| 摘要 |
Method and apparatus for monitoring that a plurality of mutually subsequent signals are of substantially the same appearance and, thereby, are substantially alike, and for triggering an alarm and/or stop function in the event of signal loss and/or in the occurrence of one or more unknown and unacceptable deviations in the appearance of the monitored signal, and for preventing triggering of an alarm and/or stop function on the occurrence of one or more known and acceptable deviations in the appearance of the mutually subsequent signals, the monitored signal being digitalized and thereafter fed, on the one hand, to a blocking and comparator circuit for generation of a signal indicating unknown deviations, for triggering the alarm and/or stop function, and, on the other hand, to a registration circuit for registering the appearance of the signal and feeding of a signal to the blocking and comparator circuit of such type that known deviations in the digitalized signal are accepted so that the blocking and comparator circuit emits an output signal triggering an alarm and/or stop function only in response to unknown deviations in the monitored signal. |
