Millimeter wave (mmWave) radar systems are a leading technology in autonomous vehicle object sensing. The radar’s ability to detect surrounding objects is critical to its performance. One method of increasing object detection performance is to enhance object visibility. Frequency selective reflectors can increase object visibility. This work examines the performance of a mmWave 77 GHz radar system developed by Texas Instruments in conjunction with frequency selective surfaces. Two bandpass frequency selective surfaces are designed and fabricated using a loaded cross aperture configuration to analyze their application to object detection. The chosen design frequencies are 8 GHz and 79 GHz. The frequency selective surfaces are designed and simulated in 3-D electromagnetic simulation software, High Frequency Structure Simulator (HFSS). The frequency selective surfaces are fabricated on 127μm thick FR4 dielectric. The 8 GHz frequency selective surface demonstrates bandpass center frequency at 8.12 GHz. The 8 GHz and 79 GHz frequency selective surface reflection characteristics are compared to a copper sheets with the same physical cross section as each respective design. Although different testing methodology is used for each design, both frequency selective surfaces demonstrate bandpass characteristics at their respective design frequencies.

The problem of measuring low values of slip of induction machines is present in most Electrical Engineering laboratories. A rather high accuracy of the determination is necessary for theoretical calculations of motor loading, using equivalent circuit techniques. Conventional methods of determining slip fail to give high accuracy at low values of slip. This thesis presents a solution to this problem by describing the design and construction of a precision slip frequency detector of nominal cost. The principle employed is that of beat frequency comparison of the rotor shaft speed against line frequency. The output of the beat frequency detector actuates a multivibrator-differentiating circuit, the output of which triggers an electro-mechanical counter. A photoelectric pickup device for determining shaft speed is also discussed.

"When the subject of the use of FM radio in the public schools was suggested by the writer as a subject for a research paper one of the first comments made by a fellow student was, 'Radio is a dead issue. Television has already made it out of date.' This comment immediately made the subject a challenge. Had we in America, in less than a generation, advanced to rapidly that one of the world's greatest media of communication was already out of date? The writing of this paper is an effort to answer that question, and in answering it to present a picture of the status of frequency modulation broadcasting in the public schools throughout the nation today"--Introduction. / Typescript. / "August, 1953." / "Submitted to the Graduate Council of Florida State University in partial fulfillment of the requirements for the degree of Master of Arts." / Advisor: John W. Mitchell, Professor Directing Paper. / Includes bibliographical references (leaves 67-68).

The Interactive Video Data Service (IVDS) system allows consumers to browse the Internet, request information on products or services, make purchases, indicate preferences, and perform other interactive applications. To provide this service, the IVDS system has three subsystems: Consumer Control (CC), Cell Repeater (CR), and Host subsystem. In the CC subsystem, an IVDS transceiver box is placed near a television set. Once the consumer sends a command to the transceiver box using a standard television/VCR/Cable remote control, the transceiver box receives information embedded in the television audio, and then transmits the information to the CR subsystem as a radio frequency (RF) spread spectrum message. The CR subsystem decodes the spread spectrum message and forwards it to the Host subsystem for processing. Located in the CR subsystem, a custom designed circuit board, called the decoder board, uses surface mounted components to decode and packetize the spread spectrum message for transfer to the CR main processor. This paper provides a functional description of the hardware components on the decoder board, and describes the hardware/software developed for interfacing the decoder board to the radio receiver and to the CR main processor. Hardware modifications were needed to correct timing problems between components. Software was developed to initialize the components for downconverting, despreading, and demodulating spread spectrum messages, and to packetize them for transfer to the CR main processor. This paper also discusses the tests used to verify both the performance of the decoder board software and the operation of the hardware components. / Master of Science

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The purpose of the study was to cover the impact of variable frequency drives in to-day's industry. A partial aim was also to study perspectives regarding the advantages and disadvantages of the variable frequency drive, its function based on sustainability, production efficiency and demand. The study was based on a qualitative research method, and the empirical material has been based on six semi-structured interviews from industries that currently use variable frequency drives. The results and parts of the study’s purpose were analysed based on previous research and theoretical perspectives. The results mainly show that variable frequency drives contribute to energy savings in our industries. Energy saving was also seen as one of the component's main ad-vantages, followed by the fact that it was considered cost effective in relation to its long lifetime. The cost and complexity of the product were identified as the compo-nent's disadvantages. In relation to sustainability, variable frequency drives mainly match with two of the goals in Agenda 2030, sustainability goals 9 and 12. In this regard, the variable fre-quency drives energy saving is central to the product from a sustainability point of view. In relation to production efficiency, variable frequency drives were found to be more energy efficient, and for that reason affect the process flow for the better, which indicates increased production efficiency. The component was considered as a flexible production solution that enables flow control, as well as maintaining a con-sistent quality of the production flow. Based on the results of the study, the demand that exist today for variable frequency drives only seems to increase. It is stated that there is a great demand today, while depending on the nation, it only seems to be expanding.

Under weak turbulence theory, we will use the random thin phase screen model and the Kolmogorov power-law spectrum to derive approximate models for the scintillation index, covariance function of irradiance fluctuations, and temporal spectrum of irradiance fluctuations for collimated beams. In addition, we will provide an expression for the quasi-frequency of a collimated beam and investigate the relationship between the quasi-frequency and the maximum width of the normalized temporal spectrum of irradiance for a collimated beam.

<p> Using a Q-spoiled Nd-glass laser, an experimental investigation of frequency doubling in NiSO4•6 H2O was carried out. The frequency doubling was observed to occur at a phase matching angle of 56° ± 1°. Experimentally, it is shown that the fundamental frequency at λ = 1.06 μm is an O-ray while the doubled frequency at λ = .53μm is an E-ray. Since the amplitude for electric dipole frequency doubling in NiSO4•6 H2O is zero, these observations are unusual. The observations are attributed to magnetic dipole and/or electric quadrupole frequency doubling. Evidence to support this view comes from the magnitude of the effect and from its azimuthal dependence. The electric quadrupole type frequency doubling is consistent with the data only if the susceptibility coefficients satisfy the relation QאEE =1/2 (QאEE - QאEE ) 1212 1111 1122 </p> / Thesis / Doctor of Philosophy (PhD)

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