目前我们使用的地震仪DD—1、DK—1的警报器,容易到受外电干扰:一种是电源电压较大速率冲击干扰,一种是周围大电磁场的干扰。如电跳火,致使警报器工作不稳定,常常在打开仪器房电灯时警报就响,打雷时也会响,甚至附近有人打开一般的电灯开关时都可能响。在此情况下有的值班员为了避开干扰而把灵敏度调纸一点,这样一来,有地震时警报可能不响,即出现:有震不报,无震乱报的现象,影响测量速报工 At present, we use the seismometers DD-1, DK-1 sirens, easy to be subject to external interference: one is the impact of large power supply voltage surge and a large electromagnetic interference around the field. Such as electric flashover, resulting in unstable work of the alarm, often when opening the instrument room alarm lights, thunder will ring, or even when someone is turning on a general electric light switch may ring. In this case, some attendants in order to avoid interference and the sensitivity of the paper a little, so that there may be an earthquake alarm does not ring, that is: there is no earthquake, no shock and the phenomenon of newspaper reports, affecting the measurement report work