TEXAS UNIV AT AUSTIN DEFENSE RESEARCH LAB
Overview
Works:  51 works in 51 publications in 1 language and 51 library holdings 

Classifications:  TL501, 
Publication Timeline
.
Most widely held works by
TEXAS UNIV AT AUSTIN DEFENSE RESEARCH LAB
A Variable Bandwidth Constant K Filter(
Book
)
1 edition published in 1961 in English and held by 1 WorldCat member library worldwide
The problem consisted of designing a variable bandwidth constant gain filter for use with a superheterodyne pulse receiver capable of receiving ten microsecond and longer pulses. The desired results were achieved by electronically varying the shunt impedance of a three pole constant K filter 'T' section. This solution introduced the additional problem of designing a very low output impedance amplifier. A high gain feedback cathode follower is analyzed and designed to meet this problem. The operational characteristics of the variable bandwidth filter and the transient analysis of a constant K filter are included. (Author)
1 edition published in 1961 in English and held by 1 WorldCat member library worldwide
The problem consisted of designing a variable bandwidth constant gain filter for use with a superheterodyne pulse receiver capable of receiving ten microsecond and longer pulses. The desired results were achieved by electronically varying the shunt impedance of a three pole constant K filter 'T' section. This solution introduced the additional problem of designing a very low output impedance amplifier. A high gain feedback cathode follower is analyzed and designed to meet this problem. The operational characteristics of the variable bandwidth filter and the transient analysis of a constant K filter are included. (Author)
Ionospheric refraction errors measured in the doppler shift of radio transmissions from arti ficial earth satellites(
Book
)
1 edition published in 1963 in English and held by 1 WorldCat member library worldwide
Data from eightyfive passes of Satellite 61151 occurring from September, 1961, to June, 1962, are chosen to illustrate variations of electron density resulting from time of day, direction of the pass, and seasonal changes. Investigation of the plotted data indicate the variations in magnitude of the higher order refraction error terms. The data also show evidence of horizontal and vertical gradients i: electron density. The Appendix presents an error analysis of the refraction error digital computation program from which the plotted data are obtained. Synthesized Doppler data with varying amounts of error are processed by the IBM 1620 and the results are shown. (Author)
1 edition published in 1963 in English and held by 1 WorldCat member library worldwide
Data from eightyfive passes of Satellite 61151 occurring from September, 1961, to June, 1962, are chosen to illustrate variations of electron density resulting from time of day, direction of the pass, and seasonal changes. Investigation of the plotted data indicate the variations in magnitude of the higher order refraction error terms. The data also show evidence of horizontal and vertical gradients i: electron density. The Appendix presents an error analysis of the refraction error digital computation program from which the plotted data are obtained. Synthesized Doppler data with varying amounts of error are processed by the IBM 1620 and the results are shown. (Author)
Shannon's Theorem(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This report is concerned with some of the practical aspects of Shannon's Theorem, i.e., that a bandlimited time series is completely determined by its value at equally spaced time intervals, delta t, if 1/2 delta t is greater than the bandwidth. Thus, f(t) = sum over n of f(n delta t) h(t  n delta t), where 1/2 delta t is greater than the bandwidth of f. In practice, f is only approximately band limited and the series contains only a finite number of terms. In this report, the effects of bandwidth and truncation of the series are studied. (Author)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This report is concerned with some of the practical aspects of Shannon's Theorem, i.e., that a bandlimited time series is completely determined by its value at equally spaced time intervals, delta t, if 1/2 delta t is greater than the bandwidth. Thus, f(t) = sum over n of f(n delta t) h(t  n delta t), where 1/2 delta t is greater than the bandwidth of f. In practice, f is only approximately band limited and the series contains only a finite number of terms. In this report, the effects of bandwidth and truncation of the series are studied. (Author)
Quarterly Progress Report Number 4, 1 May  31 July 1967(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
It was pointed out in the previous progress report that the techniques for computing a Cepstrum have certain shortcomings in a mathematical sense. These restrictions were placed on the technique by certain approximations and assumptions that were made concerning the relative amplitudes of the original signal and echoes. This past quarter, effort was made to derive alternate techniques for computing Cepstrum, using as few mathematical assumptions as possible. (Author)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
It was pointed out in the previous progress report that the techniques for computing a Cepstrum have certain shortcomings in a mathematical sense. These restrictions were placed on the technique by certain approximations and assumptions that were made concerning the relative amplitudes of the original signal and echoes. This past quarter, effort was made to derive alternate techniques for computing Cepstrum, using as few mathematical assumptions as possible. (Author)
The effect of large interaural time differences upon the judgement of sidedness by
Hugh Carlton Blodgett(
