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Deconvolution algorithms are given for the computer-aided design of transversal-filter equalizers. These filters can be used to filter signals from individual elements of a sensing array or for array equalization. Minimax design procedures are developed for both continuous-time and discrete-time cases. Also, least-square error and envelope-constrained designs are considered. Essential design equations, numerous computed examples, mathematical details, and several computer codes are included. (Author)

The key to meeting the extremely high throughput requirements of future military signal and image processing systems is parallelism in algorithms and hardware. This paper will describe the implementation of a core set of algorithms on one possible hardware implementation, designed to achieve high speed and efficient parallelism. This approach and design procedure, while using currently available integrated circuit building blocks, is similar to how this type of processor will be developed in the future using VLSI. Keywords: Systolic array, RAM, Algorithms, and Boundary processors.

This report covers the development, test and evaluation of an adaptive phased array optical processor. This system is designed to optimally process the wide band signals from large phased array antennas in real time, achieving a computational throughput approaching 10^15 multiplies per second, demonstrating the potential of optical-based architectures to surpass performance achievable with conventional technology. The processor uses a three-dimensional volume hologram to create and store adaptive weights to simultaneously perform beam steering and jammer-nulling functions. The adaptive processor consists of two sub-sections, the main beam steering processor and the jammer-nulling processor. The nature of the architecture is that the number of processor components used is independent of the number of elements in the phased array. The report contains extensive treatment of models and analytical expressions developed to relate system parameters and to predict expected system behavior and performance of the experimental signal processors. A variety of jammer scenarios are described and analyzed. Experimental results obtained in a working hardware configuration of the processor are shown to verify the theoretical models. The models guided the development and evolution of the experimental optical hardware system with increasingly improved performance. By improving component stability, electronic gain, and feedback loop isolation, 45 dB jammer cancellation was demonstrated in the experimental system. Also described are results of main beam formation experiments that did not require a priori knowledge of the angle-of-arrival of the desired signal. In addition, results from simultaneous operation of both the nulling processor and the main beam processor are presented. The report contains extensive references and bibliography of the twenty technical papers published in con

Radar systems often use low power, continuous waveform radio frequency (RF) modulations and require high-speed adaptive signal processors to provide the necessary processing gain to detect small radar cross-section targets in clutter on range-Doppler maps. Counter-radar technologies include digital RF memories (DRFMs) that attempt to provide multiple, structured false targets with clutter, for example, using a pipelined, finite impulse response arrangement of complex range bin processors. This thesis investigates high-capacity field-programmable gate array (FPGA) technology to enable on-the-fly flexibility and reconfigurability for both radar signal processing and DRFM electronic attack using a Xilinx Virtex Ultrascale+. A three-stage range, Doppler, post-detection integration radar modulation compression circuit is designed and quantified. A range compression circuit with a peak power consumption of 6.100W and a post-implementation utilization of 11% was designed. The Doppler filter bank was designed at 400 MHz with a peak power consumption of 2.688W and a post-implementation utilization of 9%. A coherent integration processor at 400 MHz had a peak power consumption of 2.517W and a post-implementation utilization of 9%. In addition, a DRFM complex range bin processor was designed and quantified at 500 MHz and had a peak power 2.543W with a post-implementation utilization of 11%.

Radar systems often use low power, continuous waveform radio frequency (RF) modulations and require high-speed adaptive signal processors to provide the necessary processing gain to detect small radar cross-section targets in clutter on range-Doppler maps. Counter-radar technologies include digital RF memories (DRFMs) that attempt to provide multiple, structured false targets with clutter, for example, using a pipelined, finite impulse response arrangement of complex range bin processors. This thesis investigates high-capacity field-programmable gate array (FPGA) technology to enable on-the-fly flexibility and reconfigurability for both radar signal processing and DRFM electronic attack using a Xilinx Virtex Ultrascale+. A three-stage range, Doppler, post-detection integration radar modulation compression circuit is designed and quantified. A range compression circuit with a peak power consumption of 6.100W and a post-implementation utilization of 11% was designed. The Doppler filter bank was designed at 400 MHz with a peak power consumption of 2.688W and a post-implementation utilization of 9%. A coherent integration processor at 400 MHz had a peak power consumption of 2.517W and a post-implementation utilization of 9%. In addition, a DRFM complex range bin processor was designed and quantified at 500 MHz and had a peak power 2.543W with a post-implementation utilization of 11%.

