A Koch multiband fractal array using Kaiser Window technique

Fractional Fourier transform (FRFT) is generalization of Fourier transform. It has an adjustable parameter in the form of $$\alpha$$ rotational angle that makes it more useful in the various fields of science and engineering. In this paper, an analysis of Kaiser and Gaussian window functions is obtained in the FRFT domain. The behavior of these window functions is observed in terms of spectral parameters along with their special cases. The effect of their behavior is applied in FIR filter implementation and tunes its transition band. By changing the order of the FRFT, the variation in the transition width of windowed FIR filter is obtained which makes it possible to vary the stop-band attenuation. While designing a new filter, this tuning method saves significant time to compute filter coefficients. To validate the results, tuning of the FIR filter with Gaussian and Kaiser window functions is achieved in FRFT domain and the performance of the filter is measured in terms of stop-band attenuation.

In processing long sequences of data either for the purpose of filtering or spectal analysis, one generally divides the data into segments. The elements of each segment are usually multiplied by a set of weights, referred to as a to reduce certain undesired effects of the division into short sequences (see Ref. 1). A simple effective way to design a window is to use one of the many window functions such as the Hanning, Hamming (1) or Kaiser (2) windows. These are defined by simple formulas in which parameters can be selected so that the frequency response of the window will have the desired center-lobe width and side-lobe attenuation. These procedures have the advantage that they require no more than a pocket calculator. On the other hand, if one is equipped with a large computer with filter design programs such as those in the IEEE Program Book (3), one may find it easier, in some cases, to design better windows by the direct calculation of an optimized filter. The present work shows the results of computations of FIR filters and how they compare with Hanning, Hamming and Kaiser windows. We get, for typical filter parameters, a side-lobe attenuation of 31.5 dB for the Hanning window, 42.0 dB for the Hamming window, 41.0 dB for the Kaiser window and 47.2 dB for the FIR window.

Filtering is a necessary part from the digital signal processing in radar. This research is focused on comparing the performance of 4 windowing methods for designing a digital filter with finite impulse response (FIR) type or a 9,3 GHz surveillance radar system. In this study, Blackman, Bartlett, Hanning, and Kaiser windows are modelled in QT software. The experiment is performed by picking 512 and 1024 frame length in all frequency bands. Parameters examined are the amplitude and the frequency. Result showed that Kaiser has the best performance for this radar application.

One of the most major trends in modern microwave signals is the shift toward wider bandwidths. Analog wideband receiver designs can provide accommodation of the technology-stressing bandwidths, but come up to a cost of reduced flexibility. Digital approaches, alternatively, provide flexibility in receiver signal processing, but they are limited by analog-to-digital converter resolution and power consumption. In this paper, design and implementation of a 1-GHz signal bandwidth digital receiver, which uses the Kaiser window function and compensation technique, is presented. The Kaiser window reduces the spectral leakage by eliminating the discontinuities at the time window edges and the compensation uncovers the weak signal for extension of the two-signal spurious-free dynamic range (SFDR) of the receiver. The combination of both techniques extends the two-signal SFDR of the receiver to 24 dB. A novel hardware implementation of the Kaiser window and the compensation method is presented

Separation of coincident speech sources using microphone arrays is a challenging problem. Radial filters can be designed in the spherical harmonic domain to separate coincident speech sources effectively. Limited studies have been conducted on polynomial based near-field radial filter design in the spherical harmonic domain earlier. In this paper, a radial filter design method using a frequency domain Kaiser window function is proposed. The magnitude response of the Kaiser window function exhibits sharp notches, making it a good candidate for the design of radial notch filters. The polynomial expansion of the Kaiser window can be utilized for modeling the spherical array beamformer output. Improved white noise gain and directivity index are noted in the radial filters designed using the Kaiser window function. The radial filter is also used to separate co-incident speech sources. Experimental results on coincident speech source separation indicate better LSD, PESQ, and SDR scores than existing approaches.

