scholarly journals Compact closed‐loop resonator filters with wide spurious free band and extended common‐mode noise suppression

2020 ◽  
Vol 14 (9) ◽  
pp. 860-866
Author(s):  
Arcesio Arbelaez ◽  
Jose‐Luis Olvera ◽  
Alonso Corona ◽  
Carlos Saavedra
Keyword(s):  
Closed Loop ◽  
Noise Suppression ◽  
Common Mode ◽  
Free Band ◽  
Resonator Filters

Signals and noise in the elasmobranch electrosensory system

1999 ◽  
Vol 202 (10) ◽  
pp. 1349-1355 ◽  
Author(s):  
J.C. Montgomery ◽  
D. Bodznick
Keyword(s):  
Direct Current ◽  
Noise Suppression ◽  
Receptive Fields ◽  
Sensory System ◽  
Mate Recognition ◽  
Common Mode ◽  
Central Processing ◽  
Temporal Properties ◽  
Efferent Neurons ◽  
Bioelectric Fields

Analyzing signal and noise for any sensory system requires an appreciation of the biological and physical milieu of the animal. Behavioral studies show that elasmobranchs use their electrosensory systems extensively for prey detection, but also for mate recognition and possibly for navigation. These biologically important signals are detected against a background of self-generated bioelectric fields. Noise-suppression mechanisms can be recognized at a number of different levels: behavior, receptor anatomy and physiology, and at the early stages of sensory processing. The peripheral filters and receptor characteristics provide a detector with permissive temporal properties but restrictive spatial characteristics. Biologically important signals probably cover the range from direct current to 10 Hz, whereas the bandwidth of the receptors is more like 0.1-10 Hz. This degree of alternating current coupling overcomes significant noise problems while still allowing the animal to detect external direct current signals by its own movement. Self-generated bioelectric fields modulated by breathing movement have similar temporal characteristics to important external signals and produce very strong modulation of electrosensory afferents. This sensory reafference is essentially similar, or common-mode, across all afferent fibers. The principal electrosensory neurons (ascending efferent neurons; AENs) of the dorsal octavolateralis nucleus show a greatly reduced response to common-mode signals. This suppression is mediated by the balanced excitatory and inhibitory components of their spatial receptive fields. The receptive field characteristics of AENs determine the information extracted from external stimuli for further central processing.

Common-Mode Noise Suppression Technique in Interferometric Fiber-Optic Sensors

2019 ◽  
Vol 37 (21) ◽  
pp. 5619-5627 ◽  
Author(s):  
Fei Liu ◽  
Shangran Xie ◽  
Lijuan Gu ◽  
Xiangge He ◽  
Duo Yi ◽  
...  
Keyword(s):  
Noise Suppression ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Common Mode ◽  
Suppression Technique

Enhanced Active Constrained Layer Damping Treatment for Broadband Vibration Suppression

2002 ◽  
Vol 8 (6) ◽  
pp. 777-803 ◽  
Author(s):  
Y. Liu ◽  
K. W. Wang
Keyword(s):  
Closed Loop ◽  
Noise Suppression ◽  
Vibration Suppression ◽  
Wide Frequency Range ◽  
Open Loop ◽  
Loop System ◽  
Constrained Layer Damping ◽  
Edge Elements ◽  
Modal Damping ◽  
Active Constrained Layer

In this paper, the Enhanced Active Constrained Layer (EACL) treatment is investigated for broadband damping augmentations on beam structures. The EACL concept was originally proposed to improve the damping performance of the Active Constrained Layer (ACL) by introducing edge elements at the treatment boundaries. It has been recognized that the edge elements can increase ACL performance by enhancing the direct active authority of the piezoelectric constraining layer. It has also been demonstrated that the edge element stiffness and the host structure strain field have significant influence on the overall closed-loop system damping and its various components: the active damping, the closed-loop passive damping, and the open-loop passive (fail-safe property - without any active action) damping. Through utilizing this finding, the present study explores how the EACL performance can be synthesized for multiple mode broadband applications using symmetric configurations. Although the edge elements will tend to reduce the maximum possible open-loop damping of one (or a few) vibration mode, open-loop damping of the other higher order modes could actually be increased. Moreover, the modal damping reduction in the open-loop system can generally be compensated by the significant increase of the closed-loop damping. In other words, the closed-loop EACL system damping over a wide frequency range can be significant, which makes it attractive for broadband vibration and noise suppression.

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