METHOD AND APPARATUS FOR DETECTING TROUBLE CONDITION

摘要

PURPOSE: To make it possible to discriminate between a false and a true RF signal by finding the level of a 1st sense RF signal and detecting the level of next one, and outputting a fault signal only when the former exceeds a specific level and the latter is generated within a specific time period. CONSTITUTION: An RF signal on a neutral lead wire 50 is inputted to the nondelay input 512 of a discriminating circuit 510 and a delay signal is inputted to the delay input 514 of the circuit 510. Then an electronic delay line 520 delays a radio frequency signal to the delay input 514 and this delay signal is sent to RFM 5 only when it is made evident by the analysis that the nondelay signal meets the standards. Consequently, an undesirable pulse signal is removed before the signal is inputted to the RFM 5 and the false and true RF signals can be discriminated.