| 摘要 |
A system for monitoring reverse paths of a bi-directional cable communicati on network such as a CATV network, to detect and analyze ingress signals enteri ng a reverse path and ending to a network sub-headend or headend through a corresponding one of communication lines, comprises a plurality of radio frequency signal detectors connected thereto. The radio frequency signal detectors are provided with bandpass filter for receiving any radio frequency signal within the frequency band used, to generate corresponding output signals indicative of the strength of the received radio frequency signal. Th output signal generated by the frequency signal detector which is coupled to the communication line corresponding to the ingress sign al carrying path is indicative of the strength of the received ingress signal with any received reverse signals. The system further comprises a signal processor for analyzing the detector output signals through comparison with one or more predetermined ingress thresholds to generate an alarm signal whenever the ingress signal is detected. The system further comprises a control computer receiving the alarm signal to generate monitori ng sequence control data indicative of the communication line corresponding to the ingress signal carrying path to be monitored. The system also comprises a selector switch having a plurality of inputs being connected to the communication lines and being responsive to the monitoring sequence control data to select the input connected to the communication line to be monitored, and signal monitoring instrumentation su ch as a spectrum analyzer and a broadband analyzer coupled to an output of the switching device and being responsive to the monitoring sequence control data for analyzing the ingress signal and generating alarm message data accordingly. The control computer receives the alarm message data to further generate diagnostic sequence control data for the monitoring instrumentation also used to determine source characteristics of the ingress signal.
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