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| 2. |
- Andersson, Tomas, et al.
(författare)
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Frequency estimation utilizing the Hadamard transform
- 2001
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Ingår i: 2001 IEEE WORKSHOP ON STATISTICAL SIGNAL PROCESSING PROCEEDINGS. - NEW YORK : IEEE. - 0780370112 ; , s. 409-412
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Konferensbidrag (refereegranskat)abstract
- Fast analog to digital conversion with only one bit per sample does not only make high sampling rates possible but also reduces the required hardware complexity. For short data buffers or block lengths, it has been shown that tone frequency estimators can be implemented by a simple table look-up. In this paper we present an analysis of such tables using the Hadamard transform. As an outcome of the analysis, we propose a class of nonlinear estimators of low complexity. Their performance is evaluated using numerical simulations. Comparisons are made with the proper Cramer-Rao bound and with the table look-up approach.
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| 4. |
- Lundin, Henrik, et al.
(författare)
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Analog-to-Digital Converter Error Correction using Frequency Selective Tables
- 2002
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Ingår i: RadioVetenskap och Kommunikation (RVK). ; , s. 487-490
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Error correction for analog-to-digital converters(ADCs) is considered. The frequency-dependent na-ture of ADC errors motivates the proposal of a novel scheme, incorporating look-up table correction andfast frequency estimation. The method is evaluated using experimental converter data, and the performance, measured in SFDR and SINAD, is found tobe superior to that of non frequency-dependent correction methods.
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| 5. |
- Skoglund, Tomas
(författare)
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Simulation of Liquid Food Processes in Modelica
- 2003
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Ingår i: 3rd International Modelica Conference, November 3-4, 2003, Linköping.
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Konferensbidrag (refereegranskat)abstract
- Traditionally, liquid food processing equipment has been designed and engineered from a static perspective, where it has been taken for granted that dynamic behaviour easily could be handled by “add on” of control equipment such as sensors and computers with control programs including control loops. However, as production demands, e.g. mixing accuracy, are escalated, this approach fails, and the importance of simulating the dynamics of the system becomes crucial. A tool that makes it possible to minimise the cost and time for building prototypes and making experiments would be of considerable value, particularly if the tool enables reuse of earlier work. Equally important is the possibility to test various design ideas to improve the equipment performance to en extent that otherwise would not be conceivable. This article describes how the Modelica based tool Dymola1 has been used to build up a library (“FoodProcessing”) primarily aiming at simulating certain dynamic behaviour in liquid food processing plants, particularly characterised by incompressible fluids with complex rheologic behaviour, transport delays and dynamically changing concentration
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| 6. |
- Sköllermo, Tomas, et al.
(författare)
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A subband image coder for channels with both errors and erasures
- 2003
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Ingår i: CONF REC ASILOMAR CONF SIGNAL. ; , s. 1553-1557
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Konferensbidrag (refereegranskat)abstract
- We illustrate how channel optimized vector quantization (COVQ) can be used for channels with both bit-errors and bit-erasures. The resulting performance is first evaluated for a Gaussian memoryless source. Then the usefulness of the proposed method in image transmission over channels with errors and erasures is demonstrated by implementing the new COVQ technique in a sub-band image coder.
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| 7. |
- Wernersson, Niklas, et al.
(författare)
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Improved Quantization in Multiple Description Coding by Correlating Transforms
- 2004
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Ingår i: 2004 IEEE 6th Workshop on Multimedia Signal Processing. - 0780385780 ; , s. 486-489
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Konferensbidrag (refereegranskat)abstract
- The objective with Multiple Description Coding (MDC) is to code one source of data into multiple bitstreams. The coding is done in such a way that multiple levels of quality is achieved. This means that even if one or a few of the bitstreams are lost, the received bits should make it possible to get an approximated version of the original data. One way to do this is to use pairwise correlating transforms which will introduce correlation between the bitstreams. This correlation can be used in order to get an estimate of a lost stream. In this paper a new approach for MDC using pairwise correlating transforms is presented. In this approach, contrary to previous work, quantization of the source data is performed after the data has been transformed. This makes it possible to improve the shape of the quantization cells and to tailor these to the employed transform. We demonstrate that this offers a substantial performance gain compared with previous approaches to MDC using pairwise correlating transforms.
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