the discrete fourier transform its properties and applications

... Trang 17The models are the problem!● The compression improves because we better predict the next symbol. ● Problem: ● Larger is k, smaller is the compress Trang 18The models are the problem!● The ... predict the next symbol. ● Problem: ● Larger is k, smaller is the compress ● but we have to store more tables: ● O( σk+1 log σ ) bits in the worst case Trang 19The models are the problem!● The compression ... way: sort the symbol lexicographically Which is the problem? The transformation is not reversible! There are 997.920 distinct strings with Trang 27Rearranging the input● Idea! – Permute the input

Ngày tải lên: 30/10/2015, 18:04

... Now we focus on DT signals for a while The discrete Fourier transform or DFT is the transform that deals with a finite discrete-time signal and a finite or discrete number of frequencies Which frequencies? ... −1 and then take the N -point inverse DFT of {S[k]}k=0 to get {s[n]}k=0 How does s[n] relate to h[n] and x[n]? The resulting s[n] is not the ordinary convolution of h[n] and x[n], but rather the ... can simply multiply the two transforms and then “look up” the inverse transform to get the convolution What if we want to automate this procedure using a computer? Right away there is a problem

Ngày tải lên: 08/06/2014, 20:19

... have been introduced, such as the wavelet transform, the Wigner-Ville distribution, the Radon-Wigner transform, and the Fractional Fourier transform Fractional Fourier transform, as a new time-frequency ... Since the chirp rates for different harmonics are different, the FrFT is emphasizing the Nth harmonic when setting the transform order according to N times the pitch rate k The transform angle is then ... basis functions and of the signal match The step search method [16] is simple, but a compromise has to be made between the computational complexity and the accuracy The method based on the location

Ngày tải lên: 21/06/2014, 20:20

... Approach to Linear Transform Approximations with Applications to the Discrete Cosine Transform Yinpeng Chen and Hari Sundaram The Katherine K Herberger College of the Arts and the Ira A Fulton ... is the distortion due to the approximation Ti for the ith element of the input set (i.e., xi ), and d(·) is the distortion measure In this paper, d(·) is the standard Euclidean norm Definition The ... problem Let Q denote the cardinality of the given approximation candidate set Φ and let N the cardinality of the input set X Then the number of possible achievable C-D pairs is N Q Therefore, computational

Ngày tải lên: 21/06/2014, 22:20

... projection The accuracy of the DRT is determined byΘ (the number of angles),β (the number of beams per angle), and the accuracy of the interpolation method Note that the continuous form of the Radon transform ... implemented In the first stage, the classifier combines the decision results of the neural networks and the Euclidean dis-tance obtained using the three feature sets The results of the first stage ... to the other non-zero components before the decimated vector is shrunk or expanded Since the dimension of the feature vectors are high compared to the number of these additional components, the

Ngày tải lên: 23/06/2014, 01:20

... convolutions of the Fourier-cosine and Fourier-sine transforms As usual, there exist different convolutions for the same transform, and a transform may be a convolution for different transforms Section ... convolutions for the Fourier transforms with geometric variables and four generalized convolutions for the Fourier-cosine, Fourier-sine transforms With respect to applications, by using the constructed ... call Fh the Fourier transform with shift, and Fh−1 its inverse transform The inversion formula of Fh is proved by Lemma 3.7 Put γ1 (x) = e− |x| Theorem 2.2 If f, g ∈ L1 (Rn ), then each of the integral

Ngày tải lên: 18/12/2017, 05:17

... focused on the identification of the intrinsic defects responsible for the SI properties of SiC At the same time, investigation of the role, which they play in the trapping, recombination, and ionization ... 2 Samples and experimental technique The nature of the intrinsic defects in HPSI 4H and 6H-SiC was studied on the samples grown up by the PVT method at the Cree Research Inc and Bandgap Technologies ... focused on the identification of the intrinsic defects responsible for the SI properties of SiC At the same time, investigation of the role, which they play in the trapping, recombination, and ionization

Ngày tải lên: 20/06/2014, 04:20

... nitrogen and boron impurities, and the other two are thermally stable intrinsic defects with S = 1/2, labeled X and P 1 , P 2 in 4H SiC and XX and PP in 6H SiC. The X and XX, P 1 and PP defects ... calculated as the right-hand side of rate equations (3), and that of the second derivative, as the derivative of the right- hand side of Eqs. (3). The solutions for the variables at the time t ... calculated as the right-hand side of rate equations (3), and that of the second derivative, as the derivative of the right- hand side of Eqs. (3). The solutions for the variables at the time t

Ngày tải lên: 20/06/2014, 04:20

... hydrogen at the total flow rate of 2 slm. After the deposition, the chemical bond and the composition of the obtained film are evaluated using the XPS. Figure 6 (a) and (b) show the XPS spectra ... hydrogen at the total flow rate of 2 slm. After the deposition, the chemical bond and the composition of the obtained film are evaluated using the XPS. Figure 6 (a) and (b) show the XPS spectra ... used for adjusting the ratio of silicon and carbon in the silicon carbide film. Throughout the deposition process, the hydrogen gas flow rate is 2 slm. Figures 2, 3 and 4 show the film deposition

Ngày tải lên: 20/06/2014, 04:20

... oxidants, and the superscript ‘I’ means the position at the SiC–SiO2interface According to the Henry’s law, the value of CI O2 is proportional to the oxygen partial pres-sure Therefore, the initial ... oxidants, and the superscript ‘I’ means the position at the SiC–SiO2interface According to the Henry’s law, the value of CI O2 is proportional to the oxygen partial pres-sure Therefore, the initial ... shown in the figure are the growth rates given by the Si and C emission model (solid lines), the Si emission model, and the model that does not take account of both Si and C emission, i.e., the Deal-Grove

