Analysis and Design of a Self-Charged Crystal Oscillator with Pulse Regulating Feedback Loop

2020 ◽  
Author(s):  
Hsiang-Chun Cheng ◽  
Yu-Hong Yang ◽  
Tai-Cheng Lee
Keyword(s):  
Feedback Loop ◽  
Crystal Oscillator ◽  
Analysis And Design

scholarly journals Optimal On-Off Attitude Control for the Brazilian Multimission Platform Satellite

2009 ◽  
Vol 2009 ◽  
pp. 1-17 ◽  
Author(s):  
Gilberto Arantes ◽  
Luiz S. Martins-Filho ◽  
Adrielle C. Santana
Keyword(s):  
Control Systems ◽  
Attitude Control ◽  
Feedback Loop ◽  
Pulse Frequency ◽  
Pulse Mode ◽  
Control Law ◽  
Continuous Control ◽  
Analysis And Design ◽  
First Order ◽  
Propellant Consumption

This work deals with the analysis and design of a reaction thruster attitude control for the Brazilian Multimission platform satellite. The three-axis attitude control systems are activated in pulse mode. Consequently, a modulation of the torque command is compelling in order to avoid high nonlinear control action. This work considers the Pulse-Width Pulse-Frequency (PWPF) modulator which is composed of a Schmidt trigger, a first-order filter, and a feedback loop. PWPF modulator holds several advantages over classical bang-bang controllers such as close to linear operation, high accuracy, and reduced propellant consumption. The Linear Gaussian Quadratic (LQG) technique is used to synthesize the control law during stabilization mode and the modulator is used to modulate the continuous control signal to discrete one. Numerical simulations are used to analyze the performance of the attitude control. The LQG/PWPF approach achieves good stabilization-mode requirements as disturbances rejection and regulation performance.

Analysis and design of quickly starting crystal oscillator

2015 ◽  
Author(s):  
Weiguo Zheng ◽  
Min Cai ◽  
Xiaoyong He ◽  
Ken Xu ◽  
Zhijian Chen
Keyword(s):  
Crystal Oscillator ◽  
Analysis And Design

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

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