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A study of the changes in electromagnetic radiation from a microprocessor due to changes in clock cycles and data programsSmith, Randall Wade 01 January 2001 (has links)
Electromagnetic compatibility (EMC) has become increasingly important in present electronic design. Modern high-speed circuitry has earned amplified attention from engineers due to its ability to interfere with neighboring circuitry through electromagnetic interference (EMI). As the operating speed and layout complexity of electronic circuit systems continues to increase, electromagnetic interference (EMI) becomes a serious issue facing circuit designers of the present and future. In this paper, the radiated emissions of a small PCB (including a microprocessor, SRAM, and flash memory) placed within a 1-GHz Crawford TEM (transverse electromagnetic) cell are analyzed. Various programs are executed while the microprocessor runs at different clock speeds. The dissimilarities in the radiated emission spectrums provided by the DUT (device under test) while running various programs at different clock speeds are compared and analyzed. All five programs run by the microprocessor show similar effects when the clock speed is varied. It is demonstrated that when the clock rate of the microprocessor increases, the overall radiation from the system increases. However, varying the software executed by the microprocessor is found to have effects on the emitted radiation pattern. The greatest noise within the radiated emission spectrum is found to come from programs in which the microprocessor communicates with the external SRAM chip. It is also found that the radiation levels for each program executed by the microprocessor change differently as the position of the microprocessor inside the TEM cell is varied. The fast paced lifestyle of modern society has undeniably led to an increase in desire for higher functionality of electronic devices. Whether it is a wireless device, a portable computer, or simply more electronic components inside an automobile, the need for electronics with more capabilities has become a standard in electronic design. However, to increase the function of a digital device, clock frequencies and software have to be altered. It is hoped that this paper will help engineers to take into consideration how changes in clock frequencies and software can affect the radiated EMI within their designs. An engineer's consideration of the effects of EMI within his/her design will help lead to safer, more reliable devices.
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An integral equation method for the evaluation of the frequency-dependent per unit length inductance and resistance matrices for a uniform multiconductor lossy transmission line systemVakanas, Loizos Petrou, 1964- January 1989 (has links)
The problem of electromagnetic field penetration in the finite-resistivity conductors of a uniform, multiple, coupled transmission line system (MTL) is considered. Under the assumption of quasi-transverse electric and magnetic (quasi-TEM) mode of propagation, the problem of determining the per-unit-length resistance and inductance matrices for such MTL systems reduces to solving a quasi-magnetostatic problem. An integral equation for the current density distribution inside the conductors is formulated and solved numerically using the method of moments. From straightforward energy considerations and the current density distribution, the per-unit-length resistance and inductance matrices are calculated. Several microstrip configurations are then analysed and the effects of the geometrical characteristics of the structures on the per-unit-length inductance and resistance matrices, as well as their frequency dependence are investigated.
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A system to measure the phase shift and attenuation of underground HF electromagnetic propagationSchulte, Joseph Thomas 1957- January 1989 (has links)
This thesis discusses the theory and limitations of a system that has been designed and constructed for the purpose of measuring the phase shift and attenuation of high-frequency (15 MHZ) electromagnetic waves propagating between two insulated antennas that have been lowered down air-filled boreholes (cased with PVC pipe) at San Xavier Mine, Pima County, Arizona. Both the transmitting and receiving antennas are center-fed, sleeve dipoles that have been tuned to approximately their resonant lengths. The insulated-sleeve dipole antenna is modelled as the inner conductor of a radiating, coaxial transmission-line, which allows simple transmission-line formulas to be used in approximating the antenna impedance and current distribution along the antenna. Experimental results at the San Xavier Mine indicate the analogy is valid. Consequently, the most easily interpreted and repeatable measurements have been made with the antennas centered in the borehole.
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Investigation of the wave impedance radiated by a loaded loopUpton, Miles Edwin Grimshaw January 1990 (has links)
No description available.
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Magnetohydrodynamics of swirling, recirculating flowDavidson, P. A. January 1986 (has links)
No description available.
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EMFs and gene activationLacy-Hulbert, Adam January 1995 (has links)
No description available.
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Scattered field decomposition for cylindrical scatterersBishop, P. K. January 1997 (has links)
No description available.
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An investigation of the EMC properties of modern microcontrollersSim, John Daniel January 1999 (has links)
No description available.
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IDENTIFICATION OF THE COMPLEX RESONANCES OF A DIELECTRIC SLAB AND A CIRCULAR CYLINDER.Simon, Jay Irwin. January 1984 (has links)
No description available.
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Near field effects of terahertz pulsesCarey, John Joseph January 2003 (has links)
No description available.
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