Avancerad sökning

Visar resultat 1 - 5 av 16 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Towards Low-Complexity Vector Quantization

   Författare :T. Z. Shabestary; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gaussian encoder; source coding; companding; Gaussian mixture; random coding; vector quantization; spectral coding;

   Sammanfattning : This thesis is about constructing low-complexity, yet high-performance, vector quantizers (VQs) for 'real-world' sources. Knowledge concerning the source is extracted from a finite training set. In contrast with conventional VQ design procedures, we use the training set to estimate a statistical model for the source. LÄS MER

3. 2. Trellis Source Coding Methods for Low Rates and Short Blocks

   Författare :Tomas Eriksson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Elektronik och elektroteknik; Electronics and Electrical technology; systemteori; Informatik; systems theory; Informatics; image coding; tailbiting source codes; BCJR algorithm; linear congruential recursions; trellis coding; low rate quantization; rate-distortion theory; Systems engineering; computer technology; Data- och systemvetenskap; Signal processing; Signalbehandling;

   Sammanfattning : Trellis quantization is a finite state machine based method for data compression. It is mainly applied to quantizing noise-like sources. In this thesis new trellis codes suitable for low rate quantization are derived. LÄS MER

4. 3. Distribution Preserving Quantization

   Författare :Minyue Li; W. Bastiaan Kleijn; Jan Østergaard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telecommunication; Telekommunikation;

   Sammanfattning : In the lossy coding of perceptually relevant signals, such as sound and images, the ultimate goal is to achieve good perceived quality of the reconstructed signal, under a constraint on the bit-rate. Conventional methodologies focus either on a rate-distortion optimization or on the preservation of signal features. LÄS MER

5. 4. Massive Multi-Antenna Communications with Low-Resolution Data Converters

   Författare :Sven Jacobsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; orthogonal frequency-division multiplexing; channel estimation; quantization; linear precoding; convex optimization; nonlinear precoding; linear combing; hardware impairments; analog-to-digital converter; beamforming; Massive multi-user multiple-input multiple-output; digital-to-analog converter;

   Sammanfattning : Massive multi-user (MU) multiple-input multiple-output (MIMO) will be a core technology in future cellular communication systems. In massive MU-MIMO systems, the number of antennas at the base station (BS) is scaled up by several orders of magnitude compared to traditional multi-antenna systems with the goals of enabling large gains in capacity and energy efficiency. LÄS MER

7. 5. Quantization, Perception and Speech Coding

   Författare :Fredrik Nordén; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : This thesis is about compression of speech signals, a research area known as speech coding. The aim of a speech coder is to provide efficient digital representations of speech signals, required in digital transmission and storage systems. Contemporary speech coding algorithms typically separate the speech signal into sets of parameters. LÄS MER