The Experts below are selected from a list of 1938 Experts worldwide ranked by ideXlab platform
Kavita Khare - One of the best experts on this subject based on the ideXlab platform.
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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1 Scale-Free Hyperbolic CORDIC Processor and its Application to Waveform Generation
2016Co-Authors: Supriya Aggarwal, Pramod Meher Senior K. Member, Kavita KhareAbstract:Abstract—This paper presents a novel completely scaling-free CORDIC algorithm in rotation mode for Hyperbolic Trajectory. We use most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iterations. By storing the sinh/cosh Hyperbolic values at octant boundaries in a ROM, we can extend the range of convergence to the entire coordinate space. Based on this, we propose a pipeline Hyperbolic CORDIC processor to implement a direct digital synthesizer (DDS). The DDS is further used to derive an efficient arbitrary waveform generator (AWG), where a pseudo-random number generator modulates the linear increments of phase to produce random phase-modulated waveform. The proposed waveform generator requires only one DDS for generating variety of modulated waveforms, while existing designs require separate DDS units for different type of waveforms, and multiple DDS units are required to generate composite waveforms. Therefore, area complexity of existing designs gets multiplied with the number of different types waveforms they generate, while in case of proposed design that remains unchanged. The proposed AWG when mapped on Xilinx Spartan 2E device, consumes 1076 slices and 2016 4-input LUTs. The proposed AWG involves significantly less area and lower latency, with nearly the same throughput compared to the existing CORDIC-based designs
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scale free Hyperbolic cordic processor and its application to waveform generation
IEEE Transactions on Circuits and Systems, 2013Co-Authors: Supriya Aggarwal, P K Meher, Kavita KhareAbstract:This paper presents a novel completely scaling-free CORDIC algorithm in rotation mode for Hyperbolic Trajectory. We use most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iterations. By storing the sinh/cosh Hyperbolic values at octant boundaries in a ROM, we can extend the range of convergence to the entire coordinate space. Based on this, we propose a pipeline Hyperbolic CORDIC processor to implement a direct digital synthesizer (DDS). The DDS is further used to derive an efficient arbitrary waveform generator (AWG), where a pseudo-random number generator modulates the linear increments of phase to produce random phase-modulated waveform. The proposed waveform generator requires only one DDS for generating variety of modulated waveforms, while existing designs require separate DDS units for different type of waveforms, and multiple DDS units are required to generate composite waveforms. Therefore, area complexity of existing designs gets multiplied with the number of different types waveforms they generate, while in case of proposed design that remains unchanged. The proposed AWG when mapped on Xilinx Spartan 2E device, consumes 1076 slices and 2016 4-input LUTs. The proposed AWG involves significantly less area and lower latency, with nearly the same throughput compared to the existing CORDIC-based designs.
Supriya Aggarwal - One of the best experts on this subject based on the ideXlab platform.
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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1 Scale-Free Hyperbolic CORDIC Processor and its Application to Waveform Generation
2016Co-Authors: Supriya Aggarwal, Pramod Meher Senior K. Member, Kavita KhareAbstract:Abstract—This paper presents a novel completely scaling-free CORDIC algorithm in rotation mode for Hyperbolic Trajectory. We use most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iterations. By storing the sinh/cosh Hyperbolic values at octant boundaries in a ROM, we can extend the range of convergence to the entire coordinate space. Based on this, we propose a pipeline Hyperbolic CORDIC processor to implement a direct digital synthesizer (DDS). The DDS is further used to derive an efficient arbitrary waveform generator (AWG), where a pseudo-random number generator modulates the linear increments of phase to produce random phase-modulated waveform. The proposed waveform generator requires only one DDS for generating variety of modulated waveforms, while existing designs require separate DDS units for different type of waveforms, and multiple DDS units are required to generate composite waveforms. Therefore, area complexity of existing designs gets multiplied with the number of different types waveforms they generate, while in case of proposed design that remains unchanged. The proposed AWG when mapped on Xilinx Spartan 2E device, consumes 1076 slices and 2016 4-input LUTs. The proposed AWG involves significantly less area and lower latency, with nearly the same throughput compared to the existing CORDIC-based designs
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scale free Hyperbolic cordic processor and its application to waveform generation
IEEE Transactions on Circuits and Systems, 2013Co-Authors: Supriya Aggarwal, P K Meher, Kavita KhareAbstract:This paper presents a novel completely scaling-free CORDIC algorithm in rotation mode for Hyperbolic Trajectory. We use most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iterations. By storing the sinh/cosh Hyperbolic values at octant boundaries in a ROM, we can extend the range of convergence to the entire coordinate space. Based on this, we propose a pipeline Hyperbolic CORDIC processor to implement a direct digital synthesizer (DDS). The DDS is further used to derive an efficient arbitrary waveform generator (AWG), where a pseudo-random number generator modulates the linear increments of phase to produce random phase-modulated waveform. The proposed waveform generator requires only one DDS for generating variety of modulated waveforms, while existing designs require separate DDS units for different type of waveforms, and multiple DDS units are required to generate composite waveforms. Therefore, area complexity of existing designs gets multiplied with the number of different types waveforms they generate, while in case of proposed design that remains unchanged. The proposed AWG when mapped on Xilinx Spartan 2E device, consumes 1076 slices and 2016 4-input LUTs. The proposed AWG involves significantly less area and lower latency, with nearly the same throughput compared to the existing CORDIC-based designs.
P K Meher - One of the best experts on this subject based on the ideXlab platform.
