Engineering Commons^™

An Experimental Investigation Of Receiver System Sensitivity, James Henry Johnson

Masters Theses

"A method of determining the minimum detectable power density incident at the receiving antenna of a UHF receiver is proposed. The minimum detectable power density is the power density required to produce a signal-to-noise ratio of unity in the output of the receiver. The proposed method includes the receiving antenna impedance, the necessary connecting transmission lines, and the receiver impedance.

It is shown that an error in the antenna directivity will produce a significant error in the overall sensitivity of a receiving system. Since the directivity is the most difficult system variable to determine experimentally, it is probably the limiting …

A Method For The Prediction Of Detection Ranges For Pulsed Doppler Radar, Phillip Orlan Brown

Masters Theses

"Modern radar systems must provide greater detection ranges both against high and low altitude targets because of the significant advances in weapon speed and range. Extended range indicates that the power transmitted by the radar must be increased. It follows, that ground return becomes a problem even at high altitudes.

There are at present three basic types of radars which are (1) pulsed, (2) continuous wave, and (3) pulsed doppler radar. The conventional pulsed radar now closely approaches the theoretical optimum performance; however, it does not have the inherent ability to distinguish between ground return and moving targets. The continuous …

An Experimental Investigation Of A Small Volume Sandwich Antenna In The 400 Megacycle Frequency Range, James Gilbert Smith

Masters Theses

"Scope of the Investigation: The small volume sandwich antenna was patterned after that of F. D. Clapp's which appears in an unpublished report written for the United States Navy. Clapp's antenna is shown in Figure 2. The antenna described in this report was investigated at approximately one-thousandth of the volume of the original Clapp antenna. Clapp's antenna was designed for the 225-400 megacycle range; while the author's model was designed for operation at 400 megacycles.

The objective of this investigation was to build a small volume sandwich antenna which could be adapted to satisfy the characteristics listed on page 1. …

Design And Construction Of An Automatic Antenna Pattern Plotter And Design Of A Microwave Absorbent Material, Norval D. Wallace

Masters Theses

"The following study consisted of two problems. One was the design and construction of an automatic antenna pattern plotter, and the other was the design of a microwave absorbing material for use in a darkroom"--Introduction, page 1.

Frequency Response Of Rotating Servo Components, Yehuda Rachovitsky

Masters Theses

"The frequency response approach to the design of automatic controls is the dominant one today. This approach in a strict sense may be said to have started with a paper in 1932 by Dr. H. Nyquist, a physicist at the Bell Telephone Laboratories. In this paper Dr. Nyquist was concerned with the stability of feedback amplifiers. This work can be said to have made possible the transcontinental telephone as well as modern radio and television. Dr. Hendrick Bode, mathematician at the Bell Laboratory, extended the results of Dr. Nyquist and obtained some simple design criteria that enabled even technicians without …

Mutual Coupling Between Loudspeakers, Robert Edward Bodenheimer

Masters Theses

Introduction: A complete system for reproduction of sound in the home consists of a chain whose first link is formed by a turntable pick-up and whose final link is made up of one or more loudspeakers. The loudspeaker is considered among the weaker links of this chain. In fact, the quality of sound from a reproducing system can be entirely dependent upon the performance of its loudspeaker system.

Only in the last few years have separate speakers been employed to reproduce a part of the frequency spectrum. In present day sound systems two or more identical speakers are often installed …

The Design And Analysis Of A Vacuum Tube D. C. Voltage Regulator Having Specified Characteristics, Charles Lamar Brantley

Masters Theses

Introduction: Advancing technology in the fields of Radar and Computers has placed increased emphasis on the performance of d. c. voltage regulators in the past few years, and there certainly is no reason to believe that this trend will subside in the future.

Vacuum tubes have been used for many years as a means of regulating output voltages of d. c. power supplies. The consequent development of a "cookbook" technique of design for such circuitry has led to many misconceptions and misunderstandings as to the characteristics available from the vacuum tube regulator and the methods of obtaining these characteristics. In …

Transients And Saturation In Synchronous Machines, Sabi J. Asseo

Masters Theses

"The synchronous machine can be regarded as the most important electrical device in today's industry and civilization. Although many improvements in the development of powerful electronic devices have been made, in recent years, the importance of the electrical power engineering field can never be overlooked in any way.

