In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrab...In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrable or Lebegue integrable on the real number line. They are in fact the generalization of the classic sinc function. Two approaches of constructing the generalized sampling functions are reviewed. Their properties such as cardinality, orthogonality, and decaying properties are discussed. The interactions of those functions and Hilbert transformer are also discussed.展开更多
The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation a...The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. We perform multiparticle simulation to control the halo by using the sample function controller. The numerical results show that our control method is effective. We also find that the radial ion density changes when the ion beam is in the channel： not only can the halo-chaos and its regeneration be eliminated by using the sample function control method, but also the density uniformity can be found at the beam＇s centre as long as an appropriate control method is chosen.展开更多
Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant...Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant-squared space segment pattern on radar phased array antenna is synthesized using it. Through simulation and analysis,it can be used fewer elements to make the same synthesis effect on the pattern with the traditional Woodward method. And if the same number of elements is used,the synthesized pattern using the improved method will have better approach to the sample function,narrower beam width,and higher gain.展开更多
文摘In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrable or Lebegue integrable on the real number line. They are in fact the generalization of the classic sinc function. Two approaches of constructing the generalized sampling functions are reviewed. Their properties such as cardinality, orthogonality, and decaying properties are discussed. The interactions of those functions and Hilbert transformer are also discussed.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10247005 and 70071047） and the Scientific Research Foundation of China University of Mining and Technology for the Young （Grant No 2005A037）.
文摘The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. We perform multiparticle simulation to control the halo by using the sample function controller. The numerical results show that our control method is effective. We also find that the radial ion density changes when the ion beam is in the channel： not only can the halo-chaos and its regeneration be eliminated by using the sample function control method, but also the density uniformity can be found at the beam＇s centre as long as an appropriate control method is chosen.
文摘Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant-squared space segment pattern on radar phased array antenna is synthesized using it. Through simulation and analysis,it can be used fewer elements to make the same synthesis effect on the pattern with the traditional Woodward method. And if the same number of elements is used,the synthesized pattern using the improved method will have better approach to the sample function,narrower beam width,and higher gain.
