| 摘要 |
<p>A status monitor for coaxial cable networks. The monitor is designed to be directly attached to an output port of an amplifier/repeater in the network and is used as an aid in trouble shooting faults in the network. The monitor comprises a detector (12 or 40) which generates a d.c. voltage indicative of the level of a pilot frequency signal on the network. This d.c. voltage is supplied to a plurality of voltage comparators (18, 20 and 22) which compare the d.c. voltage with different reference voltages in order to sense different fault conditions. If a fault condition is sensed, the outputs of the comparators are used by a tone selection logic (24) and an OR logic switch (26) to control a voltage controlled oscillator (30) to generate a modulating tone. A signal from a crystal controlled oscillator (32 or 48) or IF output of the detector (40) is modulated by the tone produced by the voltage controlled oscillator and radiated. This tone modulated radiated signal may then be used by a technician in field to detect both the location and the nature of the sensed fault in the network. </p> |