Contains the text of 139 contributed papers and 4 invited plenary talks, documenting recent advances in the theory and applications of statistical signal and array processing. The center of focus is 'SSAP for communications', with other sessions devoted to detection, estimation and spectral analysis, array processing, non- Gaussian signals, multichannel models, source separation, nonlinear models, and non-stationary signals.

The research activities have focussed on the VLSI array processor for signal processing theory and algorithms and the development of parallel computing architectures. A solution in today's VLSI research challenge lies in a cross-disciplinary research encompassing the areas of mathematics, algorithms, computers, and applications. To this end, this report summarizes two parallel major research tasks: (1) Signal processing algorithm and theory and (2) Parallel computing structures.

The research activities have focussed on the VLSI array processor for signal processing theory and algorithms and the development of parallel computing architectures. A solution in today's VLSI research challenge lies in a cross-disciplinary research encompassing the areas of mathematics, algorithms, computers, and applications. To this end, this report summarizes two parallel major research tasks: (1) Signal processing algorithm and theory and (2) Parallel computing structures.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

This report describes the implementation of a MIMD array computer designed and built at the Lincoln Laboratory for signal processing. Some of the software tools needed to successfully use such an array are discussed, and the software package written to allow debugging of the array from a host computer is described. The first application or the array, a 12-channel filter bank front- end for a speech recognition system, is discussed. Finally, a block diagram compiler is described. This compiler converts block diagrams, entered at a CAE workstation, into efficient assembly code for all cells in the array. Keywords include: Block diagram compiler; Digital signal processing; MIMD architecture; Multiprocessor; and Processor arrays.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

The investigation of array antenna electrooptical signal processors continues with emphasis placed on the development of a wide-band solid light modulator. The light modulator bandwidth and the transfer characteristics between input voltage and peak phase deviation of light wave front are obtained experimentally for fused silica light modulators operating in the compression mode. Transfer characteristics are found to be linear as predicted by theory, and bandwidth is found to be greater than 50 per cent of resonant transducer frequency. Electromechanical cross coupling and ultrasonic beam broadening are investigated for both the shear and compression modes by means of Schlieren techniques. Results show that in a multi-channel configuration, adjacent light modulator channels may be spaced by one transducer width without adverse effects. First order diffraction patterns are obtained for the fused silica light modulator. Results are consistent with theory showing that no optical distortion is introduced by ultrasonic propagation in fused silica.

The objective of this specific project was to design and construct a new generation flying wing underwater glider, dubbed ZRay, based upon the experience developed over the past three years (2006-2008) of at-sea testing with XRay (under ONR grant N00014-04-1-0558). The new design developed during this project includes several innovations that significantly improve a Liberdade glider's persistence, passive sensing capability, and robustness

The objective of this specific project was to design and construct a new generation flying wing underwater glider, dubbed ZRay, based upon the experience developed over the past three years (2006-2008) of at-sea testing with XRay (under ONR grant N00014-04-1-0558). The new design developed during this project includes several innovations that significantly improve a Liberdade glider's persistence, passive sensing capability, and robustness

Array signal processing is a well-established area of research, spanning from phased array antennas in the middle of the last century to hands-free audio in recent years. As devices incorporating microphone arrays begin to appear in the home, new practical challenges are presented to well-known signal processing problems such as source localization and beamforming. In this talk, we consider some new algorithms that use multichannel observations outside the common beamforming paradigm. These include dereverberation using spatiotemporal averaging, acoustic channel shortening and the acoustic Rake receiver, with relevant audio examples. We also investigate the problem of localizing reflecting boundaries in an acoustic space by considering the time of arrival of 1st-order reflections. Such algorithms are expected not to replace but to compliment beamforming in new and robust future applications. ©2011 Microsoft Corporation. All rights reserved.

