The integrated optic interface reported in this paper is designed to provide the capability of wideband analogue channel and bidirectional digital signal distribution over a single optical fibre when operated with sui...
详细信息
The integrated optic interface reported in this paper is designed to provide the capability of wideband analogue channel and bidirectional digital signal distribution over a single optical fibre when operated with suitable equipment. The range of applications based on this technology could be for inter-equipment rack interconnection, cross site links or phased array antenna RF and control/receive data signal distribution. It is the latter application that is specifically reported in this paper and the integrated optic interface has been developed for a phased array antenna signal distribution network. The compact device is for mounting at the sub-array level or within the solid state transmit/receive (T/R) modules located at the array face and the size advantages offered by this optical technology are particularly relevant in this case. Phased array antennas may require typically 10 to many 1000s of T/R modules and the potential low cost and high performance of an optical interface is extremely attractive. In operation the integrated optic interface would route a microwave reference and control signal to the T/R module via an optical fibre splitter network. In the reverse direction the individual digitised receive channels are distributed back to the digital beam forming network for appropriate signalprocessing. The technology used for the manufacture of this integrated optic interface is silica-on-silicon based and the device developed has a number of optical and electronic functions. This includes WDM and thermo-optic tuning capability as well as digital and RF component integration. How these are incorporated into the integrated optic interface with a general description of the manufacturing details are reported in this paper.
Herein, joint space-time multiplexing in a multi carrier multiple input multiple output (MIMO) system is considered. Previous results concerning the spatial multiplexing optimization are used to address the joint prob...
详细信息
Herein, joint space-time multiplexing in a multi carrier multiple input multiple output (MIMO) system is considered. Previous results concerning the spatial multiplexing optimization are used to address the joint problem of carrier assignment and choice of beamforming weights in a multi user MIMO system. For practical reasons, the joint optimization is divided into two parts: subcarrier assignment based on beamformer characteristics to adjust the carrier load, followed by beamforming optimization with subcarrier reassignment. The goal is to minimize total downlink transmit power while keeping the fixed user data rates. The proposed multiplexing scheme is evaluated on a number of numerical examples.
Time delay estimation arises in many applications in which a multipath channel has to be identified using pulses transmitted through the medium. Various approaches have been proposed in the literature to identify the ...
详细信息
ISBN:
(纸本)9781424451791;9781424451807
Time delay estimation arises in many applications in which a multipath channel has to be identified using pulses transmitted through the medium. Various approaches have been proposed in the literature to identify the time delays of the multipath components. However, these methods require high sampling rates. In this paper, we develop a unified approach to time delay estimation from low rate samples of the output of a multipath medium. Our approach results in a sampling theorem for analog signals defined over an infinite union of subspaces. The proposed method leads to perfect recovery of the multipath delays from samples of the channel output at the lowest possible rate, which depends only on the number of multipath components and the transmission rate, and not on the bandwidth of the probing signal. By properly manipulating the low-rate samples, we show that the time delays can be recovered using the well-known ESPRIT algorithm. Combining results from sampling theory with those obtained in the context of direction of arrival estimation methods, we develop necessary and sufficient conditions on the transmitted pulse and the sampling functions in order to ensure perfect recovery of the channel parameters at the minimal possible rate.
As a kind of hypercomplex number with strict orthogonality, quaternion can bring many benefits when applied to the signalprocessing for electromagnetic vector sensorarray, but the quaternion model can deal two-compo...
详细信息
ISBN:
(数字)9781728190457
ISBN:
(纸本)9781728190464
As a kind of hypercomplex number with strict orthogonality, quaternion can bring many benefits when applied to the signalprocessing for electromagnetic vector sensorarray, but the quaternion model can deal two-component electromagnetic vector-sensors only. On the basis of quaternion model, this paper introduces biquaternion to establish a three-components electric dipole sensorarray model in time domain. The orthogonal information between electric dipoles is retained effectively, and the orthogonality between quaternions is more constrained than that between vectors, which can achieve better angle measurement performance. The direction of arrival (DOA) can be estimated by biquaternion MUSIC(BQ-MUSIC). At the same time, the complexity of the algorithm and the robust performance of related noise are analyzed and compared. The experimental results verify the effectiveness of the algorithm.
The performance of many analogue and digital signalprocessing systems is limited by nonlinear distortion mechanisms which can be modelled with a Volterra series. The nonlinear distortion can be compensated by the app...
详细信息
The performance of many analogue and digital signalprocessing systems is limited by nonlinear distortion mechanisms which can be modelled with a Volterra series. The nonlinear distortion can be compensated by the application of post (or pre)-distortion based on a Volterra inverse. The computational complexity associated with this type of compensation can be very high, particularly for systems with high nonlinearity order and long memory. We determine the 3rd and 5th order analytical Volterra inverses, and examine their associated computational complexity. We show how the analytical Volterra inverse can be used to determine the memory span of the kernels of an adaptive Volterra inverse, leading to computational complexity expressions. We then compare the computational complexity of the analytical and adaptive Volterra inverse. The results show that the analytical inverse has a much lower complexity than the adaptive inverse.
