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Distributed Multi-Antenna SAR Time and Phase Synchronization
Published in Wen-Qin Wang, Multi-Antenna Synthetic Aperture Radar, 2017
Distributed multi-antenna SAR systems is subject to time and phase synchronization problem that is not encountered in colocated multi-antennas SAR systems. In this chapter, we analyzed the impacts of time and phase synchronization errors on distributed multi-antenna SAR imaging by using the developed statistical phase noise model. This model can predict time-domain phase errors in practical oscillators. Since effective time and phase synchronization compensation must be performed for current radar hardware systems, we introduced four types of time and phase synchronization methods. They are direct-path signal-based time and phase synchronization, GPS-based time and phase synchronization, synchronization link-based phase synchronization, and transponder-based phase synchronization.
Binding Problem
Published in Kaushik Majumdar, A Brief Survey of Quantitative EEG, 2017
The idea of phase synchronization is about four centuries old. It was first described by Christian Huygens for two pendulums oscillating simultaneously. The notion of phase synchronization that was conceived was essentially phase synchronization between two sinusoidal signals. Fourier transformation–based phase synchronization captures the geometric flavor of that classical notion. Also, unlike the previous two measures, the Fourier transform–based phase synchronization measure works in a frequency domain rather than a time domain.
Proprioceptive feedback design for gait synchronization in collective undulatory robots
Published in Advanced Robotics, 2022
Zhuonan Hao, Wei Zhou, Nick Gravish
When multiple limit cycle oscillators are coupled, the neutral stability of the phase variable can lead to synchronization phenomena [24]. Phase synchronization occurs when oscillators with a common frequency align their phases in often an in-phase, or anti-phase, arrangement. If oscillators have different natural frequencies, in some instances coupling can drive the group to a common oscillatory frequency. The canonical model for such synchronizing systems is the Kuramoto model of synchronization [25] where the phase variables of oscillators are directly coupled. In the appropriate regimes of coupling strength and connectivity, this system will display a wide range of phase and frequency synchronization behavior. The Kuramoto system has been extensively studied and there are many reviews of the system phenomenology [26]. However, we note that a critical component of synchronization in the Kuramoto system is the explicit coupling between oscillator phases. Oscillator i must have information about oscillator j to determine the relative phase difference. This is in contrast to the method we will present in the next section which does not rely on shared information across oscillators.
Projective synchronization via feedback controller of fractional-order chaotic systems
Published in International Journal of Modelling and Simulation, 2020
Ayub Khan, Muzaffar Ahmad Bhat
Since Pecora and Carroll (1990) have proposed chaos synchronization, synchronization has become a sultry topic in the fields of neural networks and complex networks. Up to now, there are many kinds of synchronization, such as complete synchronization, anti-synchronization, generalized synchronization, projective synchronization, phase synchronization, and lag synchronization. As pointed out in Wang and He (2008), projective synchronization can acquire rapid communication with its proportional aspect. Due to the tremendous applications over the last two decades, in the field of engineering and science [13,14], more and more attention has been diverted towards the behaviour of chaotic systems and their synchronization. Many synchronization strategies have been approached such as complete synchronization, anti-synchronization, phase synchronization, projective synchronization, and hybrid synchronization. Among all, projective synchronization is one of the particular types of synchronization which has been suggested by Mainieri and Rehacek [15]. A drive (master) and response (slave) systems could be synchronized with the help of projective synchronization up to a scaling factor, which can be used to widen binary digital to M-nary digital communication for obtaining rapid communication [15,16]. Many synchronization schemes have been previously applied for fractional-order chaotic systems [7–10,15–18] which have concentrated on the fractional-order chaotic systems with fractional order , but there are so many chaotic systems in the real world having fractional order which is greater than one, for example, heat conduction equation with fractional time [19], the fractional telegraph equation [20], the fractional reaction diffusion system with time [21], diffusion wave equation with fractional order [22], the fractional-order space–time diffusion equation [23], the supper diffusion systems [24], and so on, but the phenomenon of chaos was not considered in [19–24]. Meanwhile, Jhaung and Ge based on numerical simulations described some conclusions on the synchronization of the rotational mechanical system with fractional order .