The major emphases of the research proposal submitted to the Office of Naval Research in 1986 were in the development of new technique for coherent signal identification using multiple sensor elements and performance analysis of eigenstructure-based high resolution methods for direction finding. This research report concerns primarily with new development (since the last report data) in the detection of signals from measurements made at the output of a set of spatially deployed sensor element. Three key results that have obtained during this investigation is reported in section 2 with all details. To be specific, they are: In the context of coherent signal classification, a spatial smoothing scheme first suggested Evans et al., and subsequently studied by Shan et al., is further investigated. It is proved in section 2.1 that by making use of a set of forward and complex conjugated backward subarrays simultaneously, it is always possible to estimate any K directions of arrival using at most 3K/2 sensor elements. Section 2.2 presents a detailed asymptotic analysis of a class of high resolution estimators for resolving correlated and coherent plane waves in noise. These estimators are in turn constructed from certain eigenvectors associated with spatially smoothed(or unsmoothed) covariance matrices generated from a uniform array. Finally, a technique for estimating the directions of arrival of multiple signals utilizing the generalized eigenvalues associated with certain matrices generated from the signal subspace eigenvectors is proposed in section 2.3. (RH)

The multiple measurement vector (MMV) problem addresses the identification of unknown input vectors that share common sparse support. Even though MMV problems had been traditionally addressed within the context of sensor array signal processing, the recent trend is to apply compressive sensing (CS) due to its capability to estimate sparse support even with an insufficient number of snapshots, in which case classical array signal processing fails. However, CS guarantees the accurate recovery in a probabilistic manner, which often shows inferior performance in the regime where the traditional array signal processing approaches succeed. The apparent dichotomy between the {\em probabilistic} CS and {\em deterministic} sensor array signal processing have not been fully understood. The main contribution of the present article is a unified approach that unveils a {missing link} between CS and array signal processing. The new algorithm, which we call {\em compressive MUSIC}, identifies the parts of support using CS, after which the remaining supports are estimated using a novel generalized MUSIC criterion. Using a large system MMV model, we show that our compressive MUSIC requires a smaller number of sensor elements for accurate support recovery than the existing CS methods and can approach the optimal $l_0$-bound with finite number of snapshots.

The use of high resolution methods of processing acoustic array data for source localization in shallow-water waveguide environments has been the focus of much research in recent years. It has been noted that, whereas these methods rely on sophisticated models of the acoustic environment, they are subject to degraded performance in the presence of mismatch, such as might occur when environmental parameters are incorrectly estimated. Estimators that have been analyzed in this way include Capon's 'maximum likelihood method' (MLM), also called the 'minimum variance distortionless response,' and the "sector-focusing' method (SFM) of Byrne. (AN)

A series of 16-inch square by 2-inch thick, multi-layered ceramic composite armor specimens have been inspected using a 128 element, 10MHz immersion phased array ultrasound system. Some of these specimens had intentional design defects inserted interior to the specimens. Because of the very large changes in acoustic velocities of the various layered materials, ultrasonic wave propagation is problematic. Further, since the materials used in the layers were stacked such that a lower elastic modulus material was on one side and a higher elastic modulus material was on the other, the side selected for ultrasonic insonification became a significant parameter. To overcome some aspects of the issues with the acoustic wave propagation, two digital signal processing methods were employed. These were: 1)- use of fast Fourier transforms (FFT) and 2)-an integrated signal analysis. Each method has strengths and weaknesses with application in part dependent upon the side of sample used for insonification. The results clearly show that use of these methods significantly improves defect detection. This paper presents the details of the samples used, the issues with ultrasonic wave propagation, a discussion of the two digital signal processing algorithms and results obtained.