Recent advances in bio-sensing technologies have led to design of bio-sensorarrays for rapid identification and quantification of various biological agents such as drugs, gene expressions, proteins, cholesterol, fats...
详细信息
Recent advances in bio-sensing technologies have led to design of bio-sensorarrays for rapid identification and quantification of various biological agents such as drugs, gene expressions, proteins, cholesterol, fats, etc. Various dedicated sensing arrays are already available commercially to monitor some of these compounds in a sample. However, monitoring the simultaneous presence of multiple agents in a sample is still a challenging task. Multiple agents may often attach to the same probes on an array which makes it difficult to design a chip that can distinguish such agents (leading to low specificity). Thus, sophisticated algorithms for targets identification need to be implemented in biochip in order to maximize the number of distinguishable targets in the samples. The proposed algorithms are also required to introduce sophisticated signalprocessing and more intelligence on-chip. Dealing with these new processing and information technology demands constraints also require more innovative approaches towards hybrid integration technologies. To address such new demands, we discuss in this paper an innovative 3D-integrated bio-chips especially dedicated to label-free DNA detection.
Protocols for beamforming antennas usually direct the beam toward the respective communication partner. This requires significant coordination between nodes and results in frequent changes of the beam direction. In th...
详细信息
Protocols for beamforming antennas usually direct the beam toward the respective communication partner. This requires significant coordination between nodes and results in frequent changes of the beam direction. In this paper, we present much simpler algorithms that instead aim at improving connectivity and robustness of routing. A node computes the optimal beam direction using aggregate information about its neighborhood such as the number of neighbors in each beam direction. We analyze the performance of such algorithms in terms of number of paths to a destination, mutual interference, and route lifetime in mobile networks, and show that they are a promising alternative to existing beamforming schemes
Beam forming is being used in sensor networks to enhance it communication range. Dual beam can be formed from two sets of sensors array wherein each set forming beam pattern in different direction. When same data need...
详细信息
ISBN:
(纸本)9781467345279
Beam forming is being used in sensor networks to enhance it communication range. Dual beam can be formed from two sets of sensors array wherein each set forming beam pattern in different direction. When same data need to be transmitted to two different directions, one set of sensors array can be used to form dual beam. The random distribution of sensors causes the beam pattern deviation. The random distribution has been modeled as uniform and Gaussian variables. A compensation technique to reduce the errors has been proposed in this paper. It has been modeled as joint optimization problem and solved by LS estimation method. This above technique has been applied to various geometry such as Uniform Linear array(ULA) Uniform Circular array (UCA), Uniform Elliptical array(UEA) and Uniform Planar Rectangular array(UPRA) with random perturbation and it is observed that dual beamforming from single set of array has efficient distribution of energy and also enhanced data transmission rate.
The real-time ultrasonic imaging system can be achieved using a digital beamforming (DBF) method. The critical part of the DBF is the real-time sampled-delay focusing (SDF) which requires a large number of memories (F...
详细信息
ISBN:
(纸本)076951944X
The real-time ultrasonic imaging system can be achieved using a digital beamforming (DBF) method. The critical part of the DBF is the real-time sampled-delay focusing (SDF) which requires a large number of memories (FIFO) to store the scanned information. The sampled-delay focusing technique is used to eliminate the use of the analog delay lines. This paper concerns the design and implementation of pipelined sampled-delay architecture for ultrasonic digital beamforming. The design uses a minimum size look-up memory to store the initial scan information as opposed to previous approaches. The circuit is implemented in CMOS 0.18 /spl mu/m technology and the resulting active layout area is 0.14 mm/sup 2/, while its total power consumption is below 40 mW.
The development of microelectronic lab-on-a-chip devices (LOACs) can now be pursued thanks to advances in silicon technology. As these kinds of devices may integrate different functional units, much care has to be put...
详细信息
ISBN:
(纸本)076951944X
The development of microelectronic lab-on-a-chip devices (LOACs) can now be pursued thanks to advances in silicon technology. As these kinds of devices may integrate different functional units, much care has to be put in the design of control units which have to provide real-time control capabilities in order to deal with complex systems composed of sensors, actuators, signal conditioning and processing circuits. Moreover, reconfigurability and expandability are key design features to get a flexible and reusable architecture. The FPGA implementation of a control system for an existing LOAC is presented as a case study with emphasis on the advantages of a programmable device approach. The presented system has been implemented on an Altera EPF10K200S device and the achieved operating frequency is 20MHz. The device was successfully tested and experimental results are hereby shown.
暂无评论