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Stable density gradient forms in pond saturated with disodium phosphate (DSP). Volume of DSP saturated water tends to develop temperature and density layers. Since tests indicate thermal and density gradients remain in equilibrium at heat removal rates of 60 percent or more of heat input rate, pond containing DSP would be suitable for collecting solar energy and transferring it to heat exchanger for practical use.
The Decision Support Problem (DSP) technique for aircraft design is presently demonstrated through the development of a compromise DSP template for the conceptual design of subsonic transport aircraft. System variables are wing span and area, fuselage diameter and length, takeoff weight, and installed thrust. Such system constraints as range and wing loading are represented algebraically using standard subsonic aircraft theory, and economic efficiency is modeled in terms of rates-of-return. The DSP template thus obtained has been tested and validated using the known mission requirements and design constants of the B 727-200 airliner.
The Vibration Pattern Imager (VPI) system was designed to control and acquire data from scanning laser vibrometer sensors. The PC computer based system uses a digital signal processing (DSP) board and an analog I/O board to control the sensor and to process the data. The VPI system was originally developed for use with the Ometron VPI Sensor, but can be readily adapted to any commercially available sensor which provides an analog output signal and requires analog inputs for control of mirror positioning. The sensor itself is not part of the VPI system. A graphical interface program, which runs on a PC under the MS-DOS operating system, functions in an interactive mode and communicates with the DSP and I/O boards in a user-friendly fashion through the aid of pop-up menus. Two types of data may be acquired with the VPI system: single point or 'full field.' In the single point mode, time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and is stored by the PC. The position of the measuring point (adjusted by mirrors in the sensor) is controlled via a mouse input. The mouse input is translated to output voltages by the D/A converter on the I/O board to control the mirror servos. In the 'full field' mode, the measurement point is moved over a user-selectable rectangular area. The time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and converted to a root-mean-square (rms) value by the DSP board. The rms 'full field' velocity distribution is then uploaded for display and storage on the PC.
The University of Hawaii Institute for Astronomy CCD Camera Control System consists of a NeXT workstation, a graphical user interface, and a fiber optics communications interface which is connected to a San Diego State University CCD controller. The UH system employs the NeXT-resident Motorola DSP 56001 as a real time hardware controller. The DSP 56001 is interfaced to the Mach-based UNIX of the NeXT workstation by DMA and multithreading. Since the SDSU controller also uses the DPS 56001, the NeXT is used as a development platform for the embedded control software. The fiber optic interface links the two DSP 56001's through their Synchronous Serial Interfaces. The user interface is based on the NeXTStep windowing system. It is easy to use and features real-time display of image data and control over all camera functions. Both Loral and Tektronix 2048 x 2048 CCD's have been driven at full readout speeds, and the system is intended to be capable of simultaneous readout of four such CCD's. The total hardware package is compact enough to be quite portable and has been used on five different telescopes on Mauna Kea. The complete CCD control system can be assembled for a very low cost. The hardware and software of the control system has proven to be quite reliable, well adapted to the needs of astronomers, and extensible to increasingly complicated control requirements.
We discuss a Numerical Spectral Mode (NSM) that extends from the ground up into the thermosphere and incorporates Hines' Doppler spread parameterization (DSP) for small scale gravity waves (GW). This model is applied to describe the seasonal variations in the mean zonal circulation, the semi-annual and quasi-biennial oscillations (SAO and QBO), as well as the tides and planetary waves in the middle atmosphere. Initial results showed that this model can reproduce the salient features observed, including the QBO extending into the upper mesosphere inferred from UARS measurements. The model has now been extended to simulate also: (a) the zonal circulation of the lower stratosphere and upper troposphere, and (b) the upwelling at equatorial latitudes associated with the Brewer Dobsen circulation that affects the dynamics significantly as pointed out by Dunkerton. Upward vertical winds increase the period of the QBO observed from the ground. To compensate for that, one needs to increase in the model the eddy diffusivity and the GW momentum flux, bringing the latter closer to values recommended in the DSP. This development is conducive to extending the QBO and SAO to higher latitudes through global scale momentum redistribution. Multi-year interannual oscillations are generated through wave filtering by the solar driven annual oscillation in the zonal circulation. In a 3D version of the model, wave momentum is absorbed and dissipated by tides and planetary waves. A somewhat larger GW source (well within the DSP range) is then required to generate realistic QBO and SAO amplitudes. Since GW momentum is deposited in the altitude regime of increasing winds, the amplitude of the diurnal tide is amplified and its vertical wavelength is reduced at altitudes between 70 and 120 km. Wave filtering by the mean zonal circulation causes the GW flux to peak during equinox, and this produces a large semi-annual variation in the tide that has been observed on UARS. Without the diurnal tide, the semidiurnal tide would also be modulated in this way. But the diurnal tide filters out the GW preferentially during equinox, so that the semidiurnal tide tends to peak during solstice. Under the influence of GW, the tides are modulated significantly by planetary waves that are generated preferentially during solstice in part due to baroclinic instability.
