在GTEM室中用射频连续波对某导弹装备上的数字控制电路进行电磁辐照.在一定的场强下,引入的电磁骚扰未导致被监测的与非门产生错误反转时,产生控制信号的自激多谐振荡器却受到了电磁干扰,主要表现为产生的方波控制信号的占空比增大.分别研究了谐波波源频率在80,100,300MHz和1GHz时电路受干扰的情况。发现:多谐振荡器对频率为100MHz的连续波干扰最敏感,对80,300MHz的干扰比较敏感,而对1GHz的连续波干扰不敏感,在每个频点,对方波控制信号的占空比随场强的变化进行了相关性拟合,并建立了数学模型.
A digital control circuit of a missile equipment is radiated by continuous RF(radio frequency)wave in a GTEM cell. Under a field intensity, although the electromagnetic disturbance produced hasn't made the NAND gate monitored produce wrong overturn, the free-running multivibrator which is used to produce control signal is seriously interfered. It is showed that the duty ratio of rectangular wave signal has changed. The interference is studied when the frequency of disturbance source is 80,100,300 MHz and 1 GHz. It is discovered that the multivibrator is more sensitive to 100 MHz than to 80 MHz and 300 MHz, and is insensitive to 1 GHz continuous wave. Correlation fitting is done to the change of duty ratio of the rectangular wave with the intensity of the field. A mathematical model is established.