The results of a series of off-line signal processing experiments are presented for the experimental Large Aperture Seismic Array (LASA) located in eastern Montana. In particular, the signal-to-noise ratio gains achievable by maximum-likelihood processing, as well as other simpler forms of processing, are given as a function of frequency, aperture, and number of sensors. A partial discussion of the physical characteristics of the noise field which led to these results is also presented. The spurious precursor introduced by one for of signal processing, and shown to be caused primarily by the signal amplitude scatter within a subarray, can be effectively reduced by using amplitude equalization. The signal amplitude scatter within a subarray, and between subarrays, is thus found not to degrade seriously the performance of the signal processing. In fact, the scatter of amplitudes between subarrays, which is significantly larger than that within a subarray, is a definite asset. It was found that the effectiveness of the processing depends not only on the array spatial filtering ability, but on differences in absolute level of the noises in the various sensors. Long-period array data from the extended TFO array were processed and showed roughly square root of N improvement. Our experience in processing a number of events is illustrated by a discussion of the results obtained on two particularly weak events with the maximum-likelihood filter. The apparent magnitude of one event (as averaged over the LASA) was 3.5, and that of the other was 4.0.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

In recent years there have been increasing interest in eigenstructure based array signal processing techniques especially in the areas of radar and sonar processing and in signal separation applications as found in communications or speech acquisition/enhancement. However, model errors are not accounted for in these methods. Unfortunately, the problem of model error is a ubiquitous part of real systems: they arise from such phenomena as non-ideal sensor characteristics (eg., sensor calibration errors in phase and gain, etc.), unknown source characteristics and locations, etc. This report is broadly divided into two parts. The first part examines the effects of model errors on the performance of existing eigenstructure based methods in array signal processing. A statistical analysis of the ESPRIT (Estimation of Signal Param via Invariance Techniques) algorithm under random model errors is performed. The analysis provides interesting insight into the sensitivity of ESPRIT to model errors: in particular, for uniform linear arrays of sensors, it is found that the mean square error of DOA (direction of arrival) estimates found using ESPRIT is almost totally dependent on errors in sensor phases and not that of sensor gains.

We developed statistical time-reversal imaging and Cramer-Rao bounds (ORB's) for point targets and scatterers; realistic clutter modeling, random scattering reflections, compound Gaussian distributions, and signal dependence; maximum likelihood estimators, CRB's, and sequential target detectors in compoun%Gaussian clutter; polarimetric radar algorithms for detectingltracking targets in clutter; microstrip antennas design with suppressed radiation in horizontal directions and reduced coupling, and 6D vector antenna; optimal synthesis of a directional beam with full polarization control; estimated building layouts and objects behind walls using exterior radar measurements and EM modeling; robust least-squares beamformers (spatial filters) for estimating unknown source signals under steering vector uncertainties; tight lower bounds on the mean-square error (MSE) of estimating multiple change points of measurement models; unification of minimal Bayesian bounds on the MSE of estimators; performance bounds on image registration useful for optimum design of registration algorithms; image reconstruction method for diffuse optical tomography; electromagnetic inverse solutions based on Poisson oint 5 atial model for estimatin unknown source e. ., brain Si nals.

This paper aims to describe a hybrid technique that combines the feasibility of our recently developed Multiresolution Analysis of Signal Subspace Invariance Technique (MASSIT) with the Finite Element Method (FEM) analytic model developed to obtain accurate localization scheme of neural sources in an extracellular recording environment. The power of the proposed method stems from the fact that robust array signal processing approach is fused with the FEM analysis yielding the closest scenario to practical experimental situations. Results from experimental signal and noise simulated composite are summarized and the overall performance is evaluated.

Quaternion-valued wireless communication systems have been studied in the past. Although progress has been made in this promising area, a crucial missing link is lack of effective and efficient quaternion-valued signal processing algorithms for channel equalisation and beamforming. With most recent developments in quaternion-valued signal processing, in this work, we fill the gap to solve the problem and further derive the quaternion-valued Wiener solution for block-based calculation.