Most of electrical power engineering problems have been studied in the first quarter of the present century, and the results applied to industry for the betterment of electrical power production. As distribution and transmission systems used become extensively large, new problems such as the stability of interconnected power systems, have been introduced. …

Temperature Stabilized Transistor Direct Current Amplifier, William Lewis Metcalf Jr.

Masters Theses

"A stable direct current transistor amplifier is difficult to design for use at elevated temperatures. The above is true since transistor parameters and bias conditions are affected by temperature. When transistors are incorporated in direct coupled amplifier circuits, these variations in parameters and bias conditions usually result in unstable operation. It is the purpose of this thesis to investigate this problem and to design a stable direct current transistor amplifier which will operate satisfactorily at elevated temperatures.

This problem is of importance as such direct current amplifier circuits are found in airborne or missile servo systems. In such systems the …

Servomechanism Compensation With An Active Phase-Lead Network, Robert T. Dewoody

Masters Theses

"The problem is to develop a phase-lead compensation network for a servomechanism which will not reduce the low-frequency gain and thus decrease the velocity-lag error. The principal part of this thesis deals with the design of such an active phase-lead network. The active network does not have d-c coupling; this eliminates drift problems.

To illustrate an active phase-lead network a simple second order servomechanism is used as a basis for comparing three methods of compensation.

The first method is compensation with a conventional phase-lead network with a gain decrease. The second method is compensation with a conventional phase-lead network with …

Investigation Of The Current Distribution On An Antenna In A Waveguide, David J. Freeman

Masters Theses

"In a communication system composed of several networks and transmission systems, it is necessary for all parts of the system to be impedance matched so that medium energy transfer is possible.

One of the recent transmission systems which has been developed is the wave guide. With the advent of the wave guide the communication engineer is immediately faced with the problem of coupling existing systems and networks to his newly found mode of transmission.

Practically this coupling problem reduces to one of feeding radio frequency energy to the wave guide with some conventional transmission line such as a coaxial line. …

Mechanical Vibration Of Vacuum Tubes, Jerry Dale Swearingen

Masters Theses

"Since the beginning of the art of vacuum tube building, vacuum tube engineers have been faced with many mechanical problems as well as electrical problems.

Early mechanical problems were comparatively small because most of the tubes were used in stationary apparatus where little or no vibration was envolved.

As time went on, vacuum tubes were placed in portable equipment and this useage established the need for a tube that was mechanically strong enough to give reliable electrical behavior where the tube was subjected to considerable vibration….

Recently it has been shown that vacuum tubes operating in the instrument cabins of …

The Design And Construction Of An Electronic D-C Analog Computer, Frederick R. Wagner, William A. Paar

Masters Theses

"To make this project realizable with the funds available and in the time allowed, and to set forth some definite goals, the following objectives were adopted:

1. Design, construct, and place in working order a d-c electronic analog computer capable of solving 4th order linear differential equations with constant coefficients.
2. Include in the design provisions for real time computation, and also fast, repetitive operation.
3. Provide for later expansion of the computer installation.
4. Limit expenditures to $700"--Introduction, page 4.

A.C. Circuit Interruption, Palmer L. Anthony Jr.

Masters Theses

"In the last few years the transmission voltages have increased tremendously. Along with the voltage increase came increased load carrying ability for the circuits. The first few links of a new 330 KV transmission system are now under construction in this country. Sweden is already operating a 380 KV line. It is expected to carry a load as high as 850,000 KW on a single circuit.

Interconnection between systems in adjoining areas is a practice to get further operating benefits. The benefits are - reduction of necessary reserve capacity, increased load diversity, and decreasing losses.

Both of these developments bring …

The Design Of A Closed-Loop Voltage Regulator For A D-C Generator, Ernest P. Longerich

Masters Theses

"The methods of obtaining voltage regulation for a d-c generator are many, and they vary in complexity according to the requirements of the loads being supplied.

A need for zero voltage regulation is not uncommon in power supplies that are used in laboratory work. It is frequently not enough, however, to have a supply whose steady state regulation is zero; the need may also exist for fast transient response to changes in load.

