Digital time delay network for an active underwater acoustic coating

1993 ◽  
Vol 93 (3) ◽  
pp. 1613-1619 ◽  
Author(s):  
Thomas R. Howarth ◽  
Xiaoqi Bao ◽  
Robert Moser ◽  
Vijay K. Varadan ◽  
Vasundara V. Varadan
Keyword(s):  
Time Delay ◽  
Underwater Acoustic ◽  
Digital Time

Digital time delay network for active underwater acoustic coating

1991 ◽  
Vol 89 (4B) ◽  
pp. 1915-1915
Author(s):  
Thomas R. Howarth ◽  
Xiaoqi Bao ◽  
Vijay K. Varadan ◽  
Vasundara V. Varadan
Keyword(s):  
Time Delay ◽  
Underwater Acoustic ◽  
Digital Time

Digital time‐delay beamformer for sonar systems

1981 ◽  
Vol 70 (6) ◽  
pp. 1811-1811
Author(s):  
Adrian van’t Hullenaar
Keyword(s):  
Time Delay ◽  
Sonar Systems ◽  
Digital Time

scholarly journals Underwater Acoustic Time Delay Estimation Based on Envelope Differences of Correlation Functions

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1259 ◽  
Author(s):  
Guodong Li ◽  
Jinsong Wu ◽  
Taolin Tang ◽  
Zhixin Chen ◽  
Jun Chen ◽  
...  
Keyword(s):  
Time Delay ◽  
Correlation Functions ◽  
Estimation Method ◽  
Digital Signal ◽  
Low Complexity ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Estimation Errors ◽  
Underwater Acoustic ◽  
Amplitude Fluctuations

This paper proposes underwater acoustic time delay estimation based on the envelope differences of correlation functions (EDCF), which mitigates the delay estimation errors introduced by the amplitude fluctuations of the correlation function envelopes in the traditional correlation methods (CM). The performance of the proposed delay estimation method under different time values was analyzed, and the optimal difference time values are given. To overcome the influences of digital signal sampling intervals on time delay estimation, a digital time delay estimation approach with low complexity and high accuracy is proposed. The performance of the proposed time delay estimation was analyzed in underwater multipath channels. Finally, the accuracy of the delay estimation using this proposed method was demonstrated by experiments.

Implementation of chaotic circuits with a digital time-delay block

2011 ◽  
Vol 67 (1) ◽  
pp. 345-355 ◽  
Author(s):  
Viet-Thanh Pham ◽  
Luigi Fortuna ◽  
Mattia Frasca
Keyword(s):  
Time Delay ◽  
Chaotic Circuits ◽  
Digital Time

Efficient chroma subsampling strategy for compressing digital time delay integration mosaic video sequences in H.264/AVC

2011 ◽  
Vol 20 (2) ◽  
pp. 023011 ◽  
Author(s):  
Kuo-Liang Chung ◽  
Wei-Jen Yang ◽  
Chyou-Hwa Chen ◽  
Hong-Yuan Mark Liao ◽  
Sheng-Mao Zeng
Keyword(s):  
Time Delay ◽  
Video Sequences ◽  
Digital Time ◽  
Time Delay Integration

Dynamic Analysis and Control of High Speed and High Precision Active Magnetic Bearings

1992 ◽  
Vol 114 (4) ◽  
pp. 623-633 ◽  
Author(s):  
K. Youcef-Toumi ◽  
S. Reddy
Keyword(s):  
Time Delay ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Successful Operation ◽  
Highly Nonlinear ◽  
Wide Range ◽  
And Control ◽  
Digital Time

The successful operation of actively controlled magnetic bearings depends greatly on the electromechanical design and control system design. The function of the controller is to maintain bearing performance in the face of system dynamic variations and unpredictable disturbances. The plant considered here is the rotor and magnetic bearing assembly of a test apparatus. The plant dynamics consisting of actuator dynamics, rigid rotor dynamics and flexibility effects are described. Various components of the system are identified and their corresponding linearized theoretical models are validated experimentally. Tests are also run to identify the coupling effects and flexibility modes. The highly nonlinear behavior of the magnetic bearings in addition to the inherent instability of such a system makes the controller design complex. A digital Time Delay Controller is designed and its effectiveness evaluated using several simulations based on linear and nonlinear models for the bearing including bending mode effects. This controller is implemented as an alternative to an existing linear analog compensator. Several experiments are conducted with each controller for spinning and nonspinning conditions. These include time responses, closed loop frequency responses and disturbance rejection responses. The experimental results and comparisons between those of a digital Time Delay Controller and an analog compensator indicate that the Time Delay Controller has impressive static and dynamic stiffness characteristics for the prototype considered. The Time Delay Controller also maintains almost the same dynamic behavior over a significantly wide range of rotor speeds.

Research on MAC Protocol for UWA Sensor Network

2013 ◽  
Vol 303-306 ◽  
pp. 236-241
Author(s):  
Wen Zhong Zhu
Keyword(s):  
Time Delay ◽  
Sensor Network ◽  
Mac Protocol ◽  
Propagation Delay ◽  
Spatial Multiplexing ◽  
Mac Protocols ◽  
The Other ◽  
Throughput Performance ◽  
Underwater Acoustic ◽  
Agent Protocol

The characteristics and environment of the underwater acoustic (UWA) sensor network require a MAC protocol to be suitable for the long propagation delay. So we put forward a suitable MAC protocol, referring to the AGENT protocol in this paper. We call this protocol C-AGENT-LPD, which means C-AGENT with Long Propagation Delay. And it makes full use of the spatial multiplexing of the UWA channel. Through the simulations, we can see that the protocol has better time delay and throughput performance than the other two MAC protocols.

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