A short trial has been conducted in shallow water using a towed array and a number of signal-processing techniques. Results are presented on the outputs from conventional beamforming and maximum-likelihood beamforming and on some basic techniques for suppressing towship noise. The signal processing package is implemented in software and provides the various forms of processing by using the array covariance matrix and eigenvalue/vector analysis. Possible future work on these topics is proposed.

Performance of a vertical array for estimating multipath signal parameters and for detecting multipath Gaussian signals is investigated. For known multipath signal direction cases, the parameters of the signal from each individual path may be estimated so that the multipath signal cancellation can be eliminated. The performance of the Maximum Likelihood Estimates (MLE) for the signal parameters of individual paths are shown to be dependent on the angular separation of signal paths and array length. The maximum A Posteriori Probability Estimate (MAP) is considered when the signal statistics are known. The linear relationship between the MLE and MAP estimates is also shown. The Bayesian optimum array processor for detecting multipath Gaussian signals with known arrival angles not only has multiple beamformers pointing on multipath signal directions, but also has an additional structure which cross-correlates multiple beams. Optimum detection performance of a vertical array can be evaluated by an analytical method if the array has no more than four elements. With the aid of a digital computer the optimum performance can be calculated for an array of any size. The trade-off between the processor structure complexity and the detection performance is shown in terms of receiver operating characteristic (ROC) curves and processor block diagrams. A two-path example is shown for the performance comparison between optimum detector, single beamformer and double beamformer arrays. (Author)

The processing of short-period P-wave data from a continental aperture seismic array is considered. The array consists of sites located at the Large Aperture Seismic Array (LASA) in eastern Montana and Long Range seismic Measurement (LRSM) stations located in North America. In particular, the feasibility of recognizing the arrival of the pP phase, making use of P-pP differences in velocity across such a large array, is considered. In addition, the determination of the P-wave source structure of an event is considered by using the array to essentially steer many beams in the vicinity of the epicenter of the event. The capability of the array to perform these two functions is evaluated and discussed in detail.

Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

A signal processing procedure is designed for a hypothetical low frequency sonar array. The design process is based upon the normal mode expansion of the signal field. Unusual problems associated with this expansion are discussed and some useful simplifications are found. Basic array processing formulations are redeveloped to accommodate the possibility of a signal field which is a superposition of known wave fronts.

A signal processing procedure is designed for a hypothetical low frequency sonar array. The design process is based upon the normal mode expansion of the signal field. Unusual problems associated with this expansion are discussed and some useful simplifications are found. Basic array processing formulations are redeveloped to accommodate the possibility of a signal field which is a superposition of known wave fronts.

The results of a series of off-line signal processing experiments are presented for long-period data obtained from the Large Aperture Seismic Array (LASA) located in eastern Montana. The signal-to-noise ratio gains obtained with maximum-likelihood processing, as well as other simpler forms of processing, are presented for body-wave as well as surface-wave phases. A discussion of the frequency-wavenumber characteristics of the noise which led to these results is also given. On the basis of these experiments several recommendations are made concerning optimum long-period array configurations and on-line or off-line processing methods. The usefulness of maximum-likelihood processing in suppressing an interfering teleseism is demonstrated. An experiment is given in which maximum-likelihood processing achieved about 20-db suppression of an interfering teleseism, while simpler forms of processing such as beamforming obtained about 11 db. The matched filtering of surface waves using chirp waveforms is also discussed. The most useful discriminant for distinguishing between natural seismic events and underground nuclear explosions, using both the long-period and short-period data, was found to be that based on the relationship between the surface-wave and body-wave magnitudes. Measurements of this discriminant made on events from four tectonic regions of the earth are presented. It is shown that 60, 100 percent detectability of surface waves for natural seismic events from the Central Asian-Kurile Islands-Kamchatka region occurs at about LASA body-wave magnitudes 4.5, 4.9, respectively.