There were two related parts to this work. The first, conducted at The Aerospace Corporation was to develop and define methods for integrating the statistical theory of brittle strength with conventional finite element stress analysis, and to carry out a limited laboratory test program to illustrate the methods. The second part, separately funded at Aerojet Electronic Systems Division, was to create the finite element postprocessing program for integrating the statistical strength analysis with the structural analysis. The second part was monitored by Capt. Jeff McCann of USAF/SMC, as Special Study No.11, which authorized Aerojet to support Aerospace on this work requested by NASA. This second part is documented in Appendix A. The activity at Aerojet was guided by the Aerospace methods developed in the first part of this work. This joint work of Aerospace and Aerojet stemmed from prior related work for the Defense Support Program (DSP) Program Office, to qualify the DSP sensor main mirror and corrector lens for flight as part of a shuttle payload. These large brittle components of the DSP sensor are provided by Aerojet. This document defines rational methods for addressing the structural integrity and safety of large, brittle, payload components, which have low and variable tensile strength and can suddenly break or shatter. The methods are applicable to the evaluation and validation of such components, which, because of size and configuration restrictions, cannot be validated by direct proof test.
Hines' Doppler spread parameterization (DSP) for small scale gravity waves (GW) is applied in a global scale numerical spectral model (NSM) to describe the semi-annual and quasi-biennial oscillations (SAO and QBO) as well as the long term interannual variations that are driven by wave mean flow interactions. This model has been successful in simulating the salient features observed near the equator at altitudes above 20 km, including the QBO extension into the upper mesosphere inferred from UARS measurements. The model has now been extended to describe also the mean zonal and meridional circulations of the upper troposphere and lower stratosphere that affect the equatorial QBO and its global scale extension. This is accomplished in part through tuning of the GW parameterization, and preliminary results lead to the following conclusions: (1) To reproduce the upwelling at equatorial latitudes associated with the Brewer/Dobson circulation that in part is modulated in the model by the vertical component of the Coriolis force, the eddy diffusivity in the lower stratosphere had to be enhanced and the related GW spectrum modified to bring it in closer agreement with the form recommended for the DSP. (2) To compensate for the required increase in the diffusivity, the observed QBO requires a larger GW source that is closer to the middle of the range recommended for the DSP. (3) Through global scale momentum redistribution, the above developments are conducive to extending the QBO and SAO oscillations to higher latitudes. Multi-year interannual oscillations are generated through wave filtering by the solar driven annual oscillation in the zonal circulation. (4) In a 3D version of the model, wave momentum is absorbed and dissipated by tides and planetary waves. Thus, a somewhat larger GW source is required to generate realistic amplitudes for the QBO and SAO.
A real-time display of tissue ischemia which comprises three CCD video cameras, each with a narrow bandwidth filter at the correct wavelength is discussed. The cameras simultaneously view an area of tissue suspected of having ischemic areas through beamsplitters. The output from each camera is adjusted to give the correct signal intensity for combining with, the others into an image for display. If necessary a digital signal processor (DSP) can implement algorithms for image enhancement prior to display. Current DSP engines are fast enough to give real-time display. Measurement at three, wavelengths, combined into a real-time Red-Green-Blue (RGB) video display with a digital signal processing (DSP) board to implement image algorithms, provides direct visualization of ischemic areas.
The Retinex is an image enhancement algorithm that improves the brightness, contrast and sharpness of an image. It performs a non-linear spatial/spectral transform that provides simultaneous dynamic range compression and color constancy. It has been used for a wide variety of applications ranging from aviation safety to general purpose photography. Many potential applications require the use of Retinex processing at video frame rates. This is difficult to achieve with general purpose processors because the algorithm contains a large number of complex computations and data transfers. In addition, many of these applications also constrain the potential architectures to embedded processors to save power, weight and cost. Thus we have focused on digital signal processors (DSPs) and field programmable gate arrays (FPGAs) as potential solutions for real-time Retinex processing. In previous efforts we attained a 21 (full) frame per second (fps) processing rate for the single-scale monochromatic Retinex with a TMS320C6711 DSP operating at 150 MHz. This was achieved after several significant code improvements and optimizations. Since then we have migrated our design to the slightly more powerful TMS320C6713 DSP and the fixed point TMS320DM642 DSP. In this paper we briefly discuss the Retinex algorithm, the performance of the algorithm executing on the TMS320C6713 and the TMS320DM642, and compare the results with the TMS320C6711.
