Investigation into time and frequency domain of EMI induced noise in op amplifier and IC circuits

• Main Authors: Huang, Chien-Chang, 黃建璋
• Other Authors: 王納富
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/20209773881407663713

碩士 === 正修科技大學 === 電子工程研究所 === 99 === In this study is two parts：the first, the electromagnetic interference(EMI) in the In-tegrated Circuit(IC) and Operational Amplifier(OP) Circuit are studied theoretically and experimentally. This experiment produces the electromagnetic field (EMF) by the form of a coil wound on a ferromagnetic toroid containing an air gap. The electromagnetic field influenced the conducting wire(CW) in the circuit, the experiment used an oscilloscope and spectrum analyzer to measure the variation of circuit’s voltage and frequency of EMI. The experimental and numerical results reveal that the magnitude of the EMI-induced noise is related to the pulse amplitude, the output load, the parasitic capacitance, the interference frequency and the interference amplitude. It is shown that higher interference amplitude or frequency increase the harmonic noise. The second, the electromagnetic interference (EMI) in the light signal is studied the variation of the strength of light. This experiment produces the electromagnetic field in the tube by a coil on a solenoid, and influences the light signal of laser with a pulse wave. Using the PIN photodiode observed the variation of the pulse amplitude .The experimental and numerical result show that the magnitude of the EMF influence the strength of light signal is related to the number of the coil, the interference frequency and interference amplitude. It is shown that a higher interference amplitude or frequency decreases the strength of light.