Book
)
1 edition published in 1954 in English and held by 1 WorldCat member library worldwide
1 edition published in 1954 in English and held by 1 WorldCat member library worldwide
Numerical Simulation of a Linear Filter by Elgin Maurice Davis(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This paper investigates certain properties of a method which calculates a sample of a stationary Gaussian random process with a specified power spectral density function. The study determines to what degree this method simulates a linear filter. Also included are correlation analyses of equidistributed sequences which are used in the method. (Author)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This paper investigates certain properties of a method which calculates a sample of a stationary Gaussian random process with a specified power spectral density function. The study determines to what degree this method simulates a linear filter. Also included are correlation analyses of equidistributed sequences which are used in the method. (Author)
A Summary on Reflection and Scattering of Acoustic Waves from Model Surfaces(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
These studies have included both analytical and experimental investigations, with the experimental work being done in a laboratory tank which has provisions for precise control of the parameters of the experiment. Fullscale experiments at sea are expensive and time consuming, and particular aspects of reflection theory are often obscurred by sea or bottom conditions that cannot be controlled. The smallscale experiments in the acoustic tank with model surfaces provide information rapidly and accurately to compare with mathematical models. These mathematical models can then be used to predict the reflection and scattering of sound by the ocean boundaries for fullscale conditions
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
These studies have included both analytical and experimental investigations, with the experimental work being done in a laboratory tank which has provisions for precise control of the parameters of the experiment. Fullscale experiments at sea are expensive and time consuming, and particular aspects of reflection theory are often obscurred by sea or bottom conditions that cannot be controlled. The smallscale experiments in the acoustic tank with model surfaces provide information rapidly and accurately to compare with mathematical models. These mathematical models can then be used to predict the reflection and scattering of sound by the ocean boundaries for fullscale conditions
Quarterly Progress Report Number 1, 1 August  31 October 1966(
Book
)
1 edition published in 1966 in English and held by 1 WorldCat member library worldwide
Contract NObsr95181 has two basic partsone to investigate the utility of cepstrum analysis as an aid to active sonar classification, and the other to develop computer techniques to help with the problem of choosing sonar systems and specific relevant proposals on the basis of optimum (costeffectiveness) return
1 edition published in 1966 in English and held by 1 WorldCat member library worldwide
Contract NObsr95181 has two basic partsone to investigate the utility of cepstrum analysis as an aid to active sonar classification, and the other to develop computer techniques to help with the problem of choosing sonar systems and specific relevant proposals on the basis of optimum (costeffectiveness) return
Design of a SixChannel Electronic Gate by Jerry G Cole(
Book
)
1 edition published in 1961 in English and held by 1 WorldCat member library worldwide
This thesis presents the development and design of a sixchannel electronic gate for sampling dc signals. Sixdiode gates and transistor switching circuits are the basic elements of te sixchannel gate. The primary design criteria are wide dynamic range, good linearity, and gain of approximately unity. Analysis of the switching times of the transistor switch is developed. The design values for the switch are also calculated. The other components of the sixchannel gate have been adequately presented in literature; therefore, only the design values for these components are given. Measurements of the completed gate are presented. A dynamic range of 50 db and a gain of 0.965 is achieved. (Author)
1 edition published in 1961 in English and held by 1 WorldCat member library worldwide
This thesis presents the development and design of a sixchannel electronic gate for sampling dc signals. Sixdiode gates and transistor switching circuits are the basic elements of te sixchannel gate. The primary design criteria are wide dynamic range, good linearity, and gain of approximately unity. Analysis of the switching times of the transistor switch is developed. The design values for the switch are also calculated. The other components of the sixchannel gate have been adequately presented in literature; therefore, only the design values for these components are given. Measurements of the completed gate are presented. A dynamic range of 50 db and a gain of 0.965 is achieved. (Author)
An Underwater Sound Level Meter by James Joseph Truchard(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This thesis describes the design and operation of an underwater sound pressure level meter. The instrument measures ambient noise levels in water
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
This thesis describes the design and operation of an underwater sound pressure level meter. The instrument measures ambient noise levels in water
Summary of studies on the measurement of local skin friction by means of the surface impact or Preston tube by J. C Westkaemper(
Book
)
1 edition published in 1964 in English and held by 1 WorldCat member library worldwide
