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CRT显示终端由CRT显示器、主控板、电源和键盘组成。从电磁场理论来阐述:CRT显示终端中的每个元件和每根导线都会产生电磁干扰,表现最突出的是CRT显示器中视频放大、行输出电路的高频、高压、大电流及其电流传输线、行输出变压器、多种工作频率、系统晶振频率及它们的分频和高次谐波。通过电源线、电阻耦合、电容耦合、电感耦合及传输线等辐射传播干扰。并从电磁场辐射理论来进一步阐明CRT显示终端辐射量受到其内部的信号功率、频率和电流密度的影响,功率愈大,电流密度愈大。从理论上分析了在测试辐射干扰时,CRT显示终端的工作状态、颜色、亮度、字符及天线方位等的选择很关键。以试验来验证理论分析,并提出了CRT显示终端应做静电敏感度测试的见解。
CRT display terminal consists of CRT monitor, main control board, power supply and keyboard. From the electromagnetic field theory to explain: CRT display terminal in each element and each wire will have electromagnetic interference, the most prominent performance is the CRT display video amplification, line output circuit of high-frequency, high voltage, high current and its current transmission line, Line output transformer, a variety of operating frequency, the system crystal frequency and their frequency and higher harmonics. Through the power lines, resistance coupling, capacitive coupling, inductive coupling and transmission lines and other radiation transmission interference. And from the electromagnetic field radiation theory to further clarify the CRT display terminal radiation by its internal signal power, frequency and current density, the greater the power, the greater the current density. It is theoretically analyzed that the choice of operating status, color, brightness, character and antenna azimuth of CRT display terminal is crucial when testing radiated interference. To test to verify the theoretical analysis, and put forward the CRT display terminal should do electrostatic sensitivity test insights.