The work reported on here has been exclusively concerned with the digital domain operation of charge coupled devices. One common example of the digital use of charge coupled devices is in the area of memory. But in the present context, we mean a great deal more than just memory. Generally speaking, any digital domain function can be accomplished with charge coupled devices; this means, in particular, digital charge coupled logic (DCCL) functions and digital arithmetic functions. Putting aside for the moment the question of how this is done, let us first ask why this would be done. After all, the charge coupled device technology produces a unique device in that it works as a sampled data analog system. In view of the fact that the CCD is unique in this respect, what are the advantages of using the device in the digital domain. This can be answered by addressing an even more fundamental question; namely, why use any digital device. The reason that people have been using digital devices for some time can be summarized in a few statements: (1) Freedom from parameter variations; (2) Freedom from environment and environment changes; (3) Flexible in application; (4) Easily programmable; (5) Arbitrary accuracy in calculations; (6) Well known characteristics that are easily modeled and simulated; and (7) Low cost due to widespread use.

xix, 796 p. : 27 cm

From the bitsavers.org collection, a scanned-in computer-related document. components :: amd :: bitslice :: 1986 Array Processing and Digital Signal Processing Handbook

The work established the viability of a fiber-optic approach for low-loss true time delay of wideband RF signals for phased-array antenna (PAA) beamsteering. In this approach an optical carrier modulated by the RF signal of interest is launched into a delay-line fiber composed of optical Bragg reflection gratings written holographically into the core of a single-mode fiber. The beam is steered by tuning the optical carrier wavelength for reflection from the appropriate grating. The fiber Bragg grating writing performance meets and exceeds PAA requirements. We demonstrated: (1) a time delay accuracy of approximately 2 ps (20 Ps verified); (2) a wavelength writing accuracy for Bragg gratings of 0.04 microns absolute, 0.01 nm relative; (3) a sidelobe suppression of 50 dBe at 2 nm channels and 60 dBe at 3 nm channels. We produced a 4-bit, 16 grating true time delay element which includes an optical circulator. An analytical model, which includes chirp, was developed that predicts both the optical and RF response for the fiber optic Bragg grating.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

Research was ongoing in several areas: stable array processing; two-dimensional reconstruction algorithms; extensions of the concept of cross-entropy distance measures; and the beginning of new work on array processing in more complicated acoustic environments.

In this paper, the Weiss-Weinstein bound is analyzed in the context of sources localization with a planar array of sensors. Both conditional and unconditional source signal models are studied. First, some results are given in the multiple sources context without specifying the structure of the steering matrix and of the noise covariance matrix. Moreover, the case of an uniform or Gaussian prior are analyzed. Second, these results are applied to the particular case of a single source for two kinds of array geometries: a non-uniform linear array (elevation only) and an arbitrary planar (azimuth and elevation) array.

In applying the Wiener multichannel time-series processing theory to seismic arrays for teleseismic signal extraction, the transient nature of the signal is not used. This report presents the theoretical development of optimum nontime-stationary signal-extraction filters which take advantage of the additional information of known signal-arrival time. The matrix inversion is made computationally practical by using an extension of the Levinson technique to determine prediction filters several points into the future. A sequence of programs to accomplish the filter design and application is described and illustrated by a sample problem. Significant improvement in mean-square error was not obtained for this sample problem compared to classical Wiener filters. Full evaluation of this technique requires additional data processing and examination with respect to criteria other than mean-square error.

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For the purpose of localizing a distant noisy target, or inversely, calibrating the receiving array, the time delays defined by the propagation across the array of the target-generated signal wavefronts are to be estimated in the presence of array self-noise. The Cramer-Rao matrix bound is used to show that either properly filtered beamformers or properly filtered systems of multiplier correlators can be used to provide efficient estimates. The effect of suboptimally filtering the array outputs is discussed.

