An optical method for information storage in planar or volume media is proposed. Information decoding is done by tomographic methods. The principle of the method is described. A preliminary calculation for present 1-...
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ISBN:
(纸本)155752033X
An optical method for information storage in planar or volume media is proposed. Information decoding is done by tomographic methods. The principle of the method is described. A preliminary calculation for present 1-μm technology gives a dimension of 10 × 10 b in a memory as a convenient number, giving high information capacity (approximately 10,000 b/mm2) and short time for reconstruction.
An Electronic Library System (ELS) is currently being developed for use in commercial aircraft. This system will supplement and eventually replace the conventional paper manuals with electronically stored data. Using ...
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Matrix multiplication is well suited to optical techniques, since the size of the matrix has no direct influence on the speed with which the multiplication takes place. Although iterative techniques have been develope...
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ISBN:
(纸本)0879427094
Matrix multiplication is well suited to optical techniques, since the size of the matrix has no direct influence on the speed with which the multiplication takes place. Although iterative techniques have been developed to solve systems of linear equations, to find the eigenvectors of matrices, and to perform other matrix manipulations, research has been hampered somewhat by a lack of fast two-dimensional spatial light modulators (SLMs). advances in SLM technology are discussed, and different architectures for matrix processing are reported. Acoustic Bragg cells, liquid crystal devices, magnetooptic devices and silicon/PLZT crystal light modulators are briefly reviewed. Both systolic and fully parallel optical vector-matrix multipler configurations are described. Iterative optical processors and bimodal (analog-digital) optical computer accuracy are briefly considered.
An experimental 11-ns 8K × 18 SRAM (static random-access memory) which incorporates advances in processing technology and circuit design is discussed. Problems of making wide-data-path CMOS chips with tolerable n...
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An experimental 11-ns 8K × 18 SRAM (static random-access memory) which incorporates advances in processing technology and circuit design is discussed. Problems of making wide-data-path CMOS chips with tolerable noise and difficulties of interfacing next-generation technology chips with current technology have been resolved. The interface voltage levels are full TTL (transistor-transistor logic) swings. The chip has a 3.6-V power supply and uses 0.5 μm channel lengths. Numerous parts with all 144Kb operational have been seen. An on-chip test circuit has been implemented to aid in testing performance accuracy. The experimental fabrication technology is a 1.2-μm n-well CMOS process with 14-nm gate oxides.
The author discusses advances being made in information technology that could drastically change the profession of technical communication and the role of the technical communicator in developing and managing informat...
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The author discusses advances being made in information technology that could drastically change the profession of technical communication and the role of the technical communicator in developing and managing information. The advances discussed are in the fields of desktop computing, telecommunications and networks, opticalstorage, and artificial intelligence. The issues that these technological advances raise for educational programs in preparing technical communicators for the future are also discussed.< >
Experimental results are reported for an optical associative memory previously described. This system is a single-layer neural network architecture simulating a 2-D array of approximately 105 neurons on which images c...
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Experimental results are reported for an optical associative memory previously described. This system is a single-layer neural network architecture simulating a 2-D array of approximately 105 neurons on which images can be represented. This array is fully interconnected by holograms, and the system is organized as an autoassociative memory with feedback. An external image projected into the system causes one of the stored images to become a stable state of the system. The ability of the system to recognize distorted versions (e.g. rotated, shifted, or scaled) of a stored image depends critically on the gain of the system as the light goes around the loop. High gain provides invariance to distortions but ultimately it also leads to a loss in discrimination against unfamiliar images. Thus there is an optimum choice of parameters of the system that yields optimum performance. A description is given of how the parameters affect the performance of the memory, and the performance (in terms of discrimination vs. invariance) obtained by the experimental system is reported.
The hardware and software design and implementation of the data acquisition and processing systems of a laser wavemeter being built at NASA Langley Research Center are described. The wavemeter acquires sets of CCD/pho...
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The hardware and software design and implementation of the data acquisition and processing systems of a laser wavemeter being built at NASA Langley Research Center are described. The wavemeter acquires sets of CCD/photodiode array-image data, produced by three Fabry-Perot interferometers for a pair of laser pulses every 200 milliseconds. Each image contains 1766 pixels digitized to 12-bit resolution. The acquisition system is composed of three discrete A/D channels running at a 1-MHz conversion rate, three diode-array sensors and two 4K x 9 FIFOs. By taking advantage of the analog shift-register storage capability of the array, two sets of data can be read in rapid succession (less than 400 microseconds is required between laser firings, but data can be acquired faster) from each array. All six images are sent in interleaved fashion to the flight recorder for postprocessing on the ground, and one selected pair of these images is processed in semi-real-time by an 80286-based single-board computer to calculate the wavelength of a pulsed multimode Alexandrite laser.
The history of space laser communication is sketched. Three steps to establishing a link between platforms-acquisition, tracking, and communication-are described. It is suggested that future advances will greatly ease...
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The history of space laser communication is sketched. Three steps to establishing a link between platforms-acquisition, tracking, and communication-are described. It is suggested that future advances will greatly ease the tight tolerance requirements and bring down laser communication terminal costs as well as allow small aperture characteristics of space-based systems. This forecast based on rapid advances in semiconductor laser technology, especially at the GaAs laser wavelength. Also important will be the use of wide beams and smaller optics, coherent laser arrays, systems-on-a-chip, and MOCVD growth technology. technologyadvances will make systems smaller, lighter, and far less expensive.< >
A rewritable optical disk drive is described. The drive has a large storage capacity of 8.9 Gb/spindle with a few seconds of access time. It can store data economically in a small floor space, and it can be used as a ...
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A rewritable optical disk drive is described. The drive has a large storage capacity of 8.9 Gb/spindle with a few seconds of access time. It can store data economically in a small floor space, and it can be used as a supplement or partial alternative to magnetic disk drives or tape library units. The authors discuss the drive technologies, support software, and application of this subsystem.< >
The hardware and software design and implementation of the data acquisition and processing systems of a laser wavemeter being built at NASA Langley Research Center are described. The wavemeter acquires sets of CCD/pho...
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The hardware and software design and implementation of the data acquisition and processing systems of a laser wavemeter being built at NASA Langley Research Center are described. The wavemeter acquires sets of CCD/photodiode array-image data, produced by three Fabry-Periot interferometers for a pair of laser pulses every 200 milliseconds. Each image contains 1766 pixels digitized to 12-bit resolution. The acquisition system is composed of three discrete A/D channels running at a 1-MHz conversion rate, three diode-array sensors and two 4 K*9 FIFOs. By taking advantage of the analog shift-register storage, capability of the array, two sets of data can be read in rapid succession (less than 400 microseconds is required between laser firings, but data can be acquired faster) from each array. All six images are sent in interleaved fashion to the flight recorder for postprocessing on the ground, and one selected pair of these images is processed in semi-real-time by an 80286-based single-board computer to calculate the wavelength of a pulsed multimode Alexandrite laser.< >
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