In large amount applications appreciate Finite Impulse Response filters, Fast Fourier Transform, Signal Processing Technique and measurements, forced upon ∼45dB or ultimately less side lobe magnitudes. However, the setback is prompt in window based FIR filter design lies in its side lobe magnitude that are higher than the specification of application. The expected hybrid window Technique has transcend attitude like minimum side lobe peak and higher side lobe peak attenuation compared to the several generally used windows with main lobe width(−3dB) of 0.11328. The proposed window has reliant side lobe attenuation of −72.7 dB and peak side lobe amplitude of −98 dB for the filter term of N=35. The studied results also unmask significant performance upgrading of the coming window compared to Rectangular, Hanning, Hamming, Blackman and Kaiser Windows. Finally, the approaching window is applied to design Low pass FIR filter prove the simplicity of the window

Digital filter plays an important role in the advanced era of communication system. Digital filters basically provide high attenuation to the unwanted ones and offer very low or ideally zero attenuation to desired signal components when its impulse response is adjusted as per requirement. But the design of a digital filter satisfying all the required conditions is a challenging task. In this paper, design techniques of low pass FIR filters using Tukey window, Kaiser Window, and Gaussian window methods are presented. The magnitude and phase responses are demonstrated in the simulation section for the different design techniques of digital low pass FIR filters. From the simulation results, it is observed that for a longer length the FIR filter has a sharper cut-off FIR filter and a narrow transition band.

SummaryThe optimization of the non‐uniform planar array antenna parameter in order to minimize the signal interference in the electromagnetic environment through null placement is one of the most important areas of investigation in the field of wireless communication. This study deals with an effective method of synthesis of a quadrant symmetric sparse planar array antenna using the novel implementation of the well‐known meta‐heuristic optimization algorithms, namely, symbiotic organism search (SOS) and moth flame optimization (MFO) algorithms. The objective of this work is to place multiple small and wide nulls at the desired angles and simultaneously minimize the side lobe levels using a nonlinear mathematical approach. Three examples are presented with constraints that include the inter‐elemental distance, fixed number of array elements in the aperture, and the aperture size. The radiating antenna array elements are considered to have fixed uniform current distribution. The meta‐heuristic optimization approach offers the advantages of avoiding the infeasible solution while finding the best optimal set of element positions to reduce side lobe level in the desired radiation pattern. The radiation pattern characteristics and the computation time associated with each example and each algorithm are recorded and compared for arriving at the conclusion. The superiority of SOS is found in terms of the optimized side lobe levels. At the same time, both algorithms are found to be efficient in positioning the symmetric nulls in desired locations in the radiation pattern successfully. When compared with the published papers, proposed approach yields better results confirming the effectiveness of the performance of these algorithms.

A new function is found and is defined as sinc sum function by the author. It has outstanding properties of stairs shape, global symmetry, local symmetry, derivative formula simplicity, local extreme certainty, oscillation regularity, extreme value stability, etc. These properties are proved. Geometry meaning is explained. As an application of the function, the author has developed a new method to design FIR digital filters with adjustable weights. Filter formula in time domain is the weighted sum of sub-filters. A novel form of frequency response expression is deduced which is the sum of sinc sum functions. One of the remarkable characteristics of the form is that weights of sub-filters can be directly calculated according to the expression. Completing the calculation of the weights means finishing the design of a filter. The weights can be either adjustable or fixed. A method to determine the weights are given. Three examples using the method are selected for the consideration that the new method can be easily compared with some famous window methods. Three new filter formulas are produced. Much better performances can be obtained using these formulas compared with using Hanning window and Blackman window respectively. And the performance designing with the new method is slightly better than that with Hamming window. For fixed weights it is almost as easy as using fixed window to calculate filter coefficients.