The utility of organic salts related to 4-Dimethylamino-N-methyl Stilbazolium Tosylate, DAST, to display very useful optoelectronic properties has been broadly investigated and continues to yield new information. New materials have been developed having improved optical and physical properties. Methods for crystal growth and handling have been developed which allow the design and fabrication of useful optoelectronic devices. Design and fabrication of a linear array of high performance Fabry-Perot etalons is described. DAST, Fabry-Perot etalon, Optical modulator, Organic NLO materials.

This is the Proceedings of the 10th IEEE Workshop on Statistical Signal and Array Processing (SSAP), which was held at the Pocono Manor Inn, Pocono Manor, Pa during the period of August 14th-16th, 2000. The Workshop featured four keynote speakers whose talks covered the areas of Radar and Sonar Signal Processing; Time-Delay Estimation; Space-Time Codes; and Multi-carrier CDMA. The Workshop offered traditional and new research topics. it included one session on Radar Signal Processing, one session on Signal Processing for GPS, one session on Network Traffic Modeling, one session on Statistical Signal Processing, one session on Acoustical Signal Processing, two sessions on Time-Frequency Analysis, two sessions on Array Processing, three sessions on Second and Higher Order Statistics, and four sessions on Signal Processing for Communications. The workshop received the highest number of paper submissions compared to previous workshops in the same area, and the technical committee carefully selected high quality papers for presentations. The 2000 IEEE-SSAP Workshop was a tremendous success in all aspects.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

The purpose of this project is to apply physics-based signal and array processing techniques, recently developed in the area of underwater acoustics, to atmospheric infrasound data and co-located seismic field data. The source of the infrasound data is the newly installed International Monitoring System (IMS) infrasound station at Pinon Flat (PFO). The seismic data are being collected by the Southern California ANZA seismic network. Installation of the eight sensors that comprise the infrasound station at PFO was completed by mid April of this year. The space filters of the array (18 m for the inner centered triangle elements and 70 m for the outer centered triangle elements) also are nearly all in place. Preliminary data collected by this array contain some signals with significant spatial coherence across the array aperture. In particular, a large event with high signal-to-noise ratio was recorded on 23 April. Analyses of the arrival structure of this signal are presented in this paper. In addition, the spatial and temporal properties of the background noise in relation to the local environmental conditions are discussed. A focused experiment involving the temporary installation of additional infrasound sensors to provide larger array aperture is being planned for this summer. A description of the planned experiment is presented below.

Both planar thin film and channel optical waveguides have been integrated with charge-coupled devices (CCDs). Coupling of light from the waveguide region to the detector elements utilizes a smooth and uniformly-tapered region of SiO2 to minimize scattering. CCd transfer inefficiency of 1.0 times ten to the minus fourth power is consistently obtained for a number of devices. A channel waveguide array formed in a fan-out pattern is introduced as a means of enhancing focal plane resolution in integrated optical devices using optical waveguide lenses. High spatial resolution can thus be obtained without making detector spacings too small, thus avoiding detector problems with regard to fabrication, crosstalk, linearity, and charge transfer inefficiency. Operation of an integrated optical channel waveguide array-CCD transversal filter is reported. Channel waveguides formed in V-grooves couple directly to the sensor elements of the four phase, double polysilicon CCD. Experimental results include a filter transfer function having good agreement with theoretical results. The voltage contrast mode of a scanning electron microscope (SEM) is utilized to observe charge-coupled devices (CCDs) which have been cross sectioned. A new cross sectioning technique which uses anisotropic etching to accurately define the axis along which fracture occurs is presented.

This paper considers array processing for a sensor array when the signal is composed of a superposition of wave fronts. The array processing requires a multiple-signal parameter formulation. Existing array processing theory is generalized. The required signal processing functions should not be referred to as beam forming, because a matrix estimation operator is required. The rank of the estimation operator is greater than 1. Keywords: Signal processing, Ray processing, Beam forming.