internet and convert it to analog or digital signals understood by the television. During this transformation from a digital image to an analog video signal many different types of distortions can occur. Some of these distortions will affect the image quality in a negative way. If these distortions could be measured they might be corrected and give the system a better image quality. This thesis is a continuation of two previous theses where a custom hardware for sampling analog component video signals was created. A software used to communicatewith the sampling hardware and perform several different measurementson the samples collected has been created in this thesis. The analog video signal quality measurement system has been compared to a similar commercial product and it was found that all except two measurement methods gave very good results. The remaining two measurement methods gave acceptable result. However the differences might be due to differences in implementation. The most important thing for the measurement system is to have consistency. If a system has consistency then any changes leading to worse videoquality can be found.

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