| 1. |
- Gustafsson, Oscar, 1973-, et al.
(författare)
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Implementation of polyphase decomposed FIR filters for interpolation and decimation using multiple constant multiplication techniques
- 2006
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Ingår i: IEEE Asia Pacific Conference on Circuits and Systems,2006. - Piscataway : IEEE. ; , s. 924-927
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Konferensbidrag (refereegranskat)abstract
- Multiple constant multiplication (MCM), i.e., realizing a number of constant multiplications using a minimum number of adders and subtracters, has been an active research area for the last decade. Almost all work has been focused on single rate FIR filters. However, for polyphase interpolation and decimation FIR filters there are two different implementation alternatives. For interpolation, direct form subfilters lead to fewer registers as they can be shared among the subfilters. The arithmetic part corresponds to a matrix vector multiplication. Using transposed direct form subfilters, the registers can not be shared, while the arithmetic part has the same input to all coefficients, and, hence, the redundancy between the coefficients is expected to be higher. For decimation filters the opposite holds for direct form and transposed direct form subfilters. In this work we discuss the trade-off between adders/subtracters and registers, and present implementation results for area, speed, and power for different realizations
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| 2. |
- Johansson, Håkan, 1969-, et al.
(författare)
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Adjustable fractional-delay FIR filters using the Farrow structure and multirate techniques
- 2006
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Ingår i: Asia Pacific Conference on Circuits and Systems,2006. ; , s. 1055-1058
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Konferensbidrag (refereegranskat)abstract
- The Farrow structure can be used for efficient realization of adjustable fractional-delay finite-length impulse response (FIR) filters, but, nevertheless, its implementation complexity grows rapidly as the bandwidth approaches the full bandwidth. To reduce the complexity, a multirate approach can be used. In this approach, the input signal is first interpolated by a factor of two via the use of a fixed half-band linearphase FIR filter. Then, the actual fractional-delay filtering takes place. Finally, the so generated signal is downsampled to retain the original input/output sampling rate. In this way, the bandwidth of the fractional-delay filter used is halved compared to the overall bandwidth. Because the complexity of halfband linear-phase FIR filter interpolators is low, the overall complexity can be reduced. In this paper, we present more implementation details, design trade-offs, and comparisons when the filters are implemented using multiple constant multiplication techniques, which realize a number of constant multiplications with a minimum number of adders and subtracters.
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| 3. |
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| 4. |
- Aksyutina, Yu, et al.
(författare)
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Lithium isotopes beyond the drip line
- 2008
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 666:5, s. 430-434
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Tidskriftsartikel (refereegranskat)abstract
- The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.
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| 5. |
- Aksyutina, Yuliya, 1983, et al.
(författare)
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Properties of the 7He ground state from 8He neutron knockout
- 2009
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 679:3, s. 191-196
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Tidskriftsartikel (refereegranskat)abstract
- The unbound nucleus 7He, produced in neutron-knockout reactions with a 240 MeV/u 8He beam in a liquid-hydrogen target, has been studied in an experiment at the ALADIN-LAND setup at GSI. From an R-matrix analysis the resonance parameters for 7He as well as the spectroscopic factor for the 6He(0+) + n configuration in its ground-state have been obtained. The spectroscopic factor is 0.61 confirming that 7He is not a pure single-particle state. An analysis of 5He data from neutron-knockout reactions of 6He in a carbon target reveals the presence of an s-wave component at low energies in the α+n relative energy spectrum. A possible low-lying exited state in 7He observed in neutron knockout data from 8He in a carbon target and tentatively interpreted as a Iπ=1/2− state, could not be observed in the present experiment. Possible explanations of the shape difference between the 7He resonance obtained in the two knockout reactions are discussed in terms of target-dependence or different reaction mechanisms at relativistic energies.
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| 6. |
- Blad, Anton, 1981-, et al.
(författare)
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A General Formulation of Analog-to-Digital Converters Using Parallel Sigma-Delta Modulators and Modulation Sequences
- 2006
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Ingår i: Asia Pacific Conference on Circuits and Systems,2006. - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- A formulation based on multirate theory is introduced for analog-to-digital converters using parallel sigma-delta modulators in conjunction with modulation sequences. It is shown how the formulation can be used to analyze a system's sensitivity to channel mismatch errors by means of circulant and pseudo-circulant matrices. It is demonstrated how the time-interleaved-modulated (TIM), Hadamard-modulated (HM) and frequency-band decomposition (FBD) converters can be viewed as special cases of this more general description, and it is shown why the TIM and HM ADCs are sensitive to channel mismatch errors, whereas the FBD ADCs are not.
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| 7. |
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| 8. |
- Blad, Anton, 1981-, et al.
(författare)
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Design Trade-Offs for Linear-Phase FIR Decimation Filters and SD-Modulat ors
- 2006
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Ingår i: 14th European Signal Processing Conference,2006. - Wien, Austria : EURASIP.
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Konferensbidrag (refereegranskat)abstract
- In this paper we examine the relation between signal-to-noise-ratio, oversampling ratio, transition bandwidth, and filter order for some commonly used sigma-delta-modulators and corresponding decimation filters. The decimation filters are equi-ripple finite impulse response filters and it is demonstrated that, for any given filter order, there exists an optimum choice of the stopband ripple and stopband edge which minimizes the signal-to-noise-ratio degradation.
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