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Explosive charges are widely used in underwater acoustics experiments because it has wide bandwidth and high source level. the received signals are the shock wave and followed by a series of bubble pulses, which seriously affect the observation and applications of the signal. But for the shallow water waveguides, the bubble pulses could be seen as anther “signal”. In this paper, we treat the first...
This paper proposes a method to detect photon counts from a commercial off-the-shelf SPAD array. Experiments show that using this method the sensitivity of a VLC receiver that incorporates this SPAD array approaches the limit set by Poisson noise.
A novel multi-dimensional noise-shaping method is proposed to extend Δ-Σ modulation to the two-dimensional (2-D) (space, time) case. It uses spatial oversampling to provide another degree of freedom for ADC designers to shape quantization noise when temporal oversampling is limited. The method uses lossless discrete integrators (LDIs) to implement spatial integrators and is suitable for use in microwave...
In this paper, we describe the development of a new L-band (1.4 GHz) Cryogenic Phased Array Feed (PAF) system, referred to as the GBT2 array. Results from initial measurements made with the GBT2 array are also presented. The PAF was developed for the Green Bank Telescope (GBT) as part of the Focal L-band Array for the GBT (FLAG) project. During the first stage of the development work (Phase I), a...
The Local Rarest Bundle First (LRBF) and Local Rarest Generation First (LRGF), content distribution strategies for delayed-tolerance networks (DTNs), reach high delivery rate in the vehicular ad-hoc networks (VANETs), where intermittent connectivity due to permanent network fragmentation and node mobility are main challenges. However, in order to achieve a high delivery rate, both strategies require...
Clutter heterogeneity caused by cultivation variation of the terrain properties degrades STAP detection performance. In recent years, a priori knowledge sources has been used directly and indirectly for STAP performance improvement. Monostatic radar systems are typically considered, but in the bistatic case, strong clutter non-stationarity introduced by the geometry makes convetional STAP not possible...
This article presents a near-field magnetic multi-input multi-output (MIMO) communication system test bed using software defined radio (SDR). We propose a heterogeneous multi-pole loop antenna array for near-field magnetic MIMO system. In this paper, we show improved performance of the proposed near-field magnetic MIMO communication system over a conventional magnetic MIMO system employing a circular...
Steganography is the classical technique of securing the confidential data. The data is hidden in an object called cover medium. The encoder (sender) and the decoder (receiver) only have the knowledge of secret data hidden in the cover object. An image is a cover object that hides the secret data. DNA is another cover object which has a huge data storage capacity and it hides a very large secret data...
Antenna calibration is a mandatory requirement to determine the attitude of a multi-antenna receiver. Moreover, knowing the antenna attitude can vastly improve detection and mitigation of spoofers and / or Radio Frequency Interferences (RFIs). In todays receivers the time-varying phase offset introduced by the active elements like amplifiers, downconverters as well as various filters and unequal cable...
This paper explores a 60 GHz phased array system for ultra-high data rate communication in indoor environments. The channel modeling is addressed and the system link budget is calculated. A 16-element phased array system specifications are presented. This paper also presents the design of one of the key blocks — a 5-bit digitally controlled passive phase shifter. The switch-type phase shifter is implemented...
Acoustic telemetry is an essential tool for ecological and behavioral analysis of fish and marine mammals in fresh and sea water. However, the accuracy of acoustic telemetry is a challenging problem in that acoustic detection is affected by various environmental factors that govern sound speed and propagation: density, density stratification, mixing, and the environmental processes that control them...
This paper addresses the problem of blind source enumeration in the colored and unbalanced noise environment, where the number of sources can be equal to or more than the number of observers. In the proposed algorithm, the Gerschgorin Disk Estimator (GDE) is used as the detection rule and fourth-order cumulant of the observed data is used to estimate Gerschgorins radii. Compared with the minimum description...
Appropriate signal model derivation for transmitter and receiver can achieve side lobe reduction in phased array antenna and can also be used to accurately determining direction of arrival (DOA). Dolph-Chebyshev array structure is used for null placing in the antenna radiation pattern. This structure ensures nulls have been placed at proper positions to jam the interferers. For this purpose, interferers...
Space Fence, currently under construction on Kwajalein Atoll, will revolutionize Space Situational Awareness (SSA) using advanced phased array radar technology in two of the largest phased arrays to ever be constructed. Space Fence will provide catalog completeness, accuracy and timeliness with vastly improved performance in Low Earth Orbit (LEO) and capability to support missions in Geosynchronous...
We recently proposed the use of consensus optimization as a viable and effective way to improve the quality of calibration of radio interferometric data. We showed that it is possible to obtain far more accurate calibration solutions and also to distribute the compute load across a network of computers by using this technique. A crucial aspect in any consensus optimization problem is the selection...
This paper introduces the Array-based Compressed sensing Receiver Architecture (ACRA). ACRA allows digital receiver arrays to operate at dramatically larger instantaneous bandwidths by sampling the signals from different array elements at different sub-Nyquist sampling rates. Signal processing inspired by the sparse fast Fourier transform allows for signal detection, estimation, and angle-of-arrival...
Wireless power transfer (WPT) could revolutionize global transportation and accelerate growth in the Electric Vehicle (EV) market, offering an attractive alternative to cabled charging. Coil misalignment is inevitable due to driver parking behaviour and has a detrimental effect on power transfer efficiency (PTE). This paper proposes a novel coil design and adaptive hardware to improve PTE in magnetic...
This paper presents a novel and unique concept of color cell (CC) for bidirectional visible light communications (VLCs). The proposed CC based VLC provides a comprehensive and practical solution to the issues associated with full coverage and user mobility in a comparatively larger indoor environment. In the CC scheme, color filter array (CFA) is utilized at the receiver end with a novel user mobility...
Nowadays, ultrasonic images are widely synthesized during non destructive testing of materials in order to improve internal defects detection. However, when large structures are inspected, too useless images are stored and processed. This article describes a proposed method that reduces the data storage to only those regarding a detected defect. Data selection is performed in real time by exploiting...
Digital array radars (DAR) with element-level digital transmission and reception present new opportunities for more advanced radar functionality and performance. In order to reduce RF front-end complexity while also reducing the need for high sample rates, the analog IQ demodulation receiver, or homodyne, is proposed so that only a single local oscillator (LO) is needed per element. An important homodyne...
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