This report summarizes work done on the use of the surface impact probe, or Preston tube, method of measuring skin friction in turbulent, compressible boundary layers. The theory for incompressible flow was extended to the case of adiabatic, compressible flow, and the extended theory was experimentally shown to be valid. It has also been demonstrated that the extension is applicable to adiabatic flow with moderate adverse pressure gradients. Experimental and theoretical efforts to apply the impact probe method to compressible flows with moderate, aerodynamic heating were only partially successful. (Author)
1 edition published in 1964 in English and held by 1 WorldCat member library worldwide
This report summarizes work done on the use of the surface impact probe, or Preston tube, method of measuring skin friction in turbulent, compressible boundary layers. The theory for incompressible flow was extended to the case of adiabatic, compressible flow, and the extended theory was experimentally shown to be valid. It has also been demonstrated that the extension is applicable to adiabatic flow with moderate adverse pressure gradients. Experimental and theoretical efforts to apply the impact probe method to compressible flows with moderate, aerodynamic heating were only partially successful. (Author)
Sea, Land, and Rain Clutter Measurement II(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
A phasestable pulse radar system with dual frequency and dual range modes of operation was built to study radar clutter. Tests using the radar have resulted in sea and rain clutter data which are being studied by APL/JHU. Instrumentation of the radar was covered in DRL537 'Sea, Land, and Rain Clutter Measurement' (U) dated 3 May 1966. The present report covers modifications made to the system in 1966. It described rain clutter measurements made in Austin and sea clutter measurements made in Galveston, Texas and Cape Cod, Massachusetts. (Author)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
A phasestable pulse radar system with dual frequency and dual range modes of operation was built to study radar clutter. Tests using the radar have resulted in sea and rain clutter data which are being studied by APL/JHU. Instrumentation of the radar was covered in DRL537 'Sea, Land, and Rain Clutter Measurement' (U) dated 3 May 1966. The present report covers modifications made to the system in 1966. It described rain clutter measurements made in Austin and sea clutter measurements made in Galveston, Texas and Cape Cod, Massachusetts. (Author)
Effects of Several Types of Damping on the Dynamical Behavior of Harmonically Forced SingleDegreeofFreedom Systems by Jimmy Frank Byers(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
In general, the investigation of practical dynamical systems is more heuristic than rigorous; consequently, most literature attempts to provide a conceptual key to the general treatment of the response by correlation with linear theory. Practically none of this literature sets forth any new ideas of basic methods of attack. The usual attack is by extending present classical methods rather than by inventing new basic approaches. The major limitation found in the existing work is the lack of comprehensive understanding of the basic parameters of simple nonlinear oscillators. This thesis presents an accurate solution of several types of damping on the dynamical behavior of harmonically forced singledegreeoffreedom systems. The study is based on the fundamental parameters of the system. The fundamental response is described with reference to the equivalent damping energy, the Ritz method, and dimensional analysis. Dimensional analysis is used to develop a method for predicting the general response diagram characteristics. The high accuracy of the solutions permitted the collection of some very important design data. The results are presented in both graphical and tabular from and may be useful to those engaged in calibration, design, and data analysis of work requiring an accurate solution. Also, the linearized methods give results sufficiently accurate for many engineering applications. The prediction of response characteristics by dimensional analysis should be of interest. The timehistories of displacement, velocity, and acceleration are presented along with the response diagrams of displacement, velocity, acceleration, phase angle, and energy curves by both the linear and accurate solutions. (Author)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
In general, the investigation of practical dynamical systems is more heuristic than rigorous; consequently, most literature attempts to provide a conceptual key to the general treatment of the response by correlation with linear theory. Practically none of this literature sets forth any new ideas of basic methods of attack. The usual attack is by extending present classical methods rather than by inventing new basic approaches. The major limitation found in the existing work is the lack of comprehensive understanding of the basic parameters of simple nonlinear oscillators. This thesis presents an accurate solution of several types of damping on the dynamical behavior of harmonically forced singledegreeoffreedom systems. The study is based on the fundamental parameters of the system. The fundamental response is described with reference to the equivalent damping energy, the Ritz method, and dimensional analysis. Dimensional analysis is used to develop a method for predicting the general response diagram characteristics. The high accuracy of the solutions permitted the collection of some very important design data. The results are presented in both graphical and tabular from and may be useful to those engaged in calibration, design, and data analysis of work requiring an accurate solution. Also, the linearized methods give results sufficiently accurate for many engineering applications. The prediction of response characteristics by dimensional analysis should be of interest. The timehistories of displacement, velocity, and acceleration are presented along with the response diagrams of displacement, velocity, acceleration, phase angle, and energy curves by both the linear and accurate solutions. (Author)
