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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
n-ary ands can be obtained as conjunction of binary ands. AND gate a device that implements the Boolean AND operation. See AND. angle diversity a diversity technique used in radio communications based on receiving a signal over multiple arrival angles. The signal components are typically affected by uncorrelated fading processes and are combined in the receiver to improve performance. The main combining methods are selection diversity, equal gain combining, and maximal ratio combining. angle modulation a type of modulation where either the frequency (FM) or the phase (PM) of a carrier are varied. angle of arrival (AOA) the direction to a source emitting a signal impinging on a sensor array. Also called direction of arrival (DOA). angstrom popular unit not officially recognized as part of the SI unit system. Equal to 10-10 meters. Abbreviated A. Named after Anders Angstrüm (1814-1874). o angular alignment loss the optical power loss in an optical connection between two optical fibers, between an optical source and a fiber, or between an optical fiber and a detector caused by the angular misalignment of the axes of the source and fiber, the two fibers, or the fiber and detector. angular frequency the rate of change of the phase of a wave in radians per second.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
In angle modulation, the message signal is transmitted in the “angle” (i.e., frequency or phase) of the carrier signal as opposed to its amplitude. There are two main angle modulation schemes, namely, frequency modulation (FM) and phase modulation (PM). The modulated signal is given by u(t)=Accos2πfct+ϕ(t)
Modulation Techniques
Published in Bassem R. Mahafza, Introduction to Radar Analysis, 2017
Phase or frequency modulation techniques are denoted as angle modulation since the phase angle of the modulated carrier signal conveys the message signal. In general, angle modulation is referred to as nonlinear modulation technique since a linear change in phase or frequency occurs as a result of the modulation process. The channel introduces zero mean Gaussian noise to the transmitted signal. For this purpose, the signal y(t) can be written as () y(t)=x(t)+n(t)
Power system optimization approach to mitigate voltage instability issues: A review
Published in Cogent Engineering, 2023
Samson Ademola Adegoke, Yanxia Sun
Furthermore, angle modulation PSO (AMPSO) is another modified form of binary PSO, used to produce a string bit to solve original higher dimensional problems. Using direct mapping back to the binary space by an angle of modulation, the higher dimensional problem is minimized to the four-dimensional problems in continuous spaces (Mohais et al., 2005). The genetic BPSO model was reported by Peer et al. (2003) without fixing the sizes of the swarms. An algorithm comprising two forms, including death and birth, was used to modulate the swarm dynamically. It was observed that death and birth rate changed with time; the BPSO model allowed oscillations in the swarm sizes. Naturally, it is social behaviors were ascribed to the intelligent animal (Peer et al., 2003). The binary PSO enhancement was reported by (Kadirkamanathan et al., 2006), who used the phenotype-genotype methods and gave a mutation operation of GA to BPSO (Kadirkamanathan et al., 2006). Beheshti and Shamsuddin (2015) reported a memetic BPSO with a hybrid global and local search in BPSO. The topology of binary hybrid PSO has been used to solve the problem of optimization in a binary search space (Beheshti & Shamsuddin, 2015).
Visualizing local bending of lattice planes by extending two-azimuth synchrotron X-ray diffraction datasets to asymmetric reflection
Published in Science and Technology of Advanced Materials: Methods, 2023
Our group has intensively studied GaN substrates and their homoepitaxial thin films using synchrotron X-ray diffraction [21–29]. While all these studies have used synchrotron X-ray-based RCI, we applied a modified RCI method we proposed to the following: lattice-plane orientation mapping of homoepitaxial GaN (0001) thin films grown on a 2-inch whole wafer [22];visualization of crystal perfection and the lattice-plane shape of a 4-inch whole GaN wafer [23];evaluation of anisotropic mosaicity and visualization of lattice-plane twisting of an m-plane GaN homoepitaxial layer [25];evaluation of lattice-plane bending angle modulation of magnesium-doped GaN homoepitaxial films [26];the local lattice-plane shape of a 6-inch whole GaN wafer [29].
Simulation Study on On-Line MTPA/MTPV Trajectory Tracking in PMSMs with Power Management
Published in Electric Power Components and Systems, 2020
Haibo Li, Yi Qian, Sohrab Asgarpoor, Hamid Sharif
The proposed method for on-line tracking of PMSM optimal current trajectory is flexible to tune in a real-time manner with additional constraints and system parameter variations. For example, the machine current limiting in electric drive systems will enhance components protection and facilitate system design [30], and is highly desirable in addition to optimal current trajectory tracking. When a maximum machine current Im,max is considered, a Te* limiting block is needed to achieve the machine and inverter overcurrent regulation, as shown in Figure 9. Specifically, the calculated current commands from MTPA and MTPV blocks are used to check if the machine current will exceed Im,max. If Im,max is exceeded, new current commands must be generated to meet the overcurrent regulation requirement. A maximum torque Tm,max under Im,max can be found based on machine current angle modulation through sweeping the PMSM current angle α, which returns id and iq in each step as