properties of discrete time fourier transform ppt

Ngày tải lên: 21/06/2014, 20:20

... Trong miền tần số: phương pháp Fourier Transform. - Trong miền thời gian và tần số: STFT( Short Time Fourier Transform) . 2.4.1. Phương pháp Fourier: 2.4.1.1. Biến đổi Fourier: Cho một hàm f(t) ... kết thúc của sự kiện thì Fourier không phát hiện được. 2.4.2. Phương pháp STFT: Để đạt được một biến đổi Fourier cục bộ, chúng ta có thể định nghĩa một biến đổi Fourier cửa sổ. Tín hiệu đầu ... đổi Fourier của nó được định nghĩa: () () () tfedtetfF titj , ωω ω == ∫ ∞ ∞− − (2.14) Biến đổi Fourier ngược là: () () ∫ ∞ ∞− = ωω π ω deFtf tj 2 1 (2.15) Giả sử rằng biến đổi Fourier...

Ngày tải lên: 01/04/2013, 16:14

... infinite set of possible signals is converted into a finite set. The next step of encoding maps the finite set of discrete time, continuous amplitude signals into a finite set of discrete time, discrete amplitude ... as its domain. A discrete time, continuous amplitude signal has R as its range. A discrete time, discrete amplitude signal has Z as its range. Here, the focus is on discrete time signals. Quantization ... discrete time signals. Quantization is the process of approximating any discrete time, continuous amplitude signal into one of a finite set of discrete time, continuous amplitude signals based on a particular...

Ngày tải lên: 18/10/2013, 04:15

... in favour of a specific binding of phosphate to cyto- chrome c 3 [23] instead of a simple electrostatic effect of increased ionic strength at least up to 0.2 m concen- tration. The region of positively ... approximation of the redox centres of the donor and acceptor, and that the reduction potentials ensure a favourable driving force, which is one of the main determinants of the rate of electron ... Experimental measure- ments of the reduction potentials of proteins involved in complexes have been reported [5–7], but the effect of partner binding on the microscopic properties of the redox centres...

Ngày tải lên: 19/02/2014, 17:20

... equation of motion approach, we have investigated the electronic transport properties of an Aharonov-Bohm (AB) ring in the presence of a magnetic field with a quantum dot inserted in one arm of the ... for the ring-dot using the equations of motion method [17]. The equations of motion method of the dot Green function gives rise to an infinite order system of higher-order Green functions. An approximation ... system of equations, thus producing the closed set of equations. To do the truncation, we approximate the Green functions up to the second order of U. This truncation ensures that most of the...

Ngày tải lên: 05/03/2014, 14:20

Ngày tải lên: 06/03/2014, 17:20

... Hi-Stat Discussion Paper Series No.45 Risk Properties of AMU denominated Asian Bonds Junko Shimizu and Eiji Ogawa November 2004 ... Research Unit for Statistical Analysis in Social Sciences A 21st-Century COE Program Institute of Economic Research Hitotsubashi University Kunitachi, Tokyo, 186-8603 Japan http://hi-stat.ier.hit-u.ac.jp/...

Ngày tải lên: 15/03/2014, 07:20

... polynomiaUy bigger than the size of a grammar for the language itself. The proof of this claim rests on inspection of one of the standard proofs, say Hopcroft and Ullman [5]. The result is ... The number of strings in A is less than or equal to the number of ways of selecting one of the u strings. Consider the u string to the left of the boundary which z overlaps. Because of wraparound, ... f~(cn). Proof. This proof is really just a generalization of the proof of Theorem 1. It uses, however, the Q subsets in a way that the proof of Theorem 1 does not. First, we drop the n subscript...

Ngày tải lên: 17/03/2014, 20:20

... and cost-in short, the engineering properties of a material. Other properties may be of importance, but, if a polymer does not have a balance of these properties, its chances for commercial ... Krevelen, Properties of Polymers, Their Estimation and Correlation with Chemical Structure, Elseview, New York, 1976, p. 303. 25. D. W. Van Krevelen and P. J. Hoftyzer, Properties of ... ASTM D638. ESTIMATION OF MECHANICAL PROPERTIES OF POLYMERS 1343 Data calculated Temperature, K Figure 9 Tensile modulus of polystyrene as a function of temperature. 1. Shear...

Ngày tải lên: 01/04/2014, 00:20

... degrees of freedom k and n, we generalize it from discrete to continual [1,2]. In addition, we can advance from the field of the natura l integers o f the dimensions–degrees of freedom of cube ... 2011:60 http://www.advancesindifferenceequations.com/content/2011/1/60 Page 8 of 14 comes down to zero. The greatest values of the considered functions are infinite, when k 0 = ∞. 2.7. The first derivatives of the ch1 function of HC in relation to the degree of freedom ... 2)ψ 2 (υ +1)+ψ 4 (k + n − 2)  . In general, the HC of the mth derivative of n can be defined on the basis of the pro- duct of polygamma (psi) polynomial of the mth degree and HC. Its general form is...

Ngày tải lên: 20/06/2014, 21:20

... conductivities of nanofluids The effects of both temperature and mass fraction of the nanoparticles on the viscosities of the nanofluids were investigated. Figure 5 shows the results of viscosity ... qC b Figure 6 Thermal conductivity of nanofluids: (a) Variation of thermal conductivity of nanofluids at 25°C with mass fraction of nanoparticles; (b) variation of thermal conductivity with temperature ... Netherlands). A Nexus 470 Fourier transform infrared spectrometer (NICOLET, USA) was employed to observe the changes of organic functional groups. Preparation of nanofluids Three types of nanofluids were...

Ngày tải lên: 21/06/2014, 03:20

... concentrations of ferro-nanofluids were applied to the magnetic cores of transformers. The performance of transformers with magnetic cores of air Figure 6 The coupling coefficients of transformers ... factor of coils of transformers with different magnetic cores. Owing to the fact that the increase of resistance is larger and faster than that of inductance with the presence of Fe 3 O 4 nanofluids, ... ferro-nanofluid was applied as a liquid magnetic core in a transformer. The performance of the transformer with t he ferro- nanofluids was measured, simulated, and compared with that of a transformer...

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Ngày tải lên: 11/08/2014, 15:20