Generalized figures of merit for infrared imaging systems(
Book
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Generalized equations for spectral noiseequivalent power (NEP sub lambda), signaltonoise ratio, and noiseequivalent temperature difference (NETD) are derived in this report; and a new figure of merit called noiseequivalent fractional emissivity (NEFE) is obtained. These formulas were developed for use in evaluation and comparison of passiveinfrared terrainimaging systems and are proposed as generalized figures of merit for such systems. Approximations are kept to a minimum, and corrections are included for spatial and temporal frequency responses which have hitherto been neglected. The new equations are derived, their use and the data requirements are discussed, a sample calculation is given, and a technique for system comparison in terms of subsidiary figures of merit called performance factors is proposed. Values for the two definite integrals required for computing the figures of merit are given in the Appendix together with the data used and the method of computation. (Author)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Generalized equations for spectral noiseequivalent power (NEP sub lambda), signaltonoise ratio, and noiseequivalent temperature difference (NETD) are derived in this report; and a new figure of merit called noiseequivalent fractional emissivity (NEFE) is obtained. These formulas were developed for use in evaluation and comparison of passiveinfrared terrainimaging systems and are proposed as generalized figures of merit for such systems. Approximations are kept to a minimum, and corrections are included for spatial and temporal frequency responses which have hitherto been neglected. The new equations are derived, their use and the data requirements are discussed, a sample calculation is given, and a technique for system comparison in terms of subsidiary figures of merit called performance factors is proposed. Values for the two definite integrals required for computing the figures of merit are given in the Appendix together with the data used and the method of computation. (Author)
Quarterly Progress Report Number 3, 1 July30 September 1968(
Book
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Defense Research Laboratory (DRL) personnel assisted in calibrating the receiving portion of the sonar system. Repeating the installation checkout required many calibration adjustments, the most troublesome of which was the correction of tape path alignment errors on the PME. Standard acoustic measurements were made on the system transmitter and receiver. Audio scanner receive sensitivity of 17 dB re 1 microbar was measured, with side lobe suppression a relatively poor 13 dB. The receive bandwidth was modified for the testing project; the measured response is shown on Fig. 1. A few individual stave measurements were performed with the results shown on Figs. 2 and 3. Figure 2 shows the receiving response of stave 1, and Fig. 3 shows a comparison of the acoustic signal response of several transducers staves. The staves were connected to the preamplifiers during these measurements
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Defense Research Laboratory (DRL) personnel assisted in calibrating the receiving portion of the sonar system. Repeating the installation checkout required many calibration adjustments, the most troublesome of which was the correction of tape path alignment errors on the PME. Standard acoustic measurements were made on the system transmitter and receiver. Audio scanner receive sensitivity of 17 dB re 1 microbar was measured, with side lobe suppression a relatively poor 13 dB. The receive bandwidth was modified for the testing project; the measured response is shown on Fig. 1. A few individual stave measurements were performed with the results shown on Figs. 2 and 3. Figure 2 shows the receiving response of stave 1, and Fig. 3 shows a comparison of the acoustic signal response of several transducers staves. The staves were connected to the preamplifiers during these measurements
Biannual Status Report Number 5 For Contract NObsr93175, 1 January through 30 June 1967(
Book
)
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
Report on the AN/SQS23 Digital FM Classifier
1 edition published in 1967 in English and held by 1 WorldCat member library worldwide
Report on the AN/SQS23 Digital FM Classifier
Generation of a Stationary Gaussian Random Process with a Specified Power Spectral Density Function by Walter Matuska(
Book
)
1 edition published in 1966 in English and held by 1 WorldCat member library worldwide
This paper gives a method for generating digitally a time series with a given power spectral density function. A computer program to carry out this method was written for the Control Data Corporation 3200 computer, and the program was tried on some specific example problems. Then for each of these examples, the power spectral density function of the generated time series was compared with the specified, theoretical power spectral density function
1 edition published in 1966 in English and held by 1 WorldCat member library worldwide