In general, then, the criteria for excellent voltage-versus-load characteristics of a d-c power supply might be stated as follows:

1. It has zero steady state error.
2. It has …

Transfer Function Of The Modified Kramer System, David L. Hillhouse

Masters Theses

"The use of operational mathematics in the solution of engineering problems has grown tremendously in the last two decades, particularly during the last war. This has come about because of the facility with which problems which would be almost impossibly complicated or tedious to solve by classical methods can be solved using operational calculus.

The operational calculus, particularly the Laplace transform method, has become especially useful in the field of servomechanisms and controls. Here the constantly increasing complexity of systems used has resulted in very high order differential equations. The fact that the Laplace transform method makes it possible to …

Design Of A Galvanometer To Be Placed Within A Tubular Antenna For The Purpose Of Measuring Antenna Current Distribution, Ferdinand Henry Mullersman

Masters Theses

"The object of this paper is to design such a galvanometer for application to cylindrical UHF antennas and to discuss the procedure involving its use. The galvanometer will then be placed inside a completely isolated parasitic antenna and the distribution of current along the antenna will be measured"--Introduction, page 5.

An Experimental Study Of The Effect Upon The Current Distribution And Radiation Pattern Of Crossbars On Yagi Receiving Antennas, Gerald F. Sinnamon

Masters Theses

"The development and widespread use of radar systems in World War 11, and the post-war television boom, has brought about a large amount of investigation in antenna arrays. One of the types of antennas commonly used on radar systems during the early part of the war, and one which finds wide usage today as a television receiving antenna, is the well known Yagi antenna...

Since television antennas are usually mounted out of doors, the antenna must be made mechanically strong to prevent whipping or twisting due to wind, and to prevent sagging due to icing or to its own weight. …

Analysis Of Magnetic Amplifiers Based On Assumed Analytical Expressions Of B-H Characteristics, Wiley Talley Ruhl

Masters Theses

"In the past 10 years, magnetic amplifiers have received much attention in many different fields of engineering. Although the principles of this amplifier have been known since 1915, it has been forced into the background by the development of the vacuum tube amplifier, the need of better core material and better dry disk rectifiers.

The basic magnetic amplifier, or saturable reactor, is nothing more than an iron core reactance coil whose a-c impedance is controlled by a d-c premagnetization of the core. This d-c premagnetization may be obtained in a number of ways, the simplest of which is a separate …

Clipper Amplitude Modulator, Durmuş Öcal

Masters Theses

"An amplitude modulated wave is defined as a wave form in which the amplitude of a sinusoidal signal (carrier) is varied in accordance with a modulating signal whose frequency is much lower than the frequency of the carrier signal. Numerous devices have been found for generating an amplitude modulated wave. In some modulators the amplitude of the carrier is actually varied in accordance with the modulating signal. In other types of modulators the carrier and the modulating signal are simultaneously applied to a nonlinear element or circuit. The output of this non-linear element is a distorted wave containing many frequencies. …

Economic Analysis Of Secondary Distribution Networks, Charles F. Cromer

Masters Theses

"In the early history of commercial electricity in heavy load density areas, the d.c. Edison Network was developed extensively. As far as reliability is concerned it is exceeded by no system. At the present time it has been developed to the extent of automatic and non-automatic converters, motor-generator sets, booster sets and storage battery reserve capacity.

This type of network is fed from several substations in the area at utilization voltage.

As load densities have increased, the large amounts of copper required, the cost of substation sites and large rotating conversion equipment have made the expansion of the d.c. Network …

Investigation Of Vacuum Tubes As Four Terminal Networks, Vasil Uzunoglu

Masters Theses

"This thesis was undertaken with the aim of consolidating the most important work that has been done in the field of equivalent vacuum tube circuits which has been found to be highly disassociated.

The author of this thesis feels that this thesis is the most complete consolidation of information on equivalent vacuum tube circuits"--Introduction, page 3.

Problems In Theatre Lighting And Pre-Selective Elctronic Lighting Control, Hasan Orhan Aker

Masters Theses

"Until the recent years, because of the lack in technical know-how of play producers and on the other hand the limited knowledge of the engineers about stage technique, all the advantages provided by efficient stage lighting could not be exploited. Especially, the different problems encountered from the point of view of lighting control, could not be solved for a long time.

