Engineering Commons^™

Noise Spectral Density As A Diagnostic Tool For Reliability Of P-N Junctions, Young Duck Kim

Dissertations

The feasibility of choosing noise-voltage spectral density as a prediction parameter for the degradation of p-n junctions has been examined both theoretically and through a series of life-tests.

Experimental facts show that the noise-voltage spectral density, S_v(w), observed in a p-n junction under the breakdown condition tends to be "white" (which contradicts the 1/f-noise theory), and S_v(w) is inversely proportional to the breakdown current (which contradicts the shot-noise theory). Furthermore, some p-n junctions display one or more multiple peaks of S_v(w) at different current levels which can not be explained by any of the …

A Study Of The Properties Of The Biconical Antenna, Kurt Frank Hafner Jr.

Theses

Expressions are found for the fields produced by TM and TEM modes along a finitely conducting biconical antenna. Expressions are also found for the TM and TEM fileds along a biconical antenna having a lossy dielectric coating. It is shown that the antenna losses produce an anntenuation of the the fields along the antenna. It is found that because there is a dispersion of the fields along the biconical antenna, the attenuation produced by the losses is, in genaral, not characterized by simple exponential.

A solution is obtained for the fields of the TEM wave along a biconical antenna coated …

Fault Protection With A Digital Computer, George D. Rockefeller

Theses

A fundamental basis has been developed for the use of a time-shared stored-program digital computer to perform many of the electrical power-system protective-relay functions in a substation. Logic operations are given to detect a fault, locate it and initiate the opening of the appropriate circuit breakers, whether the fault is in the station or on lines radiating from the station.

The instantaneous value of the station voltages and currents are sampled at a 0.5 ms rate, converted to digital form and stored for computer main-frame use. Operating times are compatible with the 25 ms breaker trip capability of modern two-cycle …

Linear And Adaptive Delta Modulation, John Edward Abate

Dissertations

New results are presented offering insight into the performance and optimization of linear and adaptive delta modulation, together with a comparison with pulse code modulation. The results are applied to three cases of practical importance: television, speech, and broadband signals.

The results presented can be grouped into the following three categories. First, a performance characterization of linear delta modulation (DM) is given. With the aid of certain empirical observations made from computer simulations, closed form expressions are found for granular noise, overload noise, and minimum quantization noise powers. These results permit the prediction of the optimum performance obtainable from DM …

Effects Of Partial Coherence On Holography, Michael Jay Lurie

Dissertations

The theory of two-beam holography is generalized to include quasi-monochromatic radiation of any degree of spatial coherence. It is shown that a clear, undistorted reconstruction can be obtained provided the reference beam is highly coherent. The effect of the partial coherence of the illumination is only to make the reconstructed image darker. Specifically, the amplitude of the radiation at any point of the image is proportional to the amplitude of the radiation leaving the corresponding point on the object during the exposure, times the magnitude of the coherence between the latter radiation and the reference beam. Holograms made using either …

Energy Transfer And Electron Conduction In The Fluid Transpiration Arc Column, Pin-Seng Tschang

Dissertations

The energy relaxation and electrical conductivity of an electron gas in one atmosphere argon arc discharge has been examined theoretically and observed quantitatively in an experimental arrangement. The plasma column utilized for study is the type generated in a fluid transpiration arc equipment in which the argon working fluid is injected through a porous graphite anode. The rate of forced convection is such as to insure significant electron-heavy particle nonequilibrium in the sample volume of interest. A simple model of a developing arc column with internal heat generation indicates that, with typical rates of argon injection realized in practice, the …

Improving The Reliability Of Electronic Systems By Minimization Of The Variances And Stabilization Of The Mean Values Of The System Performance Criteria, Emil Carl Neu

Dissertations

The parameters of an electronic system are not deterministic variables; but rather because of variations in manufacturing processes, they are randomly distributed variables. In addition, aging mechanisms will cause these parameters to drift with time. As a result of both of these factors, the system performance criteria deviate from their initial design center values. This research studied the effect of component parameter variations upon these electronic system performance criteria and then presented a thesis to minimize the effect of these variations.

The distributions of the performance criteria were obtained as functions of the parameter distributions, by first approximating the performance …

Design Of Feedback Control Systems With Transport Lag By Parameter Plane Techniques, Lawrence Eisenberg

Dissertations

A method is presented for the exact determination of absolute and relative stability of linear feedback control systems containing transport or distributed lag. All results are in terms of two variable system parameters. The method utilizes an extension of modern parameter plane techniques that allows for the inclusion of transcendental functions in the system characteristic equation. The design of controllers in linear systems containing transport lag is then considered. A design technique is proposed that allows for the systematic determination of two variable controller parameters in order to meet frequency or time domain design specifications.

The design technique is formulated …

Optimum Linear And Adaptive Polynomial Smoothers, Stanley Bruce Alterman

Dissertations

The design of optimum polynomial digital data smoothers (filters) is considered for linear and adaptive processing systems. It is shown that a significant improvement in performance can be obtained by using linear smoothers that take into account known a priori constraints or distributions of the input signal. The procedure for designing optimum (minimum mean square error) adaptive polynomial data smoothers is then discussed and analyzed. The optimum smoother makes use of a priori signal statistics combined with an adaptive Bayesian weighting of a bank of conditionally optimum smoothers. Use of this technique permits large improvements in performance with a minimum …

The Rimo Filter, Richard Thomas Modafferi

Theses

Up to the present time, there has existed no general method for obtaining the pole locations of minimum-phase constant time delay filters of desired selectivity. Since constant time delay filters are necessary for low distortion FM transmission, and minimum-phase filters are easy to construct and align, a general method for locating the poles of minimum-phase constant time delay filters would be of considerable importance. Presented in this paper is a procedure for locating the poles of minimum-phase constant time delay filters of desired selectivity, using a FORTRAN digital computer program. Two experimental FM receivers were built to test. the new …

The Effect Of Velocity On The Electrical Conductivity Of Blood, Judea Pearl

Theses

Although the change in the conductance of blood resulting from changes in its velocity has been noted by several investigators working with electrical impedance techniques, this parameter of measurement has heretofore not been investigated from the viewpoint of practical application to blood flow measurement.

In certain regions of the body such as the tooth pulp and the cranial cavity, the volume of the contained blood cannot fluctuate during a cardiac cycle because of the rigid wall of the chamber. Therefore, impedance pulses which have been obtained in studies on the tooth pulp, must be attributed to the rhythmical fluctuation of …

The Incandescent Lamp, E. F. Tenbroeke

Theses

A brief history of the development of the incandescent lamp.