This paper gives a method for generating digitally a time series with a given power spectral density function. A computer program to carry out this method was written for the Control Data Corporation 3200 computer, and the program was tried on some specific example problems. Then for each of these examples, the power spectral density function of the generated time series was compared with the specified, theoretical power spectral density function
Experimental investigation of the effects of surface roughness on compressible turbulent boundary layer skin friction and
heat transfer by Frank Levi Young(
)
1 edition published in 1965 in English and held by 0 WorldCat member libraries worldwide
An experimental investigation was carried out to determine the effects of surface roughness on the turbulent boundary layer skin friction and heat transfer rates in air at a Mach number of 4.93. Four flat plate model configurations were tested. Simultaneous measurements of the local skin friction and heat transfer were made. The results of these measurements and of boundary layer pressure surveys are presented. Agreement of the smooth plate results with accepted theories acts to substantiate the results of measurements using the roughsurfaced models. A method is given to determine the equivalent incompressible sandgrain roughness of a surface based on experimental knowledge of the skin friction in compressible flow. In addition, a method to account for heat transfer effects in the calculation of skin friction coefficients for rough plates is suggested. Using the experimental results, the validity of the Reynolds analogy between heat transfer and skin friction is examined. A method to determine the Reynolds number based on the length of the turbulent boundary layer from measurements of the skin friction and momentum thickness for smooth or rough flat plates is also given
1 edition published in 1965 in English and held by 0 WorldCat member libraries worldwide
An experimental investigation was carried out to determine the effects of surface roughness on the turbulent boundary layer skin friction and heat transfer rates in air at a Mach number of 4.93. Four flat plate model configurations were tested. Simultaneous measurements of the local skin friction and heat transfer were made. The results of these measurements and of boundary layer pressure surveys are presented. Agreement of the smooth plate results with accepted theories acts to substantiate the results of measurements using the roughsurfaced models. A method is given to determine the equivalent incompressible sandgrain roughness of a surface based on experimental knowledge of the skin friction in compressible flow. In addition, a method to account for heat transfer effects in the calculation of skin friction coefficients for rough plates is suggested. Using the experimental results, the validity of the Reynolds analogy between heat transfer and skin friction is examined. A method to determine the Reynolds number based on the length of the turbulent boundary layer from measurements of the skin friction and momentum thickness for smooth or rough flat plates is also given
Acoustic Reflection and Transmission Properties of Several Transducer Window Materials(
)
1 edition published in 1978 in English and held by 0 WorldCat member libraries worldwide
The transmission, reflection, and absorption characteristics of a material largely determine its usefulness in underwater sound applications. Uses may include transducer windows, sonar domes, sound reflectors, and linings for test tanks. Most of the experimental data available in the literature are for normal incidence of a plane wave on the material. However, in some applications it is desirable to know the acoustic properties of a material for angles of incidence other than normal. For these reasons a test system was devised to experimentally determine the acoustic properties of materials over a wide range of incident angles. Theoretically, the most straightforward approach to the case of arbitrary incidence is found in Brekhovskikh. The expressions for transmission and reflection coefficients will be used to compare theory and experiment. Hence it is the purpose of this paper to experimentally determine these coefficients for AbsonicA, Plexiglas, Soab, Polyethylene, and Fiberglass for frequencies ranging from 100500 kc, compare the results with theory, and then examine their usefulness in underwater sound applications based upon these results
1 edition published in 1978 in English and held by 0 WorldCat member libraries worldwide
The transmission, reflection, and absorption characteristics of a material largely determine its usefulness in underwater sound applications. Uses may include transducer windows, sonar domes, sound reflectors, and linings for test tanks. Most of the experimental data available in the literature are for normal incidence of a plane wave on the material. However, in some applications it is desirable to know the acoustic properties of a material for angles of incidence other than normal. For these reasons a test system was devised to experimentally determine the acoustic properties of materials over a wide range of incident angles. Theoretically, the most straightforward approach to the case of arbitrary incidence is found in Brekhovskikh. The expressions for transmission and reflection coefficients will be used to compare theory and experiment. Hence it is the purpose of this paper to experimentally determine these coefficients for AbsonicA, Plexiglas, Soab, Polyethylene, and Fiberglass for frequencies ranging from 100500 kc, compare the results with theory, and then examine their usefulness in underwater sound applications based upon these results
Guide to the selection of acoustic filters for liquidfill systems by E. L Hixson(
)
1 edition published in 1962 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1962 in English and held by 0 WorldCat member libraries worldwide
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