A signal processing scheme to improve the performance of some sonar systems

1998 ◽  
Vol 16 (1) ◽  
pp. 17-20
Author(s):  
Xu Lu-fen
Keyword(s):  
Signal Processing ◽  
Processing Scheme ◽  
Sonar Systems

Low coherence, interferometric fibre optic vibrometer using novel optical signal processing scheme

1991 ◽  
Vol 27 (18) ◽  
pp. 1658 ◽  
Author(s):  
K. Weir ◽  
W.J.O. Boyle ◽  
A.W. Palmer ◽  
K.T.V. Grattan ◽  
B.T. Meggitt
Keyword(s):  
Signal Processing ◽  
Optical Signal Processing ◽  
Optical Signal ◽  
Fibre Optic ◽  
Processing Scheme ◽  
Low Coherence

scholarly journals Validation of a new signal processing scheme for the MST radar at Aberystwyth

2008 ◽  
Vol 26 (11) ◽  
pp. 3253-3268 ◽  
Author(s):  
D. A. Hooper ◽  
J. Nash ◽  
T. Oakley ◽  
M. Turp
Keyword(s):  
Signal Processing ◽  
Measurement Error ◽  
Gravity Wave ◽  
Wave Activity ◽  
Horizontal Wind ◽  
Time Averaging ◽  
Random Measurement Error ◽  
Processing Scheme ◽  
Random Measurement ◽  
Short Period

Abstract. This paper describes a new signal processing scheme for the 46.5 MHz Doppler Beam Swinging wind-profiling radar at Aberystwyth, in the UK. Although the techniques used are similar to those already described in literature – i.e. the identification of multiple signal components within each spectrum and the use of radial- and time-continuity algorithms for quality-control purposes – it is shown that they must be adapted for the specific meteorological environment above Aberystwyth. In particular they need to take into account the three primary causes of unwanted signals: ground clutter, interference, and Rayleigh scatter from hydrometeors under stratiform precipitation conditions. Attention is also paid to the fact that short-period gravity-wave activity can lead to an invalidation of the fundamental assumption of the wind field remaining stationary over the temporal and spatial scales encompassed by a cycle of observation. Methods of identifying and accounting for such conditions are described. The random measurement error associated with horizontal wind components is estimated to be 3.0–4.0 m s−1 for single cycle data. This reduces to 2.0–3.0 m s−1 for data averaged over 30 min. The random measurement error associated with vertical wind components is estimated to be 0.2–0.3 m s−1. This cannot be reduced by time-averaging as significant natural variability is expected over intervals of just a few minutes under conditions of short-period gravity-wave activity.

scholarly journals Noisy Reverberation Suppression Using AdaBoost Based EMD in Underwater Scenario

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kusma Kumari Cheepurupalli ◽  
Raja Rajeswari Konduri
Keyword(s):  
Signal Processing ◽  
Acoustic Signal ◽  
Probability Of Detection ◽  
Chirp Signal ◽  
Processing Scheme ◽  
Adaptive Boosting ◽  
Mode Decomposition ◽  
Crucial Problem ◽  
Filtering Technique ◽  
Simulation Results

Reverberation suppression is a crucial problem in sonar communications. If the acoustic signal is radiated in the water as medium then the degradation is caused due to the reflection coming from surface, bottom, and volume of water. This paper presents a novel signal processing scheme that offers an improved solution in reducing the effect of interference caused due to reverberation. It is based on the combination of empirical mode decomposition (EMD) and adaptive boosting (AdaBoost) techniques. AdaBoost based EMD filtering technique is used for reverberation corrupted chirp signal to decrease the noisy components present in the received signal. An improvement in the probability of detection is achieved using the proposed algorithm. The simulation results are obtained for various reverberation times at various SNR levels.

scholarly journals On signal processing scheme based on network coding in relay-assisted D2D systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Bo Li ◽  
Qiuming Zhao ◽  
Ruofei Ma ◽  
Hongjuan Yang ◽  
Gongliang Liu ◽  
...  
Keyword(s):  
Signal Processing ◽  
Network Coding ◽  
Processing Scheme

scholarly journals Digital Signal Processing Applied to the Modernization Of Polish Navy Sonars

2014 ◽  
Vol 21 (2) ◽  
pp. 65-75 ◽  
Author(s):  
Jacek Marszal
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Digital Signal ◽  
Electronic Systems ◽  
Ultrasound Transducers ◽  
Processing Methods ◽  
Complete Replacement ◽  
University Of Technology ◽  
Sonar Systems ◽  
Signal Processing Methods

AbstractThe article presents the equipment and digital signal processing methods used for modernizing the Polish Navy’s sonars. With the rapid advancement of electronic technologies and digital signal processing methods, electronic systems, including sonars, become obsolete very quickly. In the late 1990s a team of researchers of the Department of Marine Electronics Systems, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, began work on modernizing existing sonar systems for the Polish Navy. As part of the effort, a methodology of sonar modernization was implemented involving a complete replacement of existing electronic components with newly designed ones by using bespoke systems and methods of digital signal processing. Large and expensive systems of ultrasound transducers and their dipping and stabilisation systems underwent necessary repairs but were otherwise left unchanged. As a result, between 2001 and 2014 the Gdansk University of Technology helped to modernize 30 sonars of different types.

scholarly journals Joint Time-Frequency Signal Processing Scheme in Forward Scattering Radar with a Rotational Transmitter

2016 ◽  
Vol 8 (12) ◽  
pp. 1028 ◽  
Author(s):  
Raja Raja Abdullah ◽  
Azizi Mohd Ali ◽  
Mohd Rasid ◽  
Nur Abdul Rashid ◽  
Asem Ahmad Salah ◽  
...  
Keyword(s):  
Signal Processing ◽  
Forward Scattering ◽  
Frequency Signal ◽  
Processing Scheme ◽  
Time Frequency

ACHIEVING A LINEAR DOSE RATE RESPONSE IN PULSE-MODE SILICON PHOTODIODE SCINTILLATION DETECTORS OVER A WIDE RANGE OF EXCITATIONS

2014 ◽  
Vol 27 ◽  
pp. 1460136
Author(s):  
LEWIS CARROLL
Keyword(s):  
Signal Processing ◽  
Dose Rate ◽  
Pulse Generator ◽  
Current Mode ◽  
Pulse Mode ◽  
Radioactive Material ◽  
Activity Levels ◽  
Silicon Photodiode ◽  
Processing Scheme ◽  
Wide Range

We are developing a new dose calibrator for nuclear pharmacies that can measure radioactivity in a vial or syringe without handling it directly or removing it from its transport shield “pig”. The calibrator's detector comprises twin opposing scintillating crystals coupled to Si photodiodes and current-amplifying trans-resistance amplifiers. Such a scheme is inherently linear with respect to dose rate over a wide range of radiation intensities, but accuracy at low activity levels may be impaired, beyond the effects of meager photon statistics, by baseline fluctuation and drift inevitably present in high-gain, current-mode photodiode amplifiers. The work described here is motivated by our desire to enhance accuracy at low excitations while maintaining linearity at high excitations. Thus, we are also evaluating a novel “pulse-mode” analog signal processing scheme that employs a linear threshold discriminator to virtually eliminate baseline fluctuation and drift. We will show the results of a side-by-side comparison of current-mode versus pulse-mode signal processing schemes, including perturbing factors affecting linearity and accuracy at very low and very high excitations. Bench testing over a wide range of excitations is done using a Poisson random pulse generator plus an LED light source to simulate excitations up to ∼106 detected counts per second without the need to handle and store large amounts of radioactive material.

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