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scale free Hyperbolic cordic processor and its application to waveform generation
IEEE Transactions on Circuits and Systems, 2013Co-Authors: Supriya Aggarwal, P K Meher, Kavita KhareAbstract:This paper presents a novel completely scaling-free CORDIC algorithm in rotation mode for Hyperbolic Trajectory. We use most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iterations. By storing the sinh/cosh Hyperbolic values at octant boundaries in a ROM, we can extend the range of convergence to the entire coordinate space. Based on this, we propose a pipeline Hyperbolic CORDIC processor to implement a direct digital synthesizer (DDS). The DDS is further used to derive an efficient arbitrary waveform generator (AWG), where a pseudo-random number generator modulates the linear increments of phase to produce random phase-modulated waveform. The proposed waveform generator requires only one DDS for generating variety of modulated waveforms, while existing designs require separate DDS units for different type of waveforms, and multiple DDS units are required to generate composite waveforms. Therefore, area complexity of existing designs gets multiplied with the number of different types waveforms they generate, while in case of proposed design that remains unchanged. The proposed AWG when mapped on Xilinx Spartan 2E device, consumes 1076 slices and 2016 4-input LUTs. The proposed AWG involves significantly less area and lower latency, with nearly the same throughput compared to the existing CORDIC-based designs.
Olivier Lablee - One of the best experts on this subject based on the ideXlab platform.
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semi classical behaviour of schrodinger s dynamics revivals of wave packets on Hyperbolic Trajectory
Asymptotic Analysis, 2011Co-Authors: Olivier LableeAbstract:The aim of this paper is to study the semi-classical behaviour of Schrodinger's dynamics for an one-dimesional quantum Hamiltonian with a classical Hyperbolic Trajectory. As in the regular case (elliptic Trajectory), we prove, that for an initial wave packets localized in energy, the dynamics follows the classical motion during short time. And, for large time, a new period for the dynamics appears : the wave packets revivals.
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semi classical behaviour of schr odinger s dynamics revivals of wave packets on Hyperbolic Trajectory
arXiv: Spectral Theory, 2010Co-Authors: Olivier LableeAbstract:The aim of this paper is to study the semi-classical behaviour of Schr\"odinger's dynamics for an one-dimesional quantum Hamiltonian with a classical Hyperbolic Trajectory. As in the regular case (elliptic Trajectory), we prove, that for an initial wave packets localized in energy, the dynamics follows the classical motion during short time. And, for large time, a new period for the dynamics appears : the wave packets revivals.
Stephen Wiggins - One of the best experts on this subject based on the ideXlab platform.
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Lagrangian descriptors and glider path
2019Co-Authors: Víctor José García Garrido, Ana Mancho, Stephen Wiggins, Jezabel CurbeloAbstract:Glider path and Eulerian velocity fields in the neighborhood of a Hyperbolic Trajectory highlighted by the function M. a) 19th June 2016. b) 20th June 2016. c) 23rd June 2016.
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Figure 2, Paths in a turbulent ocean
2019Co-Authors: Ana Mancho, Víctor José García Garrido, Jezabel Curbelo, Stephen WigginsAbstract:a) A Hyperbolic Trajectory in a vector field. Particles at successive times evolve by approaching the Hyperbolic point along the stable direction (blue) and getting away from it along the unstable direction (red). Green blobs that represent particle ensembles illustrate this behavior; b) Visualization of a Hyperbolic point by means of Lagrangian Descriptors (also known as function M) evaluated on a time dependent velocity field. The current field is drawn with black arrows.
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distinguished Hyperbolic trajectories in time dependent fluid flows analytical and computational approach for velocity fields defined as data sets
Nonlinear Processes in Geophysics, 2002Co-Authors: Kayo Ide, Des Small, Stephen WigginsAbstract:Abstract. In this paper we develop analytical and numerical methods for finding special Hyperbolic trajectories that govern geometry of Lagrangian structures in time-dependent vector fields. The vector fields (or velocity fields) may have arbitrary time dependence and be realized only as data sets over finite time intervals, where space and time are discretized. While the notion of a Hyperbolic Trajectory is central to dynamical systems theory, much of the theoretical developments for Lagrangian transport proceed under the assumption that such a special Hyperbolic Trajectory exists. This brings in new mathematical issues that must be addressed in order for Lagrangian transport theory to be applicable in practice, i.e. how to determine whether or not such a Trajectory exists and, if it does exist, how to identify it in a sequence of instantaneous velocity fields. We address these issues by developing the notion of a distinguished Hyperbolic Trajectory (DHT). We develop an existence criteria for certain classes of DHTs in general time-dependent velocity fields, based on the time evolution of Eulerian structures that are observed in individual instantaneous fields over the entire time interval of the data set. We demonstrate the concept of DHTs in inhomogeneous (or "forced") time-dependent linear systems and develop a theory and analytical formula for computing DHTs. Throughout this work the notion of linearization is very important. This is not surprising since Hyperbolicity is a "linearized" notion. To extend the analytical formula to more general nonlinear time-dependent velocity fields, we develop a series of coordinate transforms including a type of linearization that is not typically used in dynamical systems theory. We refer to it as Eulerian linearization, which is related to the frame independence of DHTs, as opposed to the Lagrangian linearization, which is typical in dynamical systems theory, which is used in the computation of Lyapunov exponents. We present the numerical implementation of our method which can be applied to the velocity field given as a data set. The main innovation of our method is that it provides an approximation to the DHT for the entire time-interval of the data set. This offers a great advantage over the conventional methods that require certain regions to converge to the DHT in the appropriate direction of time and hence much of the data at the beginning and end of the time interval is lost.