Ngày tải lên: 20/06/2014, 04:20

... including the edge condition at the angular points of the waveguide cross-section counter and the condition at infinity. The longitudinal components of the electric field and the magnetic field at the ... including the edge condition at the angular points of the waveguide cross-section counter and the condition at infinity. The longitudinal components of the electric field and the magnetic field at the ... vector. Also ε r is the relative permittivity and μ r is the relative permeability of the medium. The electric and magnetic constants ε 0 , μ 0 are called the permittivity and the permeability

Ngày tải lên: 20/06/2014, 04:20

... evaluated and fed as input data for the small-signal analysis The edges of the depletion layer of the diode, which are fixed by the DC analysis, are taken as the starting and end points for the small-signal ... the big difference is the energy bandgap Standard semiconductors have almost three times smaller bandgaps than the wide bandgap materials SiC and GaN However, it is probably the ten times larger ... the big difference is the energy bandgap Standard semiconductors have almost three times smaller bandgaps than the wide bandgap materials SiC and GaN However, it is probably the ten times larger

Ngày tải lên: 20/06/2014, 04:20

... namely Ni31Si12, Ni2Si and NiSi The others form via the peritectic reaction The synthesis method of the nickel silicides in Ni-Si system includes conventional melting and casting and solid state reaction ... the formation of the compounds depends on the relative amounts of the Ni and Si available for the reactions, the annealing temperature, the atmosphere, and impurities contained in the layers Important ... compounds and ternary phase Furthermore, only Ni2Si can be in equilibrium with both C and SiC The elements Si and Ni have a strong affinity to one another The thermodynamic driving force for the Ni/SiC

Ngày tải lên: 20/06/2014, 04:20

... current than the matrix and the majority of the current through the sample Therefore, the percolation of the SiCw is of principal importance in the determination of the composite electrical properties ... current than the matrix and the majority of the current through the sample Therefore, the percolation of the SiCw is of principal importance in the determination of the composite electrical properties ... dielectric loss in the food itself (2) air convection from the ceramic and (3) thermal conduction across the thermal gradient at the ceramic-food interface Due to (3) and the fact that food moisture

Ngày tải lên: 20/06/2014, 04:20

... as the temperatures, pressures and thermal fluxes reached at the stagnation point, but also surface properties In particular, if the stagnation pressure depends on the re-entry trajectory, the ... and the heat flux are also greatly influenced by the emissivity and recombination efficiency (catalycity) values of the employed material Consequently the choice of the material is not only the ... shape and dimension of the structural part The design of shape and dimensions of that element must consider a lot of parameters such as the temperatures, pressures and thermal fluxes reached at the

Ngày tải lên: 20/06/2014, 04:20

... in the 88 kV, circuits TAU-01, JAG-01 and JAG-02 The three phases of each circuit were named as a, b and c Table 5 shows the results The comparison between the results from the field and from the ... to the radio influence voltage (RIV) and thermovision tests In the three tests, leakage current, RIV and thermovision, the phase-to-ground voltages 51 kV and 80 kV were applied to the 88 kV and ... to the thermal imaging obtained along the sample, from top to bottom Each of the four sides of the sample had its maximum and minimum temperatures determined, and the difference (t) between these

Ngày tải lên: 20/06/2014, 04:20

... on the shape of the waveform being decomposed. Chapter 8- The Discrete Fourier Transform 145 Type of Transform Example Signal Fourier Transform Fourier Series Discrete Time Fourier Transform Discrete ... another chunk of data. Let's see how this applies to the topic at hand: the Discrete Fourier transform. Notation and Format of the Real DFT As shown in Fig. 8-3, the discrete Fourier transform ... we look at the mathematics and algorithms of the Fourier decomposition, the heart of the DFT. The Family of Fourier Transform Fourier analysis is named after Jean Baptiste Joseph Fourier (1768-1830), a...

Ngày tải lên: 13/09/2012, 09:49

... TO THE DFT Page 5 Having completely understood the DFT and its inverse mathemati- cally, we go on to proving various Fourier Theorems, such as the “shift theorem,” the “convolution theorem,” and ... travel the farthest and resonate near the helicotrema. The membrane resonance effectively “shorts out” the signal energy at that frequency, and it travels no further. Along the basilar membrane there are ... of the mathematical group consisting of the Mth roots of unity and their products. We will learn later that the Nth roots of unity are used to generate all the sinusoids used by the DFT and its...

Ngày tải lên: 31/03/2014, 15:21

... binary with the bits flipped left-for-right (such as in the far right column in Fig. 12-3). 225 CHAPTER 12 The Fast Fourier Transform There are several ways to calculate the Discrete Fourier Transform ... is placed in the real part of the time domain, and the other signal is placed in the imaginary part. After calculating the complex DFT (via the FFT, of course), the spectra are separated using the even/odd ... of the frequency spectrum. Therefore, the frequency spectra are combined in the FFT by duplicating them, and then adding the duplicated spectra together. In order to match up when added, the...

Ngày tải lên: 13/09/2012, 09:50

... Laplace and z-transforms. These complex transforms are the foundation of theoretical DSP. The Real DFT All four members of the Fourier transform family (DFT, DTFT, Fourier Transform & Fourier ... Fourier Transforms A time domain signal can be either continuous or discrete, and it can be either periodic or aperiodic. This defines four types of Fourier transforms: the Discrete Fourier Transform ... the Discrete Fourier Transform (discrete, periodic), the Discrete Time Fourier Transform (discrete, aperiodic), the Fourier Series (continuous, periodic), and the Fourier Transform (continuous, aperiodic)....

Ngày tải lên: 13/09/2012, 10:20