Generation and cancellation of second-order harmonic distortion in analog optical systems by interferometric FM-AM conversion

1990 ◽  
Vol 2 (7) ◽  
pp. 519-521 ◽  
Author(s):  
A. Lidgard ◽  
N.A. Olsson
Keyword(s):  
Harmonic Distortion ◽  
Second Order ◽  
Optical Systems

The imaging properties of electron beams in arbitrary static electromagnetic fields

1952 ◽  
Vol 245 (894) ◽  
pp. 155-187 ◽  
Keyword(s):  
Variational Equation ◽  
Chromatic Aberration ◽  
Relativistic Correction ◽  
Zero Order ◽  
Second Order ◽  
Optical Systems ◽  
Characteristic Functions ◽  
Tensor Calculus ◽  
Paraxial Ray ◽  
Imaging Properties

Electron-optical systems with curved axes—such as mass spectrographs and certain beta-ray spectrometers—have long been in practical use, but there has been available no complete theory of the aberrations of such systems. It is the object of the present paper to construct such a theory and to demonstrate, by an example, its application to practical problems. An appropriate co-ordinate system is set up by means of a ray-axis together with its normal and binormal. The electric and magnetic fields are then investigated with the help of tensor calculus; the variational principle of electron optics is also put into tensor form. The integrand of the variational equation may be separated into a series of polynomials, one of which determines the paraxial imaging properties of the system and the rest of which determine the aberrations. The condition is established for which, upon an appropriate transformation, either of the paraxial ray equations contains only one off-axis co-ordinate. Subsequent investigations are restricted to systems, which are termed ‘orthogonal’, for which this condition is satisfied. It is shown that, in a certain sense, no orthogonal electron-optical system can be wholly divergent. The second-order aberration and the zero-order and paraxial chromatic aberrations are then investigated by the method of perturbation characteristic functions. All formulae are given in their relativistic forms but their non-relativistic forms are indicated; formulae are therefore given for the calculation of the zero-order and paraxial relativistic correction. It is indicated to what extent one forfeits control over the second-order aberration—and hence over the paraxial chromatic aberration also—by specifying that the paraxial behaviour of rays should be Gaussian. As an example, the imaging properties of a helical beam moving in the field of a pair of coaxial cylindrical electrodes are calculated. There is also an appendix which gives formulae for the effect upon aberrations of a change in the aperture position.

The geometrical aberrations of general electron optical systems II. The primary (third order) aberrations of orthogonal systems, and the secondary (fifth order) aberrations of round systems

1965 ◽  
Vol 257 (1086) ◽  
pp. 523-552 ◽  
Keyword(s):  
Second Order ◽  
Order Perturbation ◽  
Optical Systems ◽  
Characteristic Functions ◽  
Electron Optics ◽  
Third Order ◽  
Variation Of Parameters ◽  
General Kind ◽  
Fifth Order ◽  
Orthogonal Systems

The theory of characteristic functions, developed by Sturrock for electron optics, is used to calculate the primary aberrations of rectilinear orthogonal systems of the most general kind. In the second part, the secondary aberrations of round systems are calculated with the aid of Sturrock’s second-order perturbation characteristic functions. A proof of the equivalence of the aberration formulae obtained by Melkich, using the variation of parameters method, and those obtained below is offered in an appendix.

scholarly journals Higher Control Scheme Using Neural Second Order Sliding Mode and ANFIS-SVM strategy for a DFIG-Based Wind Turbine

2019 ◽  
Vol 8 (2) ◽  
pp. 17
Author(s):  
Habib Benbouhenni ◽  
Zinelaabidine Boudjema ◽  
Abdelkader Belaidi
Keyword(s):  
Wind Turbine ◽  
Fuzzy Inference ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Harmonic Distortion ◽  
Second Order ◽  
Inference System ◽  
Wind Turbine System ◽  
Control Scheme ◽  
Second Order Sliding Mode

In this paper, we propose an advanced control scheme using neural second order sliding mode (NSOSMC) and adaptive neuro-fuzzy inference system space vector modulation (ANFIS-SVM) strategy for a doubly fed induction generator (DFIG) integrated into a wind turbine system (WTS). The used hybrid control system composed of artificial intelligence techniques and second-order sliding mode applied to ensure better powers performances provided by the WTS. The obtained simulation results showed that the proposed control structure has active and reactive powers with low ripples and low stator current harmonic distortion.

A Column-Row-Parallel Ultrasound Imaging Architecture for 3-D Plane-Wave Imaging and Tx Second-Order Harmonic Distortion Reduction

2018 ◽  
Vol 65 (5) ◽  
pp. 828-843 ◽  
Author(s):  
Kailiang Chen ◽  
Byung Chul Lee ◽  
Kai E. Thomenius ◽  
Butrus T. Khuri-Yakub ◽  
Hae-Seung Lee ◽  
...  
Keyword(s):  
Plane Wave ◽  
Ultrasound Imaging ◽  
Harmonic Distortion ◽  
Second Order ◽  
Wave Imaging ◽  
Distortion Reduction
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