The magnetically suspended reaction wheel assembly (MSRWA) is the product of a development effort funded by the Air Force Materials Laboratory (AFML) at Wright Patterson AFB. The specific objective of the project was to establish the manufacturing processes for samarium cobalt magnets and demonstrate their use in a space application. The development was successful on both counts. The application portion of the program, which involves the magnetically suspended reaction wheel assembly, is emphasized. The requirements for the reaction wheel were based on the bias wheel requirements of the DSP satellite. The tasks included the design, fabrication, and test of the unit to the DSP program qualification requirements.
The results of high-precision electron microprobe analyses on relic forsterites in 13 different deep sea particles (DSP) are described, comparing their 'minor' element (Mn, Cr, Ca, Ti, Al) signatures with those of olivines found in several types of meteorites. The results show that the DSP olivines do not match those from terrestrial and lunar rocks and achondritic meteoroties, match poorly those of the carbonaceous Allende (CV3) and Orgeuil (CI) meteorites, but are well matched with olivines from C2 meteorites, including the unusual Belgica 7904 meteorite.
A programmable image compression system which has the necessary flexibility to address diverse imaging needs is described. It can compress and expand single frame video images (monochrome or color) as well as documents and graphics (black and white or color) for archival or transmission applications. Through software control, the compression mode can be set for lossless or controlled quality coding; the image size and bit depth can be varied; and the image source and destination devices can be readily changed. Despite the large combination of image data types, image sources, and algorithms, the system provides a simple consistent interface to the programmer. This system (OPTIPAC) is based on the TITMS320C25 digital signal processing (DSP) chip and has been implemented as a co-processor board for an IBM PC-AT compatible computer. The underlying philosophy can readily be applied to different hardware platforms. By using multiple DSP chips or incorporating algorithm specific chips, the compression and expansion times can be significantly reduced to meet performance requirements.
Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed.
Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed.
In mobile radio systems, the relatively inefficient use of the spectrum by existing Frequency Modulation (FM) techniques is limiting the available channels. Linear modulation methods are thought to provide the necessary push into more efficient usage of the spectrum. The limitation, to date, of the linear modulation techniques is the fact that the nonlinear power amplifier tends to spread the spectrum and thus offset any spectrum efficiency advantage. Linearization techniques are presently being investigated, in the literature, in order to recover some of the lost spectrum, due to spreading. To this end, digital signal processing (DSP) techniques are thought to provide real time predistortion methods. Some of the complex modulation blocks, normally confined to analog circuitry, are being implemented using DSP circuitry. This paper will address the linearization techniques, for mobile satellite (MSAT) transceivers, that use an integrated DSP/radio frequency design.
A guide for DADiSP software, intended for use by the Lambda Point Experiment (LPE) Team during and after the United States Microgravity Payload (USMP)-1 mission, is presented. DADiSP is a Data Analysis and Display Software developed and marketed by DSP Development Corporation, Cambridge, Massachusetts. This guide is intended to be used in addition to the DADiSP Worksheet User Manual and Reference Manual which are supplied by the company with the software. Technical support for DADiSP is available from DSP at (617) 577-1133. Access to DADiSP on Acceleration Characterization and Analysis Project (ACAP) EGSE is being provided to the LPE team during USMP-1 for off-line processing of SAMS data.
The launch schedule for the Advanced Communication Technology Satellite (ACTS) spacecraft did not leave sufficient time for completion of the prototype ACTS Propagation Terminals (APT) prior to initiation of the APT production phase. In fact, the approach used was to construct and test all subassemblies of the terminal with special emphasis on the technically challenging portions. These include the RF front end that uses a state-of-the-art down converter which integrates a low noise amplifier, mixer, post amplifier, filter, and local oscillator port frequency doubler into a single small package. In addition, a new digital receiver that uses the latest DSP technology was developed. Both of these subassemblies were thoroughly tested. The highest risk technology in the APT program was the digital receiver. Several candidate algorithms and DSP chips were investigated early on, primarily under JPL sponsorship. A receiver was constructed based on Texas Instruments chip. The final prototype digital receiver was one based on an Analog Devices chip. The design and test results are documented in a report prepared for this grant. A Primary Design Review (PDR) was conducted 30 May 1991, and a Critical Design Review was held 7 Jul. 1992. Final complete documentation of the APT's will appear in the form of three reports: a hardware description report, a report on the data collection code (ACTS VIEW), and a report on the preprocessing code.
MODIS (Moderate Resolution Imaging Spectrometer), SeaWIFS (Sea-viewing Wide Field Sensor), Pathfinder, and DSP (Digital Signal Processor) objectives are summarized. An overview of current progress is given for the automatic processing database, client/server status, matchup database, and DSP support.