Comparative exploration on EEG signal filtering using window control methods

The design of a millimeter wave (mmW) antenna for the 5G mobile applications is presented in this paper. The designed antenna has dimensions of 10×10×0.245 mm<sup>3</sup>. This includes the copper ground plane. The resonance of the proposed mmW antenna lies within the range of 33 GHz and 43 GHz. These frequency bands are covering the 5G proposed band in terms of the signal speed, data transmission, and high spectral efficiencies. Computer simulation technology (CST) software is used to simulate the proposed 5G antenna including the characteristics of S-parameters, gain, and radiation pattern. Simulation results show that the return loss at resonant frequencies goes -22 dB, which satisfies the requirements of 5G mobile technology.

In this paper is simulated the time- domain unit sample response of sine function and frequency- domain response of sine function. Digital filter plays an important role in today’s world of communication and computation. Without digital filter we cannot think about proper communication because noise occurs in channel. For removing noise or cancellation of noise we use various type of digital filter. In signal processing, there are mainly two types of filters exist .they are the Finite Impulse Response (FIR) filter and Infinite Impulse Response (IIR) filter. Finite Impulse Response (FIR) filter can be designed form Infinite Impulse Response (IIR) filter by various techniques. The widely used technique is the window technique. This paper low-pass FIR filter is implemented using an efficient adjustable window function based on Hamming window and Blackman window function. The output of the FIR design by Blackman window and the Blackman window are shown in this paper by simulating the code in Matlab. The Matlab program returns with a satisfactory result with proper magnitude plotting.

It is possible to thin an array as well as to improve radiation pattern characteristics with an appropriate spacing function. Array thinning plays a very important role in array synthesis. To analyze the effect of thinning by considering a modulated spacing function. Using a specified spacing function, radiation patterns are evaluated for different array lengths. It is found that the near-in-side lobe level is reduced for a modulated spacing function and that the main beam width is found to remain constant. These advantages are not found in the case of uniform spacing. Even after thinning the array, the modulated spacing function is found to improve the overall radiation pattern characteristics. Although some studies are made by the researchers on thinning, the effect of thickening is not reported in the literature. In view of the above facts, intensive studies are carried out to investigate linear arrays with thickening as well as thinning. The patterns are numerically evaluated for different arrays and the radiation patterns are presented for different arrays. The investigations reveal that thickening has caused the reduction of null to null beam width without deteriorating the side lobe levels. On the other hand thinning has resulted in raising the side lobe levels as well as the beam width. If thinning is not carried out properly the resultant radiation patterns contain even grating lobes.

In array antennas, sometimes the desired radiation pattern cannot be obtained due to coupling between element antennas, reflections from the surroundings, or amplitude and phase error of the power supply circuits or failures. In these cases, it is necessary to regenerate the desired radiation pattern by estimating the excitation amplitude and phase of the array antennas. Among methods of estimation of the excitation amplitude and phase, the rotation element field vector method of element antennas is used for the phased array antenna with variable phase shifters, and the planar near-field measurement method is used for the array antennas with no variable phase shifters. The former is limited to phased array antennas, and the latter requires a large-scale scanner for the measurement and results in increased measurement time with larger-scale array antennas. In this paper, we propose a method of estimation of excitation amplitude and phase using the radiation pattern of array element antennas and the measured radiation pattern of the array antennas. Two methods are proposed here; the first method of estimation is the least-squares method using the electrical field as the measured radiation pattern, and the second is the repeating calculation method using the electrical power as the measured radiation pattern. We describe here the principle and experimental results when the first method is used, and the principle and the effectiveness of selection of the initial value for the second method is confirmed by numerical results. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(9): 102–110, 2000

An iterative method for the design of two-band quadrature mirror filter (QMF) banks proposed by Cruesere and Mitra is examined and improved by designing the prototype filters using window method instead of equiripple method. The Kaiser window and Chebyshev window functions are used in the design of prototype filters. The cut-off frequency has been adjusted in this improved method instead of passband frequency which is the case in Cruesere and Mitra algorithm. The paper concludes with design results and comparisons that show that our new improved method takes less computational effort when compared with Cruesere and Mitra method.