| 1. |
- Tran, To, et al.
(författare)
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A Semi-Infinite Quadratic Programming Algorithm with Applications to Channel Equalization
- 2003
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Konferensbidrag (refereegranskat)abstract
- This paper is based on DNCA (Dual Nested Complex Approximation) for optimizing communication channel equalizers using semi--infinite quadratic programming. The optimality criterion for the equalizer is either to minimize the complex deviation in the passband or to minimize its stopband energy when subjected to a specified peak side lobe level in the stopband. Additional linear constraints can be used to form the response by means of group delay, nulls etc. The design approach is applied to a numerical example which deals with the design of a complex communication channel equalizer.
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| 2. |
- Tran, To, et al.
(författare)
-
Design and Improvement of Flattop Windows with Semi-Infinite Optimization
- 2004
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Konferensbidrag (refereegranskat)abstract
- Digital and analog window optimization problems are often characterized by a few number of variables with many constraints. In some cases the optimization problem becomes semi-infinite, i.e. a finite number of variables with an infinite set of constraints. This paper presents a method for flattop window design and enhancement using the Dual Nested Complex Approximation (DNCA) algorithm. Flattop windows can be used for accurate amplitude measurements in spectral analysis and can also be used to design FIR filters with very high stopband attenuation. This paper proposes using the DNCA scheme to solve the optimization problem, due to its low computational complexity and memory consumption. It can be run on any desktop computer. The framework of the DNCA scheme is presented together with two examples; one concerning the design of an enhanced version of the ISO 18431-2 flattop window and the other concerns the design of a flattop window which is comparable with the commercial P-401.
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| 3. |
- Tran, To, et al.
(författare)
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High accuracy windows for today's 24bit ADC's
- 2004
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Konferensbidrag (refereegranskat)abstract
- This paper presents a new high accuracy window design method based on semi-infinite linear programming by using the Dual Nestled Complex Approximation (DNCA) algorithm. The paper presents a general window design specification, the formulation of the corresponding semi-infinite linear programming solution and several highly optimized window design examples. The paper illustrates the capability to enhance the sidelobe attenuation of the new upcoming ISO 18431-2 flattop window standard from the international organization for standardization. The procedure of enhancing the ISO flattop window can be directly applicable to any other existing windows. Flattop windows are commonly available in frequency analyzers for accurate amplitude measurements of harmonic tones in presence of noise. Moreover, it is possible to design high accuracy windows with more than 150dB sidelobe attenuation with the proposed method as well. Such high sidelobe attenuation is for example needed in today's 24bit equivalent 1bit-Sigma-Delta ADC:s, where high frequency noise is generated.
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| 4. |
- Tran, To, et al.
(författare)
-
Window Design and Enhancement using Chebyshev
- 2004
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Konferensbidrag (refereegranskat)abstract
- This paper presents a new and versatile framework to window design based on a semi-infinite linear programming approach by using the Dual Nestled Complex Approximation (DNCA) algorithm. The paper considers a practical problem formulation, the general window design specification and the corresponding optimum solution. The DNCA linear programming algorithm is presented and several highly optimized window design examples included. Furthermore, the capability of the design method by enhancing the sidelobe attenuation of existing windows such as Flattop windows is illustrated as well. Flattop windows are commonly available in frequency analyzers for accurate amplitude measurements of harmonic tones in presence of noise. However, the design method can be directly applied to any other existing window, in purpose to enhance its performance. With the proposed method it is possible to design windows with more than 150dB sidelobe attenuation. A relevant application where such high precision windows is needed are in today's 24bit equivalent 1bit-Sigma-Delta ADC:s, where high frequency noise is generated.
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