It has been proven from theatres built lately, that the stage lighting designs made without a thorough study of the various stage conditions and requirements lead to a tremendous increase in cost and also inefficient operation of the whole …

Design Of A Steam Power Plant To Be Erected In Mudanya, Turkey, Vahram Ogretmenoglu

Masters Theses

"The power plant, the design of which is submitted herewith, is to be erected in Turkey, at the center of the town of Kestik, in the district of Mudanya along the shores of the Marmora Sea. Mudanya is the harbor of the state of Brusa, and like most of the big cities, it is entirely electrified. However, electrification in Turkey has begun in the late twenty's; consequently, it has not yet been possible to bring electricity to the numerous small towns and villages. Several big projects have been undertaken for purposes of rural electrification, one of them being the erection …

A Study Of Radio Frequency Converters And Mixers, James J. Skiles

Masters Theses

"This thesis will present a detailed discussion of the principles of frequency conversion and the problems attendant to the design of converter stages. The topic of harmonic conversion has been singled out for a more extended treatment than is now available in the literature. This topic is the subject of the experimental investigation portion of this thesis. Harmonic conversion has applications in U-H-F receivers as well as in "Double Superheterodyne Receivers".

The discussion given to the frequency converter in the first section of this thesis will be without regard to any applications. General theory will be stressed, and most of …

Series Capacitors, Emcet Bilgeer

Masters Theses

"Static capacitors as an element of transmission and distribution circuits first appeared in the form of shunt capacitors. These shunt capacitors were primarily used in power factor correction. They can be regarded as a load in the circuit which draws a loading current. This loading current fleeing through the reactive line produces a voltage rise, thus reducing the voltage drop between sending and receiving ends. This phenomenon helps the voltage control of the feeder as well as power factor correction. The disadvantage of the shunt capacitor is its inflexibility. The shunt capacitor is connected across the line; hence the voltage …

Study Of Relay Behaviour Under System Oscillations And Out Of Step Conditions, Emil D. Grigoriadis

Masters Theses

"The recent developments in harnessing electrical power have opened a new field in the improvement and betterment of the existing types of relays and the development of new types. Thus about 1930 the manufacturers introduced the high speed circuit breaker with operating times of the order of 8 cycles and the engineers awoke to the possibilities of high speed or one-cycle relays.

Many developments took place since that time which gave us the improved forms of Instantaneous Overcurrent Protective schemes, the Distance Relay Protection, the Carrier Current Protection and many others. Later, because of the war time problems of increased …

A Survey Of Single Ended Tuned Grid Tuned Plate Class C Power Amplifiers, Chandrakant D. Gandhi

Masters Theses

"The analysis of tuned grid-tuned plate Class C power amplifiers has been treated by many authors in many ways. The methods differ in accuracy and in time required to obtain the end results. A survey of most important of these methods was taken up by the author of this thesis with an aim towards studying their accuracies, advantages and disadvantages. A general survey of this type of analysis has not been found in the literature. In this survey only the most important phases of the tuned grid-tuned plate single ended Class C power amplifiers are discussed.

This survey has been …

Electrical Analogue Computer For The Heat Pump, James Edward Goff

Masters Theses

(Taken from the Summary)

Because of the complex behavior of a cylindrical heat source-sink under intermittent operating conditions, analysis by analytical means is very difficult. Therefore an electrical analogy computer consisting of a distributed resistance capacitance model was designed and built. It was shown analytically that the behavior of this computer model was the same as that of the heat system. That the model was a true analogy is verified by the fact that data obtained from this model could be used to check certain heat flow problems previously solved by analytical means. Data were obtained for a …

Calculations Of Maximum Sag Of A Transmission Line With An Ice Load On One Span, Rodney A. Schaefer

Masters Theses

"An important problem concerning electric power lines is the calculation of the maximum sag occurring when there is an ice load on only one span. The object of this thesis is to determine a practical method for calculating the maximum sag of a transmission line, suspended on suspension insulators, with the aforementioned loading conditions. This paper is limited to the case where the supports of the transmission line are at equal elevations and all span lengths